Ports DataMemberFieldEditor to the Runtime

src/System.Design/src/System.Design.Forwards.cs

@@ -8,6 +8,7 @@
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.BindingSourceDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.ColumnHeaderCollectionEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.DataMemberFieldConverter))]
+[assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.DataMemberFieldEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.DataGridViewCellStyleEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.DataGridViewColumnTypeEditor))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.DataSourceListEditor))]

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

@@ -0,0 +1,59 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#nullable enable
+
+using System.ComponentModel;
+using System.Drawing.Design;
+
+namespace System.Windows.Forms.Design;
+
+internal class DataMemberFieldEditor : UITypeEditor
+{
+    private DesignBindingPicker? _designBindingPicker;
+
+    public override bool IsDropDownResizable => true;
+
+    public override object? EditValue(ITypeDescriptorContext? context, IServiceProvider provider, object? value)
+    {
+        if (provider is null || context is null || context?.Instance is not { } instance)
+        {
+            return value;
+        }
+
+        if (TypeDescriptor.GetProperties(instance)[nameof(ComboBox.DataSource)] is not PropertyDescriptor property)
+        {
+            return value;
+        }
+
+        object? dataSource = property.GetValue(instance);
+
+        if (dataSource is null )
+        {
+            return value;
+        }
+
+        _designBindingPicker ??= new();
+
+        DesignBinding oldSelection = new DesignBinding(dataSource, (string?)value);
+        DesignBinding? newSelection = _designBindingPicker.Pick(
+            context,
+            provider,
+            showDataSources: false,
+            showDataMembers: true,
+            selectListMembers: false,
+            rootDataSource: dataSource,
+            rootDataMember: string.Empty,
+            initialSelectedItem: oldSelection
+        );
+
+        if (newSelection is null)
+        {
+            return value;
+        }
+
+        return newSelection.DataMember;
+    }
+
+    public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext? context) => UITypeEditorEditStyle.DropDown;
+}

src/System.Windows.Forms.Design/tests/UnitTests/DataMemberFieldEditorTests.cs

@@ -0,0 +1,51 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+#nullable enable
+
+using System.ComponentModel;
+using System.Drawing.Design;
+using Moq;
+
+namespace System.Windows.Forms.Design.Editors.Tests;
+
+public class DataMemberFieldEditorTests
+{
+    private readonly DataMemberFieldEditor _editor = new();
+
+    [Fact]
+    public void Ctor_HasDefaultProperties() => _editor.IsDropDownResizable.Should().BeTrue();
+
+    [Fact]
+    public void GetEditStyle_ContextIsNull_ReturnsDropDown() => _editor.GetEditStyle(null).Should().Be(UITypeEditorEditStyle.DropDown);
+
+    public static IEnumerable<object[]> EditValueCases()
+    {
+        string text = "Edited Text";
+
+        Mock<ITypeDescriptorContext>? contextMock = new();
+        contextMock.Setup(c => c.Instance).Returns(new ComboBox());
+
+        Mock<IServiceProvider> providerMock = new();
+        providerMock.Setup(p => p.GetService(typeof(IWindowsFormsEditorService))).Returns(new Mock<IWindowsFormsEditorService>().Object);
+
+        yield return new object[] { null!, null!, null! };
+        yield return new object[] { null!, null!, text };
+
+        yield return new object[]
+        {
+            contextMock.Object,
+            providerMock.Object,
+            text
+        };
+    }
+
+    [Theory]
+    [MemberData(nameof(EditValueCases))]
+    public void EditValue_WithValidInput_ReturnsValue(ITypeDescriptorContext? context, IServiceProvider provider, object? value)
+    {
+        object? result = _editor.EditValue(context, provider, value);
+
+        result.Should().Be(value);
+    }
+}

src/System.Windows.Forms/tests/IntegrationTests/WinformsControlsTest/ListBoxes.cs

@@ -11,6 +11,7 @@ public partial class ListBoxes : Form
     public ListBoxes()
     {
         InitializeComponent();
+        MinimumSize = new Size(Width, 900);
     }
 
     private void addButton_Click(object sender, EventArgs e)
@@ -60,4 +61,9 @@ private void ListBox_MeasureItem(object sender, MeasureItemEventArgs e)
             e.ItemHeight += 5;
         }
     }
+
+    private void Control_Click(object sender, EventArgs e)
+    {
+        propertyGrid.SelectedObject = sender;
+    }
 }

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/Design/DesignerAttributeTests.cs

@@ -26,7 +26,6 @@ public class DesignerAttributeTests
         $"System.Windows.Forms.Design.DataGridDesigner, {Assemblies.SystemDesign}",
         $"System.Windows.Forms.Design.DataGridViewColumnCollectionEditor, {Assemblies.SystemDesign}",
         $"System.Windows.Forms.Design.DataGridViewComponentEditor, {Assemblies.SystemDesign}",
-        $"System.Windows.Forms.Design.DataMemberFieldEditor, {Assemblies.SystemDesign}",
         $"System.Windows.Forms.Design.StatusBarDesigner, {Assemblies.SystemDesign}",
         $"System.Windows.Forms.Design.ToolBarButtonDesigner, {Assemblies.SystemDesign}",
         $"System.Windows.Forms.Design.ToolBarDesigner, {Assemblies.SystemDesign}",