Initial checkin.

.gitignore

@@ -0,0 +1,14 @@
+_ReSharper.*
+MeasureIt
+*.vsp
+TestResults
+obj
+bin
+*.suo
+*.user
+*.trx
+StyleCop.Cache
+*.vs10x
+*.tmp
+UpgradeLog.*
+_UpgradeReport_Files

Microsoft.Validation.sln

@@ -0,0 +1,20 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 11
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.Validation", "Microsoft.Validation\Microsoft.Validation.csproj", "{E016A630-A79B-4B5D-8997-E66581D62B81}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{E016A630-A79B-4B5D-8997-E66581D62B81}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E016A630-A79B-4B5D-8997-E66581D62B81}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E016A630-A79B-4B5D-8997-E66581D62B81}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E016A630-A79B-4B5D-8997-E66581D62B81}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal

Microsoft.Validation/Assumes.InternalErrorException.cs

@@ -0,0 +1,79 @@
+//-----------------------------------------------------------------------
+// <copyright file="Assumes.InternalErrorException.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+    using System.Diagnostics;
+    using System.Diagnostics.CodeAnalysis;
+    using System.Globalization;
+    using System.Runtime.Serialization;
+
+    /// <content>
+    /// Contains the inner exception thrown by Assumes.
+    /// </content>
+    internal partial class Assumes
+    {
+        /// <summary>
+        /// The exception that is thrown when an internal assumption failed.
+        /// </summary>
+        [Serializable]
+        [SuppressMessage("Microsoft.Design", "CA1064:ExceptionsShouldBePublic", Justification = "Internal exceptions should not be caught.")]
+        private class InternalErrorException : Exception
+        {
+            /// <summary>
+            /// Initializes a new instance of the <see cref="InternalErrorException"/> class.
+            /// </summary>
+            public InternalErrorException(string message = null, bool showAssert = true)
+                : base(message ?? Strings.InternalExceptionMessage)
+            {
+                ShowAssertDialog(showAssert);
+            }
+
+            /// <summary>
+            /// Initializes a new instance of the <see cref="InternalErrorException"/> class.
+            /// </summary>
+            public InternalErrorException(string message, Exception innerException, bool showAssert = true)
+                : base(message ?? Strings.InternalExceptionMessage, innerException)
+            {
+                ShowAssertDialog(showAssert);
+            }
+
+            /// <summary>
+            /// Initializes a new instance of the <see cref="InternalErrorException"/> class.
+            /// </summary>
+            protected InternalErrorException(SerializationInfo info, StreamingContext context)
+                : base(info, context)
+            {
+            }
+
+            /// <summary>
+            /// Show the assert if showAssert==true.
+            /// </summary>
+            /// <param name="showAssert">Whether to show the assert.</param>
+            /// <remarks>
+            /// The assertion dialog may yet be suppressed if 
+            /// ((DefaultTraceListener)System.Diagnostics.Trace.Listeners["Default"]).AssertUiEnabled == false
+            /// </remarks>
+            private void ShowAssertDialog(bool showAssert)
+            {
+                if (showAssert)
+                {
+                    // In debug builds, throw up a dialog.  This allows a dev to 
+                    // attach a debugger right at the point where the exception is
+                    // thrown rather than at the point where the exception is caught.
+                    string message = this.Message;
+                    if (this.InnerException != null)
+                    {
+                        message += " " + this.InnerException;
+                    }
+
+                    Report.Fail(message);
+                }
+            }
+        }
+    }
+}

Microsoft.Validation/Assumes.cs

@@ -0,0 +1,219 @@
+//-----------------------------------------------------------------------
+// <copyright file="Assumes.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Diagnostics;
+    using System.Globalization;
+    using System.Linq;
+
+    /// <summary>
+    /// Common runtime checks that throw internal error exceptions upon failure.
+    /// </summary>
+    internal static partial class Assumes
+    {
+        /// <summary>
+        /// Throws an exception if the specified value is null.
+        /// </summary>
+        /// <typeparam name="T">The type of value to test.</typeparam>
+        [DebuggerStepThrough]
+        public static void NotNull<T>([ValidatedNotNull]T value)
+            where T : class
+        {
+            True(value != null);
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified value is null or empty.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void NotNullOrEmpty([ValidatedNotNull]string value)
+        {
+            NotNull(value);
+            True(value.Length > 0);
+            True(value[0] != '\0');
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified value is null or empty.
+        /// </summary>
+        /// <typeparam name="T">The type of value to test.</typeparam>
+        [DebuggerStepThrough]
+        public static void NotNullOrEmpty<T>([ValidatedNotNull]ICollection<T> values)
+        {
+            Assumes.NotNull(values);
+            Assumes.True(values.Count > 0);
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified value is null or empty.
+        /// </summary>
+        /// <typeparam name="T">The type of value to test.</typeparam>
+        [DebuggerStepThrough]
+        public static void NotNullOrEmpty<T>([ValidatedNotNull]IEnumerable<T> values)
+        {
+            Assumes.NotNull(values);
+            Assumes.True(values.Any());
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified value is not null.
+        /// </summary>
+        /// <typeparam name="T">The type of value to test.</typeparam>
+        [DebuggerStepThrough]
+        public static void Null<T>(T value)
+            where T : class
+        {
+            True(value == null);
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified object is not of a given type.
+        /// </summary>
+        /// <typeparam name="T">The type the value is expected to be.</typeparam>
+        /// <param name="value">The value to test.</param>
+        [DebuggerStepThrough]
+        public static void Is<T>(object value)
+        {
+            True(value is T);
+        }
+
+        /// <summary>
+        /// Throws an internal exception if a condition evaluates to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void False(bool condition, string message = null)
+        {
+            if (condition)
+            {
+                Fail(message);
+            }
+        }
+
+        /// <summary>
+        /// Throws an internal exception if a condition evaluates to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void False(bool condition, string unformattedMessage, object arg1)
+        {
+            if (condition)
+            {
+                Fail(Format(unformattedMessage, arg1));
+            }
+        }
+
+        /// <summary>
+        /// Throws an internal exception if a condition evaluates to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void False(bool condition, string unformattedMessage, params object[] args)
+        {
+            if (condition)
+            {
+                Fail(Format(unformattedMessage, args));
+            }
+        }
+
+        /// <summary>
+        /// Throws an internal exception if a condition evaluates to false.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void True(bool condition, string message = null)
+        {
+            if (!condition)
+            {
+                Fail(message);
+            }
+        }
+
+        /// <summary>
+        /// Throws an internal exception if a condition evaluates to false.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void True(bool condition, string unformattedMessage, object arg1)
+        {
+            if (!condition)
+            {
+                Fail(Format(unformattedMessage, arg1));
+            }
+        }
+
+        /// <summary>
+        /// Throws an internal exception if a condition evaluates to false.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void True(bool condition, string unformattedMessage, params object[] args)
+        {
+            if (!condition)
+            {
+                Fail(Format(unformattedMessage, args));
+            }
+        }
+
+        /// <summary>
+        /// Throws an internal exception.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static Exception NotReachable()
+        {
+            // Keep these two as separate lines of code, so the debugger can come in during the assert dialog
+            // that the exception's constructor displays, and the debugger can then be made to skip the throw
+            // in order to continue the investigation.
+            var exception = new InternalErrorException();
+            throw exception;
+        }
+
+        /// <summary>
+        /// Verifies that a value is not null, and throws an exception about a missing service otherwise.
+        /// </summary>
+        /// <typeparam name="T">The interface of the imported part.</typeparam>
+        [DebuggerStepThrough]
+        public static void Present<T>(T component)
+        {
+            if (component == null)
+            {
+                Type coreType = PrivateErrorHelpers.TrimGenericWrapper(typeof(T), typeof(Lazy<>));
+                Fail(string.Format(CultureInfo.CurrentCulture, Strings.ServiceMissing, coreType.FullName));
+            }
+        }
+
+        /// <summary>
+        /// Throws an internal exception.
+        /// </summary>
+        /// <returns>Nothing, as this method always throws.  The signature allows for "throwing" Fail so C# knows execution will stop.</returns>
+        public static Exception Fail(string message = null, bool showAssert = true)
+        {
+            // Keep these two as separate lines of code, so the debugger can come in during the assert dialog
+            // that the exception's constructor displays, and the debugger can then be made to skip the throw
+            // in order to continue the investigation.
+            var exception = new InternalErrorException(message, showAssert);
+            throw exception;
+        }
+
+        /// <summary>
+        /// Throws an internal exception.
+        /// </summary>
+        /// <returns>Nothing, as this method always throws.  The signature allows for "throwing" Fail so C# knows execution will stop.</returns>
+        public static Exception Fail(string message, Exception innerException, bool showAssert = true)
+        {
+            // Keep these two as separate lines of code, so the debugger can come in during the assert dialog
+            // that the exception's constructor displays, and the debugger can then be made to skip the throw
+            // in order to continue the investigation.
+            var exception = new InternalErrorException(message, innerException, showAssert);
+            throw exception;
+        }
+
+        /// <summary>
+        /// Helper method that formats string arguments.
+        /// </summary>
+        private static string Format(string format, params object[] arguments)
+        {
+            return PrivateErrorHelpers.Format(format, arguments);
+        }
+    }
+}

Microsoft.Validation/EventHandlerExtensions.cs

@@ -0,0 +1,69 @@
+//-----------------------------------------------------------------------
+// <copyright file="EventHandlerExtensions.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+
+    /// <summary>
+    /// Extension methods to make it easier to safely invoke events.
+    /// </summary>
+    internal static class EventHandlerExtensions
+    {
+        /// <summary>
+        /// Invokes any event handlers that are hooked to the specified event.
+        /// </summary>
+        /// <param name="handler">The event.  Null is allowed.</param>
+        /// <param name="sender">The value to pass as the sender of the event.</param>
+        /// <param name="e">Event arguments to include.</param>
+        public static void Raise(this Delegate handler, object sender, EventArgs e)
+        {
+            Requires.NotNull(sender, "sender");
+            Requires.NotNull(e, "e");
+
+            if (handler != null)
+            {
+                handler.DynamicInvoke(sender, e);
+            }
+        }
+
+        /// <summary>
+        /// Invokes any event handlers that are hooked to the specified event.
+        /// </summary>
+        /// <param name="handler">The event.  Null is allowed.</param>
+        /// <param name="sender">The value to pass as the sender of the event.</param>
+        /// <param name="e">Event arguments to include.</param>
+        public static void Raise(this EventHandler handler, object sender, EventArgs e)
+        {
+            Requires.NotNull(sender, "sender");
+            Requires.NotNull(e, "e");
+
+            if (handler != null)
+            {
+                handler(sender, e);
+            }
+        }
+
+        /// <summary>
+        /// Invokes any event handlers that are hooked to the specified event.
+        /// </summary>
+        /// <typeparam name="T">The type of EventArgs.</typeparam>
+        /// <param name="handler">The event.  Null is allowed.</param>
+        /// <param name="sender">The value to pass as the sender of the event.</param>
+        /// <param name="e">Event arguments to include.</param>
+        public static void Raise<T>(this EventHandler<T> handler, object sender, T e)
+            where T : EventArgs
+        {
+            Requires.NotNull(sender, "sender");
+            Requires.NotNull(e, "e");
+
+            if (handler != null)
+            {
+                handler(sender, e);
+            }
+        }
+    }
+}

Microsoft.Validation/IDisposableObservable.cs

@@ -0,0 +1,21 @@
+//-----------------------------------------------------------------------
+// <copyright file="IDisposableObservable.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+
+    /// <summary>
+    /// A disposable object that also provides a safe way to query its disposed status.
+    /// </summary>
+    internal interface IDisposableObservable : IDisposable
+    {
+        /// <summary>
+        /// Gets a value indicating whether this instance has been disposed.
+        /// </summary>
+        bool IsDisposed { get; }
+    }
+}

Microsoft.Validation/Microsoft.Validation.csproj

@@ -0,0 +1,72 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{E016A630-A79B-4B5D-8997-E66581D62B81}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>Microsoft.Validation</RootNamespace>
+    <AssemblyName>Microsoft.Validation</AssemblyName>
+    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Assumes.cs" />
+    <Compile Include="Assumes.InternalErrorException.cs" />
+    <Compile Include="EventHandlerExtensions.cs" />
+    <Compile Include="IDisposableObservable.cs" />
+    <Compile Include="PrivateErrorHelpers.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Report.cs" />
+    <Compile Include="Requires.cs" />
+    <Compile Include="Strings.Designer.cs">
+      <AutoGen>True</AutoGen>
+      <DesignTime>True</DesignTime>
+      <DependentUpon>Strings.resx</DependentUpon>
+    </Compile>
+    <Compile Include="ValidatedNotNullAttribute.cs" />
+    <Compile Include="Verify.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="Strings.resx">
+      <Generator>ResXFileCodeGenerator</Generator>
+      <LastGenOutput>Strings.Designer.cs</LastGenOutput>
+    </EmbeddedResource>
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
+       Other similar extension points exist, see Microsoft.Common.targets.
+  <Target Name="BeforeBuild">
+  </Target>
+  <Target Name="AfterBuild">
+  </Target>
+  -->
+</Project>

