Decouple scope prefixing from EditForm so it works identically with plain <form>

Author: SteveSandersonMS

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.EventDispatch.cs

@@ -10,7 +10,7 @@ namespace Microsoft.AspNetCore.Components.Endpoints;
 internal partial class EndpointHtmlRenderer
 {
     private readonly Dictionary<(int ComponentId, int FrameIndex), string> _namedSubmitEventsByLocation = new();
-    private readonly Dictionary<string, (int ComponentId, int FrameIndex)> _namedSubmitEventsByAssignedName = new(StringComparer.Ordinal);
+    private readonly Dictionary<string, (int ComponentId, int FrameIndex)> _namedSubmitEventsByScopeQualifiedName = new(StringComparer.Ordinal);
 
     internal Task DispatchSubmitEventAsync(string? handlerName)
     {
@@ -21,7 +21,7 @@ internal Task DispatchSubmitEventAsync(string? handlerName)
             throw new InvalidOperationException("Cannot dispatch the POST request to the Razor Component endpoint, because the POST data does not specify which form is being submitted. To fix this, ensure form elements have an @onsubmit:name attribute with any unique value, or pass a FormHandlerName parameter if using EditForm.");
         }
 
-        if (!_namedSubmitEventsByAssignedName.TryGetValue(handlerName, out var frameLocation))
+        if (!_namedSubmitEventsByScopeQualifiedName.TryGetValue(handlerName, out var frameLocation))
         {
             // This may happen if you deploy an app update and someone still on the old page submits a form,
             // or if you're dynamically building the UI and the submitted form doesn't exist the next time
@@ -47,9 +47,9 @@ private void UpdateNamedEvents(in RenderBatch renderBatch)
                 if (string.Equals(removedEntry.EventType, "onsubmit", StringComparison.Ordinal))
                 {
                     var location = (removedEntry.ComponentId, removedEntry.FrameIndex);
-                    if (_namedSubmitEventsByLocation.Remove(location, out var assignedName))
+                    if (_namedSubmitEventsByLocation.Remove(location, out var scopeQualifiedName))
                     {
-                        _namedSubmitEventsByAssignedName.Remove(assignedName);
+                        _namedSubmitEventsByScopeQualifiedName.Remove(scopeQualifiedName);
                     }
                 }
             }
@@ -62,19 +62,22 @@ private void UpdateNamedEvents(in RenderBatch renderBatch)
             for (var i = 0; i < addedCount; i++)
             {
                 ref var addedEntry = ref addedArray[i];
-                if (string.Equals(addedEntry.EventType, "onsubmit", StringComparison.Ordinal) && addedEntry.AssignedName is string assignedName)
+                if (string.Equals(addedEntry.EventType, "onsubmit", StringComparison.Ordinal)
+                    && addedEntry.AssignedName is string assignedName
+                    && TryGetScopeQualifiedEventName(addedEntry.ComponentId, assignedName, out var scopeQualifiedName))
                 {
                     var location = (addedEntry.ComponentId, addedEntry.FrameIndex);
-                    if (_namedSubmitEventsByAssignedName.TryAdd(assignedName, location))
+
+                    if (_namedSubmitEventsByScopeQualifiedName.TryAdd(scopeQualifiedName, location))
                     {
-                        _namedSubmitEventsByLocation.Add(location, assignedName);
+                        _namedSubmitEventsByLocation.Add(location, scopeQualifiedName);
                     }
                     else
                     {
                         // We could allow multiple events with the same name, since they are all tracked separately. However
                         // this is most likely a mistake on the developer's part so we will consider it an error.
-                        var existingEntry = _namedSubmitEventsByAssignedName[assignedName];
-                        throw new InvalidOperationException($"There is more than one named event with the name '{assignedName}'. Ensure named events have unique names. The following components both use this name:"
+                        var existingEntry = _namedSubmitEventsByScopeQualifiedName[scopeQualifiedName];
+                        throw new InvalidOperationException($"There is more than one named event with the name '{scopeQualifiedName}'. Ensure named events have unique names. The following components both use this name:"
                             + $"\n - {GenerateComponentPath(existingEntry.ComponentId)}"
                             + $"\n - {GenerateComponentPath(addedEntry.ComponentId)}");
                     }

src/Components/Web/src/Forms/AntiforgeryToken.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.AspNetCore.Components.Rendering;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNetCore.Components.Forms;
 
@@ -14,34 +15,34 @@ public class AntiforgeryToken : IComponent
     private bool _hasRendered;
     private AntiforgeryRequestToken? _requestToken;
 
-    [Inject] AntiforgeryStateProvider Antiforgery { get; set; } = default!;
+    [Inject] IServiceProvider Services { get; set; } = default!;
 
     void IComponent.Attach(RenderHandle renderHandle)
     {
         _handle = renderHandle;
-        _requestToken = Antiforgery.GetAntiforgeryToken();
+        _requestToken = Services.GetService<AntiforgeryStateProvider>()?.GetAntiforgeryToken();
     }
 
     Task IComponent.SetParametersAsync(ParameterView parameters)
     {
         if (!_hasRendered)
         {
             _hasRendered = true;
-            _handle.Render(RenderField);
+            if (_requestToken != null)
+            {
+                _handle.Render(RenderField);
+            }
         }
 
         return Task.CompletedTask;
     }
 
     private void RenderField(RenderTreeBuilder builder)
     {
-        if (_requestToken != null)
-        {
-            builder.OpenElement(0, "input");
-            builder.AddAttribute(1, "type", "hidden");
-            builder.AddAttribute(2, "name", _requestToken.FormFieldName);
-            builder.AddAttribute(3, "value", _requestToken.Value);
-            builder.CloseElement();
-        }
+        builder.OpenElement(0, "input");
+        builder.AddAttribute(1, "type", "hidden");
+        builder.AddAttribute(2, "name", _requestToken!.FormFieldName);
+        builder.AddAttribute(3, "value", _requestToken.Value);
+        builder.CloseElement();
     }
 }

src/Components/Web/src/Forms/EditForm.cs

@@ -142,8 +142,7 @@ protected override void BuildRenderTree(RenderTreeBuilder builder)
         // to include the handler and antiforgery token in the post data
         if (MappingContext != null)
         {
-            var combinedFormName = MappingContext.GetCombinedFormName(FormHandlerName) ?? string.Empty;
-            builder.AddNamedEvent(5, "onsubmit", combinedFormName);
+            builder.AddNamedEvent(5, "onsubmit", FormHandlerName ?? string.Empty);
             RenderSSRFormHandlingChildren(builder, 6);
         }
 

src/Components/Web/src/Forms/Mapping/FormMappingContext.cs

@@ -92,7 +92,7 @@ public IEnumerable<FormMappingError> GetAllErrors(string formName)
         _errorsByFormName?.TryGetValue(formName, out var formErrors) == true &&
             formErrors.TryGetValue(key, out var mappingError) ? mappingError.AttemptedValue : null;
 
-    internal string GetCombinedFormName(string? formHandlerName)
+    internal string GetScopeQualifiedFormName(string? formHandlerName)
     {
         if (string.IsNullOrEmpty(Name))
         {

src/Components/Web/src/Forms/Mapping/IFormValueMapper.cs

@@ -12,9 +12,9 @@ public interface IFormValueMapper
     /// Determines whether the specified value type can be mapped.
     /// </summary>
     /// <param name="valueType">The <see cref="Type"/> for the value to map.</param>
-    /// <param name="formName">The form name to map data from or null to only validate the type can be mapped.</param>
+    /// <param name="scopeQualifiedFormName">The form name to map data from or null to only validate the type can be mapped.</param>
     /// <returns><c>true</c> if the value type can be mapped; otherwise, <c>false</c>.</returns>
-    bool CanMap(Type valueType, string? formName = null);
+    bool CanMap(Type valueType, string? scopeQualifiedFormName = null);
 
     /// <summary>
     /// Maps the form value with the specified name to a value of the specified type.

src/Components/Web/src/Forms/Mapping/SupplyParameterFromFormValueProvider.cs

@@ -40,8 +40,8 @@ public bool CanSupplyValue(in CascadingParameterInfo parameterInfo)
         // We also supply values for [SupplyValueFromForm]
         if (_formValueMapper is not null && parameterInfo.Attribute is SupplyParameterFromFormAttribute supplyParameterFromFormAttribute)
         {
-            var combinedFormName = _mappingContext.GetCombinedFormName(supplyParameterFromFormAttribute.Handler);
-            return _formValueMapper.CanMap(parameterInfo.PropertyType, combinedFormName);
+            var scopeQualifiedFormName = _mappingContext.GetScopeQualifiedFormName(supplyParameterFromFormAttribute.Handler);
+            return _formValueMapper.CanMap(parameterInfo.PropertyType, scopeQualifiedFormName);
         }
 
         return false;
@@ -73,15 +73,15 @@ void ICascadingValueSupplier.Unsubscribe(ComponentState subscriber, in Cascading
     internal static object? GetFormPostValue(IFormValueMapper formValueMapper, FormMappingContext? mappingContext, in CascadingParameterInfo parameterInfo, SupplyParameterFromFormAttribute supplyParameterFromFormAttribute)
     {
         Debug.Assert(mappingContext != null);
-        var combinedFormName = mappingContext.GetCombinedFormName(supplyParameterFromFormAttribute.Handler);
+        var scopeQualifiedFormName = mappingContext.GetScopeQualifiedFormName(supplyParameterFromFormAttribute.Handler);
 
         var parameterName = parameterInfo.Attribute.Name ?? parameterInfo.PropertyName;
         var handler = ((SupplyParameterFromFormAttribute)parameterInfo.Attribute).Handler;
         Action<string, FormattableString, string?> errorHandler = string.IsNullOrEmpty(handler) ?
             mappingContext.AddError :
-            (name, message, value) => mappingContext.AddError(combinedFormName, parameterName, message, value);
+            (name, message, value) => mappingContext.AddError(scopeQualifiedFormName, parameterName, message, value);
 
-        var context = new FormValueMappingContext(combinedFormName, parameterInfo.PropertyType, parameterName)
+        var context = new FormValueMappingContext(scopeQualifiedFormName, parameterInfo.PropertyType, parameterName)
         {
             OnError = errorHandler,
             MapErrorToContainer = mappingContext.AttachParentValue

src/Components/Web/src/HtmlRendering/StaticHtmlRenderer.HtmlWriting.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Text.Encodings.Web;
 using Microsoft.AspNetCore.Components.Forms;
 using Microsoft.AspNetCore.Components.RenderTree;
@@ -171,11 +172,8 @@ private void RenderHiddenFieldForNamedSubmitEvent(int componentId, TextWriter ou
             ref var enclosingElementFrame = ref frames.Array[enclosingElementFrameIndex];
             if (string.Equals(enclosingElementFrame.ElementName, "form", StringComparison.OrdinalIgnoreCase))
             {
-                if (FindFormMappingContext(componentId) is { } formMappingContext)
+                if (TryGetScopeQualifiedEventName(componentId, frames.Array[namedEventFramePosition].NamedEventAssignedName, out var combinedFormName))
                 {
-                    var combinedFormName = formMappingContext.GetCombinedFormName(
-                        frames.Array[namedEventFramePosition].NamedEventAssignedName);
-
                     output.Write("<input type=\"hidden\" name=\"handler\" value=\"");
                     _htmlEncoder.Encode(output, combinedFormName);
                     output.Write("\" />");
@@ -184,6 +182,28 @@ private void RenderHiddenFieldForNamedSubmitEvent(int componentId, TextWriter ou
         }
     }
 
+    /// <summary>
+    /// Gets the fully scope-qualified name for a named event, if the component is within
+    /// a <see cref="FormMappingContext"/> (whether or not that mapping context is named).
+    /// </summary>
+    /// <param name="componentId">The ID of the component that defines a named event.</param>
+    /// <param name="eventName">The name assigned to the named event.</param>
+    /// <param name="scopeQualifiedEventName">The scope-qualified event name.</param>
+    /// <returns>A flag to indicate whether a value could be produced.</returns>
+    protected bool TryGetScopeQualifiedEventName(int componentId, string eventName, [NotNullWhen(true)] out string? scopeQualifiedEventName)
+    {
+        if (FindFormMappingContext(componentId) is { } formMappingContext)
+        {
+            scopeQualifiedEventName = formMappingContext.GetScopeQualifiedFormName(eventName);
+            return true;
+        }
+        else
+        {
+            scopeQualifiedEventName = null;
+            return false;
+        }
+    }
+
     private FormMappingContext? FindFormMappingContext(int forComponentId)
     {
         var componentState = GetComponentState(forComponentId);

src/Components/Web/src/PublicAPI.Unshipped.txt

@@ -53,13 +53,14 @@ Microsoft.AspNetCore.Components.Forms.Mapping.FormValueMappingContext.Result.get
 Microsoft.AspNetCore.Components.Forms.Mapping.FormValueMappingContext.SetResult(object? result) -> void
 Microsoft.AspNetCore.Components.Forms.Mapping.FormValueMappingContext.ValueType.get -> System.Type!
 Microsoft.AspNetCore.Components.Forms.Mapping.IFormValueMapper
-Microsoft.AspNetCore.Components.Forms.Mapping.IFormValueMapper.CanMap(System.Type! valueType, string? formName = null) -> bool
+Microsoft.AspNetCore.Components.Forms.Mapping.IFormValueMapper.CanMap(System.Type! valueType, string? scopeQualifiedFormName = null) -> bool
 Microsoft.AspNetCore.Components.Forms.Mapping.IFormValueMapper.Map(Microsoft.AspNetCore.Components.Forms.Mapping.FormValueMappingContext! context) -> void
 Microsoft.AspNetCore.Components.Forms.Mapping.SupplyParameterFromFormServiceCollectionExtensions
 Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer
 Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.BeginRenderingComponent(Microsoft.AspNetCore.Components.IComponent! component, Microsoft.AspNetCore.Components.ParameterView initialParameters) -> Microsoft.AspNetCore.Components.Web.HtmlRendering.HtmlRootComponent
 Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.BeginRenderingComponent(System.Type! componentType, Microsoft.AspNetCore.Components.ParameterView initialParameters) -> Microsoft.AspNetCore.Components.Web.HtmlRendering.HtmlRootComponent
 Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.StaticHtmlRenderer(System.IServiceProvider! serviceProvider, Microsoft.Extensions.Logging.ILoggerFactory! loggerFactory) -> void
+Microsoft.AspNetCore.Components.HtmlRendering.Infrastructure.StaticHtmlRenderer.TryGetScopeQualifiedEventName(int componentId, string! eventName, out string? scopeQualifiedEventName) -> bool
 Microsoft.AspNetCore.Components.RenderTree.WebRenderer.WaitUntilAttachedAsync() -> System.Threading.Tasks.Task!
 Microsoft.AspNetCore.Components.SupplyParameterFromFormAttribute
 Microsoft.AspNetCore.Components.SupplyParameterFromFormAttribute.Handler.get -> string?

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Forms/ActionForm.cs

@@ -52,13 +52,7 @@ void RenderFormContents(RenderTreeBuilder builder, FormMappingContext? bindingCo
 
             if (bindingContext != null)
             {
-                builder.AddNamedEvent(5, "onsubmit", bindingContext.Name);
-
-                builder.OpenElement(2, "input");
-                builder.AddAttribute(3, "type", "hidden");
-                builder.AddAttribute(4, "name", "handler");
-                builder.AddAttribute(5, "value", bindingContext.Name);
-                builder.CloseElement();
+                builder.AddNamedEvent(5, "onsubmit", "");
             }
 
             builder.AddContent(6, ChildContent?.Invoke(bindingContext));