Enable nullability in DesignerActionMethodItem

src/System.Windows.Forms.Design/src/PublicAPI.Shipped.txt

@@ -28,14 +28,14 @@
 ~override System.Windows.Forms.Design.ParentControlDesigner.SnapLines.get -> System.Collections.IList
 ~override System.Windows.Forms.Design.WindowsFormsDesignerOptionService.PopulateOptionCollection(System.ComponentModel.Design.DesignerOptionService.DesignerOptionCollection options) -> void
 ~static System.Windows.Forms.Design.ParentControlDesigner.InvokeCreateTool(System.Windows.Forms.Design.ParentControlDesigner toInvoke, System.Drawing.Design.ToolboxItem tool) -> void
-~System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList actionList, string memberName, string displayName) -> void
-~System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList actionList, string memberName, string displayName, bool includeAsDesignerVerb) -> void
-~System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList actionList, string memberName, string displayName, string category) -> void
-~System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList actionList, string memberName, string displayName, string category, bool includeAsDesignerVerb) -> void
-~System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList actionList, string memberName, string displayName, string category, string description) -> void
-~System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList actionList, string memberName, string displayName, string category, string description, bool includeAsDesignerVerb) -> void
-~System.ComponentModel.Design.DesignerActionMethodItem.RelatedComponent.get -> System.ComponentModel.IComponent
-~System.ComponentModel.Design.DesignerActionMethodItem.RelatedComponent.set -> void
+System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList? actionList, string? memberName, string? displayName) -> void
+System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList? actionList, string? memberName, string? displayName, bool includeAsDesignerVerb) -> void
+System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList? actionList, string? memberName, string? displayName, string? category) -> void
+System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList? actionList, string? memberName, string? displayName, string? category, bool includeAsDesignerVerb) -> void
+System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList? actionList, string? memberName, string? displayName, string? category, string? description) -> void
+System.ComponentModel.Design.DesignerActionMethodItem.DesignerActionMethodItem(System.ComponentModel.Design.DesignerActionList? actionList, string? memberName, string? displayName, string? category, string? description, bool includeAsDesignerVerb) -> void
+System.ComponentModel.Design.DesignerActionMethodItem.RelatedComponent.get -> System.ComponentModel.IComponent?
+System.ComponentModel.Design.DesignerActionMethodItem.RelatedComponent.set -> void
 ~System.Drawing.Design.IToolboxService.AddCreator(System.Drawing.Design.ToolboxItemCreatorCallback creator, string format) -> void
 ~System.Drawing.Design.IToolboxService.AddCreator(System.Drawing.Design.ToolboxItemCreatorCallback creator, string format, System.ComponentModel.Design.IDesignerHost host) -> void
 ~System.Drawing.Design.IToolboxService.AddLinkedToolboxItem(System.Drawing.Design.ToolboxItem toolboxItem, string category, System.ComponentModel.Design.IDesignerHost host) -> void
@@ -83,7 +83,7 @@
 ~System.Windows.Forms.Design.ParentControlDesigner.CreateTool(System.Drawing.Design.ToolboxItem tool, System.Drawing.Rectangle bounds) -> void
 ~System.Windows.Forms.Design.ParentControlDesigner.GetControl(object component) -> System.Windows.Forms.Control
 ~System.Windows.Forms.Design.ParentControlDesigner.MouseDragTool.get -> System.Drawing.Design.ToolboxItem
-~virtual System.ComponentModel.Design.DesignerActionMethodItem.MemberName.get -> string
+virtual System.ComponentModel.Design.DesignerActionMethodItem.MemberName.get -> string?
 ~virtual System.Windows.Forms.Design.ComponentTray.AddComponent(System.ComponentModel.IComponent component) -> void
 ~virtual System.Windows.Forms.Design.ComponentTray.CanCreateComponentFromTool(System.Drawing.Design.ToolboxItem tool) -> bool
 ~virtual System.Windows.Forms.Design.ComponentTray.CanDisplayComponent(System.ComponentModel.IComponent component) -> bool

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/DesignerActionMethodItem.cs

@@ -1,53 +1,118 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
 using System.Reflection;
 
 namespace System.ComponentModel.Design;
 
 public class DesignerActionMethodItem : DesignerActionItem
 {
-    private readonly DesignerActionList _actionList;
-    private MethodInfo _methodInfo;
-
-    public DesignerActionMethodItem(DesignerActionList actionList, string memberName, string displayName, string category, string description, bool includeAsDesignerVerb)
+    private readonly DesignerActionList? _actionList;
+    private MethodInfo? _methodInfo;
+
+    public DesignerActionMethodItem(
+        DesignerActionList? actionList,
+        string? memberName,
+        string? displayName,
+        string? category,
+        string? description,
+        bool includeAsDesignerVerb)
         : base(displayName, category, description)
     {
         _actionList = actionList;
         MemberName = memberName;
         IncludeAsDesignerVerb = includeAsDesignerVerb;
     }
 