Microsoft.Validation/PrivateErrorHelpers.cs

@@ -0,0 +1,50 @@
+//-----------------------------------------------------------------------
+// <copyright file="PrivateErrorHelpers.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Globalization;
+    using System.Linq;
+    using System.Text;
+    using System.Threading.Tasks;
+
+    /// <summary>
+    /// Common utility methods used by the various error detection and reporting classes.
+    /// </summary>
+    internal static class PrivateErrorHelpers
+    {
+        /// <summary>
+        /// Trims away a given surrounding type, returning just the generic type argument,
+        /// if the given type is in fact a generic type with just one type argument and
+        /// the generic type matches a given wrapper type.  Otherwise, it returns the original type.
+        /// </summary>
+        /// <param name="type">The type to trim, or return unmodified.</param>
+        /// <param name="wrapper">The SomeType&lt;&gt; generic type definition to trim away from <paramref name="type"/> if it is present.</param>
+        /// <returns><paramref name="type"/>, if it is not a generic type instance of <paramref name="wrapper"/>; otherwise the type argument.</returns>
+        internal static Type TrimGenericWrapper(Type type, Type wrapper)
+        {
+            Type[] typeArgs;
+            if (type.IsGenericType && type.GetGenericTypeDefinition() == wrapper && (typeArgs = type.GetGenericArguments()).Length == 1)
+            {
+                return typeArgs[0];
+            }
+            else
+            {
+                return type;
+            }
+        }
+
+        /// <summary>
+        /// Helper method that formats string arguments.
+        /// </summary>
+        internal static string Format(string format, params object[] arguments)
+        {
+            return String.Format(CultureInfo.CurrentCulture, format, arguments);
+        }
+    }
+}

Microsoft.Validation/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following 
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("Microsoft.Validation")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("Microsoft Corp.")]
+[assembly: AssemblyProduct("Microsoft.Validation")]
+[assembly: AssemblyCopyright("Copyright © Microsoft Corp. 2012")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible 
+// to COM components.  If you need to access a type in this assembly from 
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("05bbbcbe-7deb-4588-b4dc-7f2a304aca58")]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version 
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers 
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

Microsoft.Validation/Report.cs

@@ -0,0 +1,123 @@
+//-----------------------------------------------------------------------
+// <copyright file="Report.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Diagnostics;
+    using System.Diagnostics.Contracts;
+    using System.Globalization;
+    using System.Linq;
+
+    /// <summary>
+    /// Common runtime checks that trace messages and invoke an assertion failure,
+    /// but does *not* throw exceptions.
+    /// </summary>
+    internal static class Report
+    {
+        /// <summary>
+        /// Verifies that a value is not null, and reports an error about a missing MEF component otherwise.
+        /// </summary>
+        /// <typeparam name="T">The interface of the imported part.</typeparam>
+        [DebuggerStepThrough]
+        internal static void IfNotPresent<T>(T part)
+        {
+            if (part == null)
+            {
+                Type coreType = PrivateErrorHelpers.TrimGenericWrapper(typeof(T), typeof(Lazy<>));
+                if (Environment.GetEnvironmentVariable("CPSUnitTest") != "true")
+                {
+                    Fail(Strings.ServiceMissing, coreType.FullName);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Reports an error if a condition evaluates to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void If(bool condition, string message = null)
+        {
+            if (condition)
+            {
+                Fail(message);
+            }
+        }
+
+        /// <summary>
+        /// Reports an error if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void IfNot(bool condition, string message = null)
+        {
+            if (!condition)
+            {
+                Fail(message);
+            }
+        }
+
+        /// <summary>
+        /// Reports an error if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void IfNot(bool condition, string message, object arg1)
+        {
+            if (!condition)
+            {
+                Fail(PrivateErrorHelpers.Format(message, arg1));
+            }
+        }
+
+        /// <summary>
+        /// Reports an error if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void IfNot(bool condition, string message, object arg1, object arg2)
+        {
+            if (!condition)
+            {
+                Fail(PrivateErrorHelpers.Format(message, arg1, arg2));
+            }
+        }
+
+        /// <summary>
+        /// Reports an error if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void IfNot(bool condition, string message, params object[] args)
+        {
+            if (!condition)
+            {
+                Fail(PrivateErrorHelpers.Format(message, args));
+            }
+        }
+
+        /// <summary>
+        /// Reports a certain failure.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void Fail(string message = null)
+        {
+            if (message == null)
+            {
+                message = "An internal error occurred.";
+            }
+
+            Debug.WriteLine(message);
+            Debug.Fail(message);
+        }
+
+        /// <summary>
+        /// Reports a certain failure.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void Fail(string message, params object[] args)
+        {
+            Fail(PrivateErrorHelpers.Format(message, args));
+        }
+    }
+}

