Address code review feedback - extract method, use GetTagHelpers(), keep '@' in names

- Extract CreateAddUsingResolutionParams method to avoid creating fake FQN
- Use codeDocument.GetTagHelpers() instead of GetRequiredTagHelperContext() to get all tag helpers
- Don't strip '@' from attribute names - descriptor names include it
- Add test for @Bind:after scenario (attribute with parameter)

Tests improved from 3/8 to 5/9 passing. @OnClick and @onchange tests now pass. @Bind tests still failing - need to investigate why @Bind descriptors aren't matching.

Co-authored-by: davidwengier <[email protected]>

Author: Copilot

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/AddUsingsCodeActionResolver.cs

@@ -62,22 +62,26 @@ internal static bool TryCreateAddUsingResolutionParams(string fullyQualifiedName
             return false;
         }
 
+        resolutionParams = CreateAddUsingResolutionParams(@namespace, textDocument, additionalEdit, delegatedDocumentUri);
+        return true;
+    }
+
+    internal static RazorCodeActionResolutionParams CreateAddUsingResolutionParams(string @namespace, VSTextDocumentIdentifier textDocument, TextDocumentEdit? additionalEdit, Uri? delegatedDocumentUri)
+    {
         var actionParams = new AddUsingsCodeActionParams
         {
             Namespace = @namespace,
             AdditionalEdit = additionalEdit
         };
 
-        resolutionParams = new RazorCodeActionResolutionParams
+        return new RazorCodeActionResolutionParams
         {
             TextDocument = textDocument,
             Action = LanguageServerConstants.CodeActions.AddUsing,
             Language = RazorLanguageKind.Razor,
             DelegatedDocumentUri = delegatedDocumentUri,
             Data = actionParams,
         };
-
-        return true;
     }
 
     // Internal for testing

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/UnboundDirectiveAttributeAddUsingCodeActionProvider.cs

@@ -67,30 +67,22 @@ public Task<ImmutableArray<RazorVSInternalCodeAction>> ProvideAsync(RazorCodeAct
         }
 
         // Create the code action
-        // We need to pass a fully qualified name to TryCreateAddUsingResolutionParams,
-        // which will extract the namespace. We append a dummy type name since the method
-        // expects a format like "Namespace.TypeName" and extracts everything before the last dot.
-        if (AddUsingsCodeActionResolver.TryCreateAddUsingResolutionParams(
-            missingNamespace + ".Component", // Append dummy type name for namespace extraction
+        var resolutionParams = AddUsingsCodeActionResolver.CreateAddUsingResolutionParams(
+            missingNamespace,
             context.Request.TextDocument,
             additionalEdit: null,
-            context.DelegatedDocumentUri,
-            out var extractedNamespace,
-            out var resolutionParams))
-        {
-            var addUsingCodeAction = RazorCodeActionFactory.CreateAddComponentUsing(
-                extractedNamespace,
-                newTagName: null,
-                resolutionParams);
+            context.DelegatedDocumentUri);
 
-            // Set high priority and order to show prominently
-            addUsingCodeAction.Priority = VSInternalPriorityLevel.High;
-            addUsingCodeAction.Order = -999;
+        var addUsingCodeAction = RazorCodeActionFactory.CreateAddComponentUsing(
+            missingNamespace,
+            newTagName: null,
+            resolutionParams);
 
-            return Task.FromResult<ImmutableArray<RazorVSInternalCodeAction>>([addUsingCodeAction]);
-        }
+        // Set high priority and order to show prominently
+        addUsingCodeAction.Priority = VSInternalPriorityLevel.High;
+        addUsingCodeAction.Order = -999;
 
-        return SpecializedTasks.EmptyImmutableArray<RazorVSInternalCodeAction>();
+        return Task.FromResult<ImmutableArray<RazorVSInternalCodeAction>>([addUsingCodeAction]);
     }
 
     private static bool TryGetMissingDirectiveAttributeNamespace(
@@ -100,23 +92,23 @@ private static bool TryGetMissingDirectiveAttributeNamespace(
     {
         missingNamespace = null;
 
-        var tagHelperContext = codeDocument.GetRequiredTagHelperContext();
-
-        // Remove the '@' prefix for matching against tag helper descriptors
-        // The attribute name from syntax is "@onclick" but descriptors use "onclick"
-        var nameWithoutAt = attributeName.StartsWith("@") ? attributeName[1..] : attributeName;
+        // Get all tag helpers, not just those in scope, since we want to suggest adding a using
+        var tagHelpers = codeDocument.GetTagHelpers();
+        if (tagHelpers is null)
+        {
+            return false;
+        }
 
-        // For attributes with parameters (e.g., @bind:after becomes bind:after then bind), 
-        // extract just the base attribute name
-        var baseAttributeName = nameWithoutAt;
-        var colonIndex = nameWithoutAt.IndexOf(':');
+        // For attributes with parameters (e.g., @bind:after), extract just the base attribute name
+        var baseAttributeName = attributeName;
+        var colonIndex = attributeName.IndexOf(':');
         if (colonIndex > 0)
         {
-            baseAttributeName = nameWithoutAt[..colonIndex];
+            baseAttributeName = attributeName[..colonIndex];
         }
 
         // Search for matching bound attribute descriptors in all available tag helpers
-        foreach (var tagHelper in tagHelperContext.TagHelpers)
+        foreach (var tagHelper in tagHelpers)
         {
             foreach (var boundAttribute in tagHelper.BoundAttributes)
             {

src/Razor/test/Microsoft.VisualStudioCode.RazorExtension.Test/Endpoints/Shared/CodeActions/UnboundDirectiveAttributeAddUsingTests.cs

@@ -122,4 +122,19 @@ @using Microsoft.AspNetCore.Components.Web
 
         await VerifyCodeActionAsync(input, expected, LanguageServerConstants.CodeActions.AddUsing, addDefaultImports: false);
     }
+
+    [Fact]
+    public async Task AddUsing_BindWithParameter()
+    {
+        var input = """
+            <input @bind:[||]after="HandleAfter" />
+            """;
+
+        var expected = """
+            @using Microsoft.AspNetCore.Components.Web
+            <input @bind:after="HandleAfter" />
+            """;
+
+        await VerifyCodeActionAsync(input, expected, LanguageServerConstants.CodeActions.AddUsing, addDefaultImports: false);
+    }
 }