-    public DesignerActionMethodItem(DesignerActionList actionList, string memberName, string displayName) : this(actionList, memberName, displayName, null, null, false)
+    public DesignerActionMethodItem(
+        DesignerActionList? actionList,
+        string? memberName,
+        string? displayName)
+        : this(
+            actionList,
+            memberName,
+            displayName,
+            category: null,
+            description: null,
+            includeAsDesignerVerb: false)
     {
     }
 
-    public DesignerActionMethodItem(DesignerActionList actionList, string memberName, string displayName, bool includeAsDesignerVerb) : this(actionList, memberName, displayName, null, null, includeAsDesignerVerb)
+    public DesignerActionMethodItem(
+        DesignerActionList? actionList,
+        string? memberName,
+        string? displayName,
+        bool includeAsDesignerVerb)
+        : this(
+            actionList,
+            memberName,
+            displayName,
+            category: null,
+            description: null,
+            includeAsDesignerVerb)
     {
     }
 
-    public DesignerActionMethodItem(DesignerActionList actionList, string memberName, string displayName, string category) : this(actionList, memberName, displayName, category, null, false)
+    public DesignerActionMethodItem(
+        DesignerActionList? actionList,
+        string? memberName,
+        string? displayName,
+        string? category)
+        : this(
+            actionList,
+            memberName,
+            displayName,
+            category,
+            description: null,
+            includeAsDesignerVerb: false)
     {
     }
 
-    public DesignerActionMethodItem(DesignerActionList actionList, string memberName, string displayName, string category, bool includeAsDesignerVerb) : this(actionList, memberName, displayName, category, null, includeAsDesignerVerb)
+    public DesignerActionMethodItem(
+        DesignerActionList? actionList,
+        string? memberName,
+        string? displayName,
+        string? category,
+        bool includeAsDesignerVerb)
+        : this(
+            actionList,
+            memberName,
+            displayName,
+            category,
+            description: null,
+            includeAsDesignerVerb)
     {
     }
 
-    public DesignerActionMethodItem(DesignerActionList actionList, string memberName, string displayName, string category, string description) : this(actionList, memberName, displayName, category, description, false)
+    public DesignerActionMethodItem(
+        DesignerActionList? actionList,
+        string? memberName,
+        string? displayName,
+        string? category,
+        string? description)
+        : this(
+            actionList,
+            memberName,
+            displayName,
+            category,
+            description,
+            includeAsDesignerVerb: false)
     {
     }
 
-    public virtual string MemberName { get; }
+    public virtual string? MemberName { get; }
 
-    public IComponent RelatedComponent { get; set; }
+    public IComponent? RelatedComponent { get; set; }
 
     public virtual bool IncludeAsDesignerVerb { get; }
 
     public virtual void Invoke()
     {
+        if (MemberName is null)
+        {
+            throw new InvalidOperationException();
+        }
+
         _methodInfo ??= _actionList?.GetType()?.GetMethod(MemberName, BindingFlags.Default | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
 
         if (_methodInfo is null)
@@ -61,7 +126,7 @@ public virtual void Invoke()
     // this is only use for verbs so that a designer action method item can
     // be converted to a verb. Verbs use an EventHandler to call their invoke
     // so we need a way to translate the EventHandler Invoke into ou own Invoke
-    internal void Invoke(object sender, EventArgs args)
+    internal void Invoke(object? sender, EventArgs args)
     {
         Invoke();
     }

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/DesignerActionVerbItem.cs

@@ -7,7 +7,8 @@ internal class DesignerActionVerbItem : DesignerActionMethodItem
 {
     private readonly DesignerVerb _targetVerb;
 
-    public DesignerActionVerbItem(DesignerVerb verb) : base(null, null, null)
+    public DesignerActionVerbItem(DesignerVerb verb)
+        : base(actionList: null, memberName: null, displayName: null)
     {
         Debug.Assert(verb is not null, "All callers check whether the verb is null.");
         _targetVerb = verb;

src/System.Windows.Forms.Design/tests/UnitTests/System/ComponentModel/Design/DesignerActionMethodItemTests.cs

@@ -209,6 +209,7 @@ public void Invoke_NullActionList_ThrowsInvalidOperationException()
     }
 
     [Theory]
+    [InlineData(null)]
     [InlineData("")]
     [InlineData("NoSuchMember")]
     [InlineData(nameof(SubDesignerActionList.StaticMethod))]
@@ -219,14 +220,6 @@ public void Invoke_NoSuchMemberName_ThrowsInvalidOperationException(string membe
         Assert.Throws<InvalidOperationException>(item.Invoke);
     }
 
-    [Fact]
-    public void Invoke_NullMemberName_ThrowsArgumentNullException()
-    {
-        SubDesignerActionList list = new();
-        DesignerActionMethodItem item = new(list, null, "displayName", "category", "description");
-        Assert.Throws<ArgumentNullException>("name", item.Invoke);
-    }
-
     [Fact]
     public void Invoke_MemberWithParameters_ThrowsTargetParameterCountException()
     {