Microsoft.Validation/Requires.cs

@@ -0,0 +1,308 @@
+//-----------------------------------------------------------------------
+// <copyright file="Requires.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+    using System.Collections.Generic;
+    using System.ComponentModel;
+    using System.Diagnostics;
+    using System.Globalization;
+
+    /// <summary>
+    /// Common runtime checks that throw ArgumentExceptions upon failure.
+    /// </summary>
+    internal static class Requires
+    {
+        /// <summary>
+        /// Throws an exception if the specified parameter's value is null.
+        /// </summary>
+        /// <typeparam name="T">The type of the parameter.</typeparam>
+        /// <param name="value">The value of the argument.</param>
+        /// <param name="parameterName">The name of the parameter to include in any thrown exception.</param>
+        /// <returns>The value of the parameter.</returns>
+        /// <exception cref="ArgumentNullException">Thrown if <paramref name="value"/> is <c>null</c></exception>
+        [DebuggerStepThrough]
+        public static T NotNull<T>([ValidatedNotNull]T value, string parameterName)
+            where T : class // ensures value-types aren't passed to a null checking method
+        {
+            if (value == null)
+            {
+                throw new ArgumentNullException(parameterName);
+            }
+
+            return value;
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified parameter's value is IntPtr.Zero.
+        /// </summary>
+        /// <param name="value">The value of the argument.</param>
+        /// <param name="parameterName">The name of the parameter to include in any thrown exception.</param>
+        /// <returns>The value of the parameter.</returns>
+        /// <exception cref="ArgumentNullException">Thrown if <paramref name="value"/> is IntPtr.Zero</exception>
+        [DebuggerStepThrough]
+        public static IntPtr NotNull(IntPtr value, string parameterName)
+        {
+            if (value == IntPtr.Zero)
+            {
+                throw new ArgumentNullException(parameterName);
+            }
+
+            return value;
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified parameter's value is null or empty.
+        /// </summary>
+        /// <param name="value">The value of the argument.</param>
+        /// <param name="parameterName">The name of the parameter to include in any thrown exception.</param>
+        /// <exception cref="ArgumentException">Thrown if <paramref name="value"/> is <c>null</c> or empty.</exception>
+        [DebuggerStepThrough]
+        public static void NotNullOrEmpty([ValidatedNotNull]string value, string parameterName)
+        {
+            // To the guy that is doing random code cleaning: 
+            // Consider the perfomance when changing the code to delegate to NotNull.
+            // In general do not chain call to another function, check first and return as earlier as possible. 
+            if (value == null)
+            {
+                throw new ArgumentNullException(parameterName);
+            }
+
+            if (value.Length == 0 || value[0] == '\0')
+            {
+                throw new ArgumentException(Format(Strings.Argument_EmptyString, parameterName), parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified parameter's value is null, empty, or whitespace.
+        /// </summary>
+        /// <param name="value">The value of the argument.</param>
+        /// <param name="parameterName">The name of the parameter to include in any thrown exception.</param>
+        /// <exception cref="ArgumentException">Thrown if <paramref name="value"/> is <c>null</c> or empty.</exception>
+        [DebuggerStepThrough]
+        public static void NotNullOrWhiteSpace([ValidatedNotNull]string value, string parameterName)
+        {
+            // To the guy that is doing random code cleaning: 
+            // Consider the perfomance when changing the code to delegate to NotNull.
+            // In general do not chain call to another function, check first and return as earlier as possible. 
+            if (value == null)
+            {
+                throw new ArgumentNullException(parameterName);
+            }
+
+            if (value.Length == 0 || value[0] == '\0')
+            {
+                throw new ArgumentException(Format(Strings.Argument_EmptyString, parameterName), parameterName);
+            }
+
+            if (String.IsNullOrWhiteSpace(value))
+            {
+                throw new ArgumentException(Format(Strings.Argument_Whitespace, parameterName));
+            }
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified parameter's value is null,
+        /// has no elements or has an element with a null value.
+        /// </summary>
+        /// <param name="values">The value of the argument.</param>
+        /// <param name="parameterName">The name of the parameter to include in any thrown exception.</param>
+        /// <exception cref="ArgumentException">Thrown if the tested condition is false.</exception>
+        [DebuggerStepThrough]
+        public static void NotNullOrEmpty([ValidatedNotNull]System.Collections.IEnumerable values, string parameterName)
+        {
+            // To the guy that is doing random code cleaning: 
+            // Consider the perfomance when changing the code to delegate to NotNull.
+            // In general do not chain call to another function, check first and return as earlier as possible. 
+            if (values == null)
+            {
+                throw new ArgumentNullException(parameterName);
+            }
+
+            bool hasElements = false;
+            foreach (object value in values)
+            {
+                hasElements = true;
+                break;
+            }
+
+            if (!hasElements)
+            {
+                throw new ArgumentException(Format(Strings.Argument_EmptyArray, parameterName), parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified parameter's value is null,
