Issus 4908 port save file dialog designer and folder browