Fix nullability warnings (samples/snippets/standard) (#35190)

samples/snippets/standard/assembly/unloading/complex_assemblyloadcontext.cs

@@ -12,9 +12,9 @@ namespace complex
             _resolver = new AssemblyDependencyResolver(mainAssemblyToLoadPath);
         }
 
-        protected override Assembly Load(AssemblyName name)
+        protected override Assembly? Load(AssemblyName name)
         {
-            string assemblyPath = _resolver.ResolveAssemblyToPath(name);
+            string? assemblyPath = _resolver.ResolveAssemblyToPath(name);
             if (assemblyPath != null)
             {
                 return LoadFromAssemblyPath(assemblyPath);

samples/snippets/standard/assembly/unloading/simple_example.cs

@@ -12,7 +12,7 @@ namespace simple
         {
         }
 
-        protected override Assembly Load(AssemblyName name)
+        protected override Assembly? Load(AssemblyName name)
         {
             return null;
         }
@@ -23,7 +23,7 @@ namespace simple
     {
         // <Snippet2>
         [MethodImpl(MethodImplOptions.NoInlining)]
-        static int ExecuteAndUnload(string assemblyPath, out WeakReference alcWeakRef)
+        static void ExecuteAndUnload(string assemblyPath, out WeakReference alcWeakRef)
         {
             // <Snippet3>
             var alc = new TestAssemblyLoadContext();
@@ -34,14 +34,12 @@ namespace simple
 
             // <Snippet4>
             var args = new object[1] {new string[] {"Hello"}};
-            int result = (int) a.EntryPoint.Invoke(null, args);
+            _ = a.EntryPoint?.Invoke(null, args);
             // </Snippet4>
 
             // <Snippet5>
             alc.Unload();
             // </Snippet5>
-
-            return result;
         }
         // </Snippet2>
 
@@ -49,7 +47,7 @@ namespace simple
         {
             // <Snippet6>
             WeakReference testAlcWeakRef;
-            int result = ExecuteAndUnload("absolute/path/to/your/assembly", out testAlcWeakRef);
+            ExecuteAndUnload("absolute/path/to/your/assembly", out testAlcWeakRef);
             // </Snippet6>
 
             // <Snippet7>

samples/snippets/standard/assembly/unloading/unloadability_issues_example_main.cs

@@ -10,7 +10,7 @@ namespace example
         public TestAssemblyLoadContext() : base(true)
         {
         }
-        protected override Assembly Load(AssemblyName name)
+        protected override Assembly? Load(AssemblyName name)
         {
             return null;
         }
@@ -18,19 +18,20 @@ namespace example
 
     class TestInfo
     {
-        public TestInfo(MethodInfo mi)
+        public TestInfo(MethodInfo? mi)
         {
-            entryPoint = mi;
+            _entryPoint = mi;
         }
-        MethodInfo entryPoint;
+
+        MethodInfo? _entryPoint;
     }
 
     class Program
     {
-        static TestInfo entryPoint;
+        static TestInfo? entryPoint;
 
         [MethodImpl(MethodImplOptions.NoInlining)]
-        static int ExecuteAndUnload(string assemblyPath, out WeakReference testAlcWeakRef, out MethodInfo testEntryPoint)
+        static int ExecuteAndUnload(string assemblyPath, out WeakReference testAlcWeakRef, out MethodInfo? testEntryPoint)
         {
             var alc = new TestAssemblyLoadContext();
             testAlcWeakRef = new WeakReference(alc);
@@ -45,21 +46,21 @@ namespace example
 
             var args = new object[1] {new string[] {"Hello"}};
 
-            // Issue preventing unloading #1 - we keep MethodInfo of a method for an assembly loaded into the TestAssemblyLoadContext in a static variable
+            // Issue preventing unloading #1 - we keep MethodInfo of a method
+            // for an assembly loaded into the TestAssemblyLoadContext in a static variable.
             entryPoint = new TestInfo(a.EntryPoint);
             testEntryPoint = a.EntryPoint;
 
-            int result = (int)a.EntryPoint.Invoke(null, args);
+            var oResult = a.EntryPoint?.Invoke(null, args);
             alc.Unload();
-
-            return result;
+            return (oResult is int result) ? result : -1;
         }
 
         static void Main(string[] args)
         {
             WeakReference testAlcWeakRef;
             // Issue preventing unloading #2 - we keep MethodInfo of a method for an assembly loaded into the TestAssemblyLoadContext in a local variable
-            MethodInfo testEntryPoint;
+            MethodInfo? testEntryPoint;
             int result = ExecuteAndUnload(@"absolute/path/to/test.dll", out testAlcWeakRef, out testEntryPoint);
 
             for (int i = 0; testAlcWeakRef.IsAlive && (i < 10); i++)

samples/snippets/standard/assembly/unloading/unloadability_issues_example_test.cs

@@ -6,7 +6,6 @@ namespace test
 {
     class Test
     {
-        string message = "Hello";
     }
 
     class Program

samples/snippets/standard/assembly/unloading/unloading.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <StartupObject>test.Program</StartupObject>
   </PropertyGroup>
 

samples/snippets/standard/buffers/memory-t/owner-using/owner-using.cs

@@ -8,17 +8,25 @@ class Example
         using (IMemoryOwner<char> owner = MemoryPool<char>.Shared.Rent())
         {
             Console.Write("Enter a number: ");
-            try {
-                var value = Int32.Parse(Console.ReadLine());
+            try
+            {
+                string? s = Console.ReadLine();
+
+                if (s is null)
+                    return;
+
+                var value = Int32.Parse(s);
 
                 var memory = owner.Memory;
                 WriteInt32ToBuffer(value, memory);
                 DisplayBufferToConsole(memory.Slice(0, value.ToString().Length));
             }
-            catch (FormatException) {
+            catch (FormatException)
+            {
                 Console.WriteLine("You did not enter a valid number.");
             }
-            catch (OverflowException) {
+            catch (OverflowException)
+            {
                 Console.WriteLine($"You entered a number less than {Int32.MinValue:N0} or greater than {Int32.MaxValue:N0}.");
             }
         }

samples/snippets/standard/buffers/memory-t/owner-using/owner-using.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>Visual_Studio_Projects</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/buffers/memory-t/owner/owner.cs

@@ -8,8 +8,14 @@ class Example
         IMemoryOwner<char> owner = MemoryPool<char>.Shared.Rent();
 
         Console.Write("Enter a number: ");
-	    try {
-            var value = Int32.Parse(Console.ReadLine());
+        try
+        {
+            string? s = Console.ReadLine();
+
+            if (s is null)
+                return;
+
+            var value = Int32.Parse(s);
 
             var memory = owner.Memory;
 
@@ -17,13 +23,16 @@ class Example
 
             DisplayBufferToConsole(owner.Memory.Slice(0, value.ToString().Length));
         }
-        catch (FormatException) {
+        catch (FormatException)
+        {
             Console.WriteLine("You did not enter a valid number.");
         }
-        catch (OverflowException) {
+        catch (OverflowException)
+        {
             Console.WriteLine($"You entered a number less than {Int32.MinValue:N0} or greater than {Int32.MaxValue:N0}.");
         }
-        finally {
+        finally
+        {
             owner?.Dispose();
         }
     }

samples/snippets/standard/buffers/memory-t/owner/owner.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>Visual_Studio_Projects</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/buffers/memory-t/ownerless/ownerless.cs

@@ -7,7 +7,12 @@ class Example
         Memory<char> memory = new char[64];
 
         Console.Write("Enter a number: ");
-	    var value = Int32.Parse(Console.ReadLine());
+        string? s = Console.ReadLine();
+
+        if (s is null)
+            return;
+
+	    var value = Int32.Parse(s);
 
         WriteInt32ToBuffer(value, memory);
         DisplayBufferToConsole(memory);

samples/snippets/standard/buffers/memory-t/ownerless/ownerless.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>Visual_Studio_Projects</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/buffers/memory-t/task-returning-async/project.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>task_returning_async</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/buffers/memory-t/task-returning-async/task-returning-async.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Buffers;
 using System.IO;
 using System.Threading.Tasks;
@@ -28,7 +28,12 @@ public class Example
             var span = memory.Span;
             while (true)
             {
-                int value = Int32.Parse(Console.ReadLine());
+                string? s = Console.ReadLine();
+
+                if (s is null)
+                    return;
+
+                int value = Int32.Parse(s);
                 if (value < 0)
                     return;
 

