Fix for netstandard projects (#1382)

* [XamlC] treat netstandard types as mscorlib (#1281)

If the end user project type differs from Core's type, the compiler can
be confused while comparing base styles, like System.Double.

this fixes that by assuming System.Runtime, mscorlib and netstnadard
types are equivalent (because they are)

* [C] fix an issue with netstandard when context type is object (#1282)

* [XamlC] fix typo

fixes #1316, fixes #1368

Xamarin.Forms.Build.Tasks/TypeReferenceExtensions.cs

@@ -24,11 +24,16 @@ namespace Xamarin.Forms.Build.Tasks
 			if (x.FullName != y.FullName)
 				return false;
 			var xasm = GetAssembly(x);
-			if (xasm.StartsWith("System.Runtime", StringComparison.Ordinal) || xasm.StartsWith("mscorlib", StringComparison.Ordinal))
-				xasm = "mscorlib";
 			var yasm = GetAssembly(y);
-			if (yasm.StartsWith("System.Runtime", StringComparison.Ordinal) || yasm.StartsWith("mscorlib", StringComparison.Ordinal))
-				yasm = "mscorlib";
+
+			//standard types comes from either mscorlib. System.Runtime or netstandard. Assume they are equivalent
+			if (   (xasm.StartsWith("System.Runtime", StringComparison.Ordinal)
+					|| xasm.StartsWith("mscorlib", StringComparison.Ordinal)
+					|| xasm.StartsWith("netstandard", StringComparison.Ordinal))
+				&& (yasm.StartsWith("System.Runtime", StringComparison.Ordinal)
+					|| yasm.StartsWith("mscorlib", StringComparison.Ordinal)
+					|| yasm.StartsWith("netstandard", StringComparison.Ordinal)))
+				return true;
 			return xasm == yasm;
 		}
 

Xamarin.Forms.Core/BindingExpression.cs

@@ -316,11 +316,7 @@ namespace Xamarin.Forms
 				}
 			}
 			else
-			{
-				property = sourceType.GetDeclaredProperty(part.Content);
-				if (property == null)
-					property = sourceType.BaseType.GetProperty(part.Content);
-			}
+				property = sourceType.GetDeclaredProperty(part.Content) ?? sourceType.BaseType?.GetProperty(part.Content);
 
 			if (property != null)
 			{