[Blazor] Bind after changes (#363)

Due to the way we decided to implement bind get,set,after, customers can run into situations where their components render many more times than expected, which results in confusion and performance degradation.

This was due to the fact that we chose to rely on EventCallback to implement this feature and we did not realize there were some side effects associated with it.

The APIs we are adding bypass the whole EventCallback infrastructure (simplifying the implementation too) and fix the issue.

This change updates the compiler to rely on the new runtime APIs

(cherry picked from commit 9ce52f1afbfb819fc8499a590385200b97b13f33)

src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentBindLoweringPass.cs

@@ -855,21 +855,21 @@ private void RewriteNodesForComponentEventCallbackBind(
         else if (setter == null && after != null)
         {
             // bind:after only
-            var afterToEventCallback = $"global::{ComponentsApi.EventCallback.FactoryAccessor}.{ComponentsApi.EventCallbackFactory.CreateMethod}(this, callback: {after.Content})";
+            var afterContentInvocation = $"{ComponentsApi.RuntimeHelpers.InvokeAsynchronousDelegate}(callback: {after.Content})";
             changeExpressionTokens.Add(new IntermediateToken()
             {
-                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: __value => {{ {original.Content} = __value; return {afterToEventCallback}.InvokeAsync(); }}, value: {original.Content})",
+                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredBindSetter}(callback: __value => {{ {original.Content} = __value; return {afterContentInvocation}; }}, value: {original.Content})",
                 Kind = TokenKind.CSharp
             });
         }
         else
         {
             // bind:set and bind:after create the code even though we disallow this combination through a diagnostic
-            var setToEventCallback = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: {setter.Content}, value: {original.Content})";
-            var afterToEventCallback = $"global::{ComponentsApi.EventCallback.FactoryAccessor}.{ComponentsApi.EventCallbackFactory.CreateMethod}(this, callback: {after.Content})";
+            var setToEventCallback = $"{ComponentsApi.RuntimeHelpers.CreateInferredBindSetter}(callback: {setter.Content}, value: {original.Content})";
+            var afterContentInvocation = $"{ComponentsApi.RuntimeHelpers.InvokeAsynchronousDelegate}(callback: {after.Content})";
             changeExpressionTokens.Add(new IntermediateToken()
             {
-                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: async __value => {{ await {setToEventCallback}.InvokeAsync(); await {afterToEventCallback}.InvokeAsync(); }}, value: {original.Content})",
+                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: async __value => {{ await {setToEventCallback}; await {afterContentInvocation}; }}, value: {original.Content})",
                 Kind = TokenKind.CSharp
             });
         }
@@ -966,28 +966,28 @@ private void RewriteNodesForElementEventCallbackBind(
             // bind:set only
             changeExpressionTokens.Add(new IntermediateToken()
             {
-                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: {setter.Content}, value: {original.Content})",
+                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredBindSetter}(callback: {setter.Content}, value: {original.Content})",
                 Kind = TokenKind.CSharp
             });
         }
         else if (setter == null && after != null)
         {
             // bind:after only
-            var afterToEventCallback = $"global::{ComponentsApi.EventCallback.FactoryAccessor}.{ComponentsApi.EventCallbackFactory.CreateMethod}(this, callback: {after.Content})";
+            var afterContentInvocation = $"{ComponentsApi.RuntimeHelpers.InvokeAsynchronousDelegate}(callback: {after.Content})";
             changeExpressionTokens.Add(new IntermediateToken()
             {
-                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: __value => {{ {original.Content} = __value; return {afterToEventCallback}.InvokeAsync(); }}, value: {original.Content})",
+                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredBindSetter}(callback: __value => {{ {original.Content} = __value; return {afterContentInvocation}; }}, value: {original.Content})",
                 Kind = TokenKind.CSharp
             });
         }
         else
         {
             // bind:set and bind:after create the code even though we disallow this combination through a diagnostic
-            var setToEventCallback = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: {setter.Content}, value: {original.Content})";
-            var afterToEventCallback = $"global::{ComponentsApi.EventCallback.FactoryAccessor}.{ComponentsApi.EventCallbackFactory.CreateMethod}(this, callback: {after.Content})";
+            var setterContentInvocation = $"{ComponentsApi.RuntimeHelpers.CreateInferredBindSetter}(callback: {setter.Content}, value: {original.Content})";
+            var afterContentInvocation = $"{ComponentsApi.RuntimeHelpers.InvokeAsynchronousDelegate}(callback: {after.Content})";
             changeExpressionTokens.Add(new IntermediateToken()
             {
-                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: async __value => {{ await {setToEventCallback}.InvokeAsync(); await {afterToEventCallback}.InvokeAsync(); }}, value: {original.Content})",
+                Content = $"{ComponentsApi.RuntimeHelpers.CreateInferredEventCallback}(this, callback: async __value => {{ await {setterContentInvocation}(); await {afterContentInvocation}; }}, value: {original.Content})",
                 Kind = TokenKind.CSharp
             });
         }

src/Compiler/Microsoft.AspNetCore.Razor.Language/src/Components/ComponentsApi.cs

@@ -109,6 +109,7 @@ public static class RuntimeHelpers
     {
         public const string TypeCheck = "global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck";
         public const string CreateInferredEventCallback = "global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.CreateInferredEventCallback";
+        public const string CreateInferredBindSetter = "global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.CreateInferredBindSetter";
         public const string InvokeSynchronousDelegate = "global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.InvokeSynchronousDelegate";
         public const string InvokeAsynchronousDelegate = "global::Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.InvokeAsynchronousDelegate";
     }