+        /// has no elements or has an element with a null value.
+        /// </summary>
+        /// <typeparam name="T">The type of the elements in the sequence.</typeparam>
+        /// <param name="values">The value of the argument.</param>
+        /// <param name="parameterName">The name of the parameter to include in any thrown exception.</param>
+        /// <exception cref="ArgumentException">Thrown if the tested condition is false.</exception>
+        [DebuggerStepThrough]
+        public static void NotNullEmptyOrNullElements<T>([ValidatedNotNull]IEnumerable<T> values, string parameterName)
+            where T : class // ensures value-types aren't passed to a null checking method
+        {
+            NotNull(values, parameterName);
+
+            bool hasElements = false;
+            foreach (T value in values)
+            {
+                hasElements = true;
+
+                if (value == null)
+                {
+                    throw new ArgumentException(Format(Strings.Argument_NullElement, parameterName), parameterName);
+                }
+            }
+
+            if (!hasElements)
+            {
+                throw new ArgumentException(Format(Strings.Argument_EmptyArray, parameterName), parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Throws an exception if the specified parameter's value is not null
+        /// <em>and</em> has an element with a null value.
+        /// </summary>
+        /// <typeparam name="T">The type of the elements in the sequence.</typeparam>
+        /// <param name="values">The value of the argument.</param>
+        /// <param name="parameterName">The name of the parameter to include in any thrown exception.</param>
+        /// <exception cref="ArgumentException">Thrown if the tested condition is false.</exception>
+        [DebuggerStepThrough]
+        public static void NullOrNotNullElements<T>(IEnumerable<T> values, string parameterName)
+        {
+            if (values != null)
+            {
+                foreach (T value in values)
+                {
+                    if (value == null)
+                    {
+                        throw new ArgumentException(Format(Strings.Argument_NullElement, parameterName), parameterName);
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="ArgumentOutOfRangeException"/> if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void Range(bool condition, string parameterName, string message = null)
+        {
+            if (!condition)
+            {
+                FailRange(parameterName, message);
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="ArgumentOutOfRangeException"/> if a condition does not evaluate to true.
+        /// </summary>
+        /// <returns>Nothing.  This method always throws.</returns>
+        [DebuggerStepThrough]
+        public static Exception FailRange(string parameterName, string message = null)
+        {
+            if (String.IsNullOrEmpty(message))
+            {
+                throw new ArgumentOutOfRangeException(parameterName);
+            }
+            else
+            {
+                throw new ArgumentOutOfRangeException(parameterName, message);
+            }
+        }
+
+        /// <summary>
+        /// Throws an ArgumentException if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void Argument(bool condition, string parameterName, string message)
+        {
+            if (!condition)
+            {
+                throw new ArgumentException(message, parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Throws an ArgumentException if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void Argument(bool condition, string parameterName, string message, object arg1)
+        {
+            if (!condition)
+            {
+                throw new ArgumentException(Format(message, arg1), parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Throws an ArgumentException if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void Argument(bool condition, string parameterName, string message, object arg1, object arg2)
+        {
+            if (!condition)
+            {
+                throw new ArgumentException(Format(message, arg1, arg2), parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Throws an ArgumentException if a condition does not evaluate to true.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static void Argument(bool condition, string parameterName, string message, params object[] args)
+        {
+            if (!condition)
+            {
+                throw new ArgumentException(Format(message, args), parameterName);
+            }
+        }
+
+        /// <summary>
+        /// Throws an ArgumentException.
+        /// </summary>
+        /// <returns>Nothing.  It always throws.</returns>
+        [DebuggerStepThrough]
+        public static Exception Fail(string message)
+        {
+            throw new ArgumentException(message);
+        }
+
+        /// <summary>
+        /// Throws an ArgumentException.
+        /// </summary>
+        /// <returns>Nothing.  It always throws.</returns>
+        [DebuggerStepThrough]
+        public static Exception Fail(string unformattedMessage, params object[] args)
+        {
+            throw Fail(Format(unformattedMessage, args));
+        }
+
+        /// <summary>
+        /// Throws an ArgumentException.
+        /// </summary>
+        [DebuggerStepThrough]
+        public static Exception Fail(Exception innerException, string unformattedMessage, params object[] args)
+        {
+            throw new ArgumentException(Format(unformattedMessage, args), innerException);
+        }
+
+        /// <summary>
+        /// Helper method that formats string arguments.
+        /// </summary>
+        private static string Format(string format, params object[] arguments)
+        {
+            return PrivateErrorHelpers.Format(format, arguments);
+        }
+    }
+}

