Fix Make IViewFor use Generic type (#61)

Author: ChrisPulman

README.md

@@ -304,8 +304,8 @@ public partial class MyReactiveClass
 
 ### IViewFor usage
 
-IVIewFor is used to link a View to a ViewModel, this is used to link the ViewModel to the View in a way that ReactiveUI can use it to bind the ViewModel to the View.
-The ViewModel is passed as a string to the IViewFor Attribute.
+IViewFor is used to link a View to a ViewModel, this is used to link the ViewModel to the View in a way that ReactiveUI can use it to bind the ViewModel to the View.
+The ViewModel is passed as a type to the IViewFor Attribute using generics.
 The class must inherit from a UI Control from any of the following platforms and namespaces:
 - Maui (Microsoft.Maui)
 - WinUI (Microsoft.UI.Xaml)
@@ -317,7 +317,7 @@ The class must inherit from a UI Control from any of the following platforms and
 ```csharp
 using ReactiveUI.SourceGenerators;
 
-[IViewFor(nameof(MyReactiveClass))]
+[IViewFor<MyReactiveClass>]
 public partial class MyReactiveControl : UserControl
 {
     public MyReactiveControl()

src/ReactiveUI.SourceGenerators.Execute.Maui/IViewForTest.cs

@@ -11,6 +11,6 @@ namespace SGReactiveUI.SourceGenerators.Test.Maui
     /// IViewForTest.
     /// </summary>
     /// <seealso cref="NavigationPage" />
-    [IViewFor(nameof(TestViewModel))]
+    [IViewFor<TestViewModel>]
     public partial class IViewForTest : Shell;
 }

src/ReactiveUI.SourceGenerators.Execute/TestViewWinForms.cs

@@ -11,7 +11,7 @@ namespace SGReactiveUI.SourceGenerators.Test
     /// TestViewWinForms.
     /// </summary>
     /// <seealso cref="System.Windows.Forms.Form" />
-    [IViewFor(nameof(TestViewModel))]
+    [IViewFor<TestViewModel>]
     public partial class TestViewWinForms : Form
     {
         /// <summary>

src/ReactiveUI.SourceGenerators.Execute/TestViewWpf.cs

@@ -12,7 +12,7 @@ namespace SGReactiveUI.SourceGenerators.Test;
 /// <summary>
 /// TestView.
 /// </summary>
-[IViewFor(nameof(TestViewModel))]
+[IViewFor<TestViewModel>]
 public partial class TestViewWpf : Window
 {
     /// <summary>

src/ReactiveUI.SourceGenerators/Core/Extensions/ITypeSymbolExtensions.cs

@@ -208,7 +208,7 @@ public static bool HasFullyQualifiedMetadataName(this ITypeSymbol symbol, string
 
         symbol.AppendFullyQualifiedMetadataName(builder);
 
-        return builder.WrittenSpan.SequenceEqual(name.AsSpan());
+        return builder.WrittenSpan.StartsWith(name.AsSpan());
     }
 
     public static bool ContainsFullyQualifiedMetadataName(this ITypeSymbol symbol, string name)

src/ReactiveUI.SourceGenerators/Core/Helpers/AttributeDefinitions.cs

@@ -153,7 +153,7 @@ namespace ReactiveUI.SourceGenerators;
 /// <param name="viewModelType">Type of the view model.</param>
 [global::System.CodeDom.Compiler.GeneratedCode("ReactiveUI.SourceGenerators.IViewForGenerator", "1.1.0.0")]
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
-internal sealed class IViewForAttribute(string? viewModelType) : Attribute;
+internal sealed class IViewForAttribute<T> : Attribute;
 #nullable restore
 #pragma warning restore
 """;

src/ReactiveUI.SourceGenerators/IViewFor/IViewForGenerator.cs

@@ -3,6 +3,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
+using System;
 using System.CodeDom.Compiler;
 using System.Collections.Immutable;
 using System.IO;
@@ -57,8 +58,11 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                             var classSymbol = symbol as INamedTypeSymbol;
                             var classNamespace = classSymbol?.ContainingNamespace.ToString();
                             var className = declaredClass.Identifier.ValueText;
-                            var constructorArgument = attributeData.GetConstructorArguments<string>().First();
-                            if (constructorArgument is string viewModelTypeName)
+                            token.ThrowIfCancellationRequested();
+
+                            var genericArgument = GetGenericType(attributeData);
+                            token.ThrowIfCancellationRequested();
+                            if (genericArgument is string viewModelTypeName && viewModelTypeName.Length > 0)
                             {
                                 token.ThrowIfCancellationRequested();
                                 GatherForwardedAttributes(attributeData, semanticModel, declaredClass, token, out var classAttributesInfo);
@@ -193,4 +197,11 @@ static void GatherForwardedAttributes(
 
         classAttributesInfo = classAttributesInfoBuilder.ToImmutable();
     }
+
+    private static string? GetGenericType(AttributeData attributeData)
+    {
+        var success = attributeData?.AttributeClass?.ToDisplayString();
+        var start = success?.IndexOf('<') + 1 ?? 0;
+        return success?.Substring(start, success.Length - start - 1);
+    }
 }

src/ReactiveUI.SourceGenerators/ReactiveUI.SourceGenerators.csproj

@@ -41,6 +41,9 @@
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.Analyzers" PrivateAssets="all" />
   </ItemGroup>
+  <ItemGroup>
+    <None Remove="bin\Debug\netstandard2.0\\ReactiveUI.SourceGenerators.dll" />
+  </ItemGroup>
 
   <!-- This ensures the library will be packaged as a source generator when we use `dotnet pack` -->
   <ItemGroup>