samples/snippets/standard/buffers/memory-t/task-returning/task-returning.cs

@@ -11,7 +11,8 @@ public class Example
     {
         string defensiveCopy = message.ToString();
         // Run in the background so that we don't block the main thread while performing IO.
-        Task.Run(() => {
+        Task.Run(() =>
+        {
             StreamWriter sw = File.AppendText(@".\input-numbers.dat");
             sw.WriteLine(defensiveCopy);
             sw.Flush();
@@ -28,7 +29,12 @@ public class Example
             var span = memory.Span;
             while (true)
             {
-                int value = Int32.Parse(Console.ReadLine());
+                string? s = Console.ReadLine();
+
+                if (s is null)
+                    return;
+
+                int value = Int32.Parse(s);
                 if (value < 0)
                     return;
 

samples/snippets/standard/buffers/memory-t/task-returning/task-returning.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>void_returning</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/buffers/memory-t/task-returning2/task-returning2.cs

@@ -27,7 +27,12 @@ public class Example
             var span = memory.Span;
             while (true)
             {
-                int value = Int32.Parse(Console.ReadLine());
+                string? s = Console.ReadLine();
+
+                if (s is null)
+                    return;
+
+                int value = Int32.Parse(s);
                 if (value < 0)
                     return;
 

samples/snippets/standard/buffers/memory-t/task-returning2/task-returning2.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>void_returning</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/buffers/memory-t/void-returning-async/void-returning-async.cs

@@ -28,7 +28,12 @@ public class Example
             var span = memory.Span;
             while (true)
             {
-                int value = Int32.Parse(Console.ReadLine());
+                string? s = Console.ReadLine();
+
+                if (s is null)
+                    return;
+
+                int value = Int32.Parse(s);
                 if (value < 0)
                     return;
 

samples/snippets/standard/buffers/memory-t/void-returning-async/void-returning-async.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>void_returning</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/buffers/memory-t/void-returning/void-returning.cs

@@ -16,7 +16,12 @@ public class Example
             var span = memory.Span;
             while (true)
             {
-                int value = Int32.Parse(Console.ReadLine());
+                string? s = Console.ReadLine();
+
+                if (s is null)
+                    return;
+
+                int value = Int32.Parse(s);
                 if (value < 0)
                     return;
 

samples/snippets/standard/buffers/memory-t/void-returning/void-returning.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>void_returning</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/data/sqlite/AggregateFunctionSample/AggregateFunctionSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/AsyncSample/AsyncSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/BackupSample/BackupSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/BackupSample/Program.cs

@@ -38,7 +38,7 @@ namespace BackupSample
                 FROM data
                 LIMIT 1
             ";
-            var value = (string)selectCommand.ExecuteScalar();
+            var value = (string?)selectCommand.ExecuteScalar();
             Console.WriteLine(value);
 
             // Clean up

samples/snippets/standard/data/sqlite/BatchingSample/BatchingSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/BulkInsertSample/BulkInsertSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/CollationSample/CollationSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/CollationSample/Program.cs

@@ -35,7 +35,8 @@ namespace CollationSample
                 FROM greek_letter
                 WHERE value = 'λ' COLLATE NOCASE
             ";
-            var count = (long)queryCommand.ExecuteScalar();
+            var oCount = queryCommand.ExecuteScalar();
+            var count = (oCount is not null) ? (int)oCount : -1;
             #endregion
 
             Console.WriteLine($"Results: {count}");

samples/snippets/standard/data/sqlite/DapperSample/DapperSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/DapperSample/Program.cs

@@ -36,7 +36,7 @@ namespace DapperSample
     {
         public bool Boolean { get; set; }
         public byte Byte { get; set; }
-        public byte[] ByteArray { get; set; }
+        public byte[]? ByteArray { get; set; }
         public char Char { get; set; }
         public DateTime DateTime { get; set; }
         public DateTimeOffset DateTimeOffset { get; set; }
@@ -48,7 +48,7 @@ namespace DapperSample
         public long Int64 { get; set; }
         public sbyte SByte { get; set; }
         public short Int16 { get; set; }
-        public string String { get; set; }
+        public string? String { get; set; }
         public TimeSpan TimeSpan { get; set; }
         public uint UInt32 { get; set; }
         public ulong UInt64 { get; set; }

samples/snippets/standard/data/sqlite/DateAndTimeSample/DateAndTimeSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/DateAndTimeSample/Program.cs