Microsoft.Validation/Strings.Designer.cs

@@ -0,0 +1,117 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//     Runtime Version:4.0.30319.17905
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace Microsoft.Validation {
+    using System;
+    
+    
+    /// <summary>
+    ///   A strongly-typed resource class, for looking up localized strings, etc.
+    /// </summary>
+    // This class was auto-generated by the StronglyTypedResourceBuilder
+    // class via a tool like ResGen or Visual Studio.
+    // To add or remove a member, edit your .ResX file then rerun ResGen
+    // with the /str option, or rebuild your VS project.
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")]
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+    [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
+    internal class Strings {
+        
+        private static global::System.Resources.ResourceManager resourceMan;
+        
+        private static global::System.Globalization.CultureInfo resourceCulture;
+        
+        [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
+        internal Strings() {
+        }
+        
+        /// <summary>
+        ///   Returns the cached ResourceManager instance used by this class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Resources.ResourceManager ResourceManager {
+            get {
+                if (object.ReferenceEquals(resourceMan, null)) {
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Microsoft.Validation.Strings", typeof(Strings).Assembly);
+                    resourceMan = temp;
+                }
+                return resourceMan;
+            }
+        }
+        
+        /// <summary>
+        ///   Overrides the current thread's CurrentUICulture property for all
+        ///   resource lookups using this strongly typed resource class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Globalization.CultureInfo Culture {
+            get {
+                return resourceCulture;
+            }
+            set {
+                resourceCulture = value;
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; must contain at least one element..
+        /// </summary>
+        internal static string Argument_EmptyArray {
+            get {
+                return ResourceManager.GetString("Argument_EmptyArray", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; cannot be an empty string (&quot;&quot;) or start with the null character..
+        /// </summary>
+        internal static string Argument_EmptyString {
+            get {
+                return ResourceManager.GetString("Argument_EmptyString", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to &apos;{0}&apos; cannot contain a null (Nothing in Visual Basic) element..
+        /// </summary>
+        internal static string Argument_NullElement {
+            get {
+                return ResourceManager.GetString("Argument_NullElement", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The parameter &quot;{0}&quot; cannot consist entirely of white space characters..
+        /// </summary>
+        internal static string Argument_Whitespace {
+            get {
+                return ResourceManager.GetString("Argument_Whitespace", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to An internal error occurred. Please contact Microsoft Product Support Services..
+        /// </summary>
+        internal static string InternalExceptionMessage {
+            get {
+                return ResourceManager.GetString("InternalExceptionMessage", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot find an instance of the {0} service..
+        /// </summary>
+        internal static string ServiceMissing {
+            get {
+                return ResourceManager.GetString("ServiceMissing", resourceCulture);
+            }
+        }
+    }
+}

Microsoft.Validation/Strings.resx

@@ -0,0 +1,138 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="Argument_EmptyArray" xml:space="preserve">
+    <value>'{0}' must contain at least one element.</value>
+  </data>
+  <data name="Argument_EmptyString" xml:space="preserve">
+    <value>'{0}' cannot be an empty string ("") or start with the null character.</value>
+  </data>
+  <data name="Argument_NullElement" xml:space="preserve">
+    <value>'{0}' cannot contain a null (Nothing in Visual Basic) element.</value>
+  </data>
+  <data name="Argument_Whitespace" xml:space="preserve">
+    <value>The parameter "{0}" cannot consist entirely of white space characters.</value>
+  </data>
+  <data name="InternalExceptionMessage" xml:space="preserve">
+    <value>An internal error occurred. Please contact Microsoft Product Support Services.</value>
+  </data>
+  <data name="ServiceMissing" xml:space="preserve">
+    <value>Cannot find an instance of the {0} service.</value>
+  </data>
+</root>

Microsoft.Validation/ValidatedNotNullAttribute.cs

@@ -0,0 +1,26 @@
+//-----------------------------------------------------------------------
+// <copyright file="ValidatedNotNullAttribute.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+    using System.Diagnostics.CodeAnalysis;
+
+    /// <summary>
+    /// Indicates to Code Analysis that a method validates a particular parameter.
+    /// </summary>
+    [ExcludeFromCodeCoverage]
+    [AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = false)]
+    internal sealed class ValidatedNotNullAttribute : Attribute
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ValidatedNotNullAttribute"/> class.
+        /// </summary>
+        public ValidatedNotNullAttribute()
+        {
+        }
+    }
+}