@@ -81,7 +81,8 @@ namespace DateAndTimeSample
             // Convert TimeSpan to days instead of text
             command.Parameters.AddWithValue("$expected", expected).SqliteType = SqliteType.Real;
             #endregion
-            var count = (long)command.ExecuteScalar();
+            var oCount = command.ExecuteScalar();
+            var count = (oCount is not null) ? (long)oCount : -1;
             Console.WriteLine($"{count} tasks are overdue.");
         }
     }

samples/snippets/standard/data/sqlite/DeferredTransactionSample/DeferredTransactionSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/DirtyReadSample/DirtyReadSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/EncryptionSample/EncryptionSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/ExtensionsSample/ExtensionsSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/HelloWorldSample/HelloWorldSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/InteropSample/InteropSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/RegularExpressionSample/RegularExpressionSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/ResultMetadataSample/ResultMetadataSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/SavepointSample/SavepointSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/ScalarFunctionSample/ScalarFunctionSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/SqliteProviderSample/SqliteProviderSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/StreamingSample/StreamingSample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/data/sqlite/SystemLibrarySample/SystemLibrarySample.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/snippets/standard/datetime/calendars/current-era/cs/work-with-calendars.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>work_with_calendars</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/datetime/calendars/gannen/cs/gannen-fmt.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>gannen_fmt</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/datetime/calendars/gregorian/cs/cs.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
 </Project>

samples/snippets/standard/datetime/calendars/relaxed-range/cs/cs.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
 </Project>

samples/snippets/standard/datetime/calendars/specify-era/cs/work-with-calendars.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>work_with_calendars</RootNamespace>
   </PropertyGroup>
 

samples/snippets/standard/interop/pinvoke/import-resolver/cs.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
 </Project>

samples/snippets/standard/io/io-exceptions/cs/io-exceptions.cs

@@ -6,7 +6,7 @@ class Program
 {
     static void Main()
     {
-	    var sw = OpenStream(@".\textfile.txt");
+        var sw = OpenStream(@".\textfile.txt");
         if (sw is null)
             return;
         sw.WriteLine("This is the first line.");
@@ -14,39 +14,49 @@ class Program
         sw.Close();
     }
 
-   static StreamWriter OpenStream(string path)
-   {
-        if (path is null) {
+    static StreamWriter? OpenStream(string path)
+    {
+        if (path is null)
+        {
             Console.WriteLine("You did not supply a file path.");
             return null;
         }
 
-        try {
+        try
+        {
             var fs = new FileStream(path, FileMode.CreateNew);
             return new StreamWriter(fs);
         }
-        catch (FileNotFoundException) {
+        catch (FileNotFoundException)
+        {
             Console.WriteLine("The file or directory cannot be found.");
         }
-        catch (DirectoryNotFoundException) {
+        catch (DirectoryNotFoundException)
+        {
             Console.WriteLine("The file or directory cannot be found.");
         }
-        catch (DriveNotFoundException) {
+        catch (DriveNotFoundException)
+        {
             Console.WriteLine("The drive specified in 'path' is invalid.");
         }
-        catch (PathTooLongException) {
+        catch (PathTooLongException)
+        {
             Console.WriteLine("'path' exceeds the maximum supported path length.");
         }
-        catch (UnauthorizedAccessException) {
+        catch (UnauthorizedAccessException)
+        {
             Console.WriteLine("You do not have permission to create this file.");
         }
-        catch (IOException e) when ((e.HResult & 0x0000FFFF) == 32 ) {
+        catch (IOException e) when ((e.HResult & 0x0000FFFF) == 32)
+        {
             Console.WriteLine("There is a sharing violation.");
         }
-        catch (IOException e) when ((e.HResult & 0x0000FFFF) == 80) {
+        catch (IOException e) when ((e.HResult & 0x0000FFFF) == 80)
+        {
             Console.WriteLine("The file already exists.");
         }
-        catch (IOException e) {
+        catch (IOException e)
+        {
             Console.WriteLine($"An exception occurred:\nError code: " +
                               $"{e.HResult & 0x0000FFFF}\nMessage: {e.Message}");
         }

samples/snippets/standard/io/io-exceptions/cs/io-exceptions.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
 </Project>