Microsoft.Validation/Verify.cs

@@ -0,0 +1,192 @@
+//-----------------------------------------------------------------------
+// <copyright file="Verify.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//-----------------------------------------------------------------------
+
+namespace Microsoft.Validation
+{
+    using System;
+    using System.Collections.Generic;
+    using System.Diagnostics;
+    using System.Diagnostics.Contracts;
+    using System.Globalization;
+    using System.Linq;
+    using System.Runtime.InteropServices;
+
+    /// <summary>
+    /// Common runtime checks that throw exceptions upon failure.
+    /// </summary>
+    internal static class Verify
+    {
+        /// <summary>
+        /// Indicates what the desired behavior is in the event of a failure.
+        /// </summary>
+        internal enum ErrorBehavior
+        {
+            /// <summary>
+            /// An exception should be (re)thrown.
+            /// </summary>
+            Throw,
+
+            /// <summary>
+            /// An error should be reported to the user, but then execution flow should resume.
+            /// </summary>
+            Report,
+
+            /// <summary>
+            /// An error should be quietly logged, and then execution flow should resume.
+            /// </summary>
+            Log,
+        }
+
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/> if a condition is false.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void Operation(bool condition, string message)
+        {
+            if (!condition)
+            {
+                throw new InvalidOperationException(message);
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/> if a condition is false.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void Operation(bool condition, string unformattedMessage, object arg1)
+        {
+            if (!condition)
+            {
+                throw new InvalidOperationException(PrivateErrorHelpers.Format(unformattedMessage, arg1));
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/> if a condition is false.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void Operation(bool condition, string unformattedMessage, object arg1, object arg2)
+        {
+            if (!condition)
+            {
+                throw new InvalidOperationException(PrivateErrorHelpers.Format(unformattedMessage, arg1, arg2));
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/> if a condition is false.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void Operation(bool condition, string unformattedMessage, params object[] args)
+        {
+            if (!condition)
+            {
+                throw new InvalidOperationException(PrivateErrorHelpers.Format(unformattedMessage, args));
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/> if a condition is false.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void OperationWithHelp(bool condition, string message, string helpLink)
+        {
+            if (!condition)
+            {
+                var ex = new InvalidOperationException(message);
+                ex.HelpLink = helpLink;
+                throw ex;
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="InvalidOperationException"/>.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void FailOperation(string message, params object[] args)
+        {
+            throw new InvalidOperationException(PrivateErrorHelpers.Format(message, args));
+        }
+
+        /// <summary>
+        /// Throws an <see cref="ObjectDisposedException"/> if an object is disposed.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void NotDisposed(IDisposableObservable disposedValue, string message = null)
+        {
+            Contract.Requires<ArgumentNullException>(disposedValue != null);
+
+            if (disposedValue.IsDisposed)
+            {
+                string objectName = disposedValue != null ? disposedValue.GetType().FullName : String.Empty;
+                if (message != null)
+                {
+                    throw new ObjectDisposedException(objectName, message);
+                }
+                else
+                {
+                    throw new ObjectDisposedException(objectName);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="ObjectDisposedException"/> if a condition is false.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void NotDisposed(bool condition, object disposedValue, string message = null)
+        {
+            if (!condition)
+            {
+                string objectName = disposedValue != null ? disposedValue.GetType().FullName : String.Empty;
+                if (message != null)
+                {
+                    throw new ObjectDisposedException(objectName, message);
+                }
+                else
+                {
+                    throw new ObjectDisposedException(objectName);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Throws an <see cref="ObjectDisposedException"/> if a condition is false.
+        /// </summary>
+        [DebuggerStepThrough]
+        internal static void NotDisposed(bool condition, string message)
+        {
+            if (!condition)
+            {
+                throw new ObjectDisposedException(message);
+            }
+        }
+
+        /// <summary>
+        /// Throws an exception if the given value is negative.
+        /// </summary>
+        /// <param name="hresult">The HRESULT corresponding to the desired exception.</param>
+        /// <param name="ignorePreviousComCalls">If true, prevents <c>ThrowExceptionForHR</c> from returning an exception from a previous COM call and instead always use the HRESULT specified.</param>
+        /// <remarks>
+        /// No exception is thrown for S_FALSE.
+        /// </remarks>
+        [DebuggerStepThrough]
+        internal static void HResult(int hresult, bool ignorePreviousComCalls = false)
+        {
+            if (hresult < 0)
+            {
+                if (ignorePreviousComCalls)
+                {
+                    Marshal.ThrowExceptionForHR(hresult, new IntPtr(-1));
+                }
+                else
+                {
+                    Marshal.ThrowExceptionForHR(hresult);
+                }
+            }
+        }
+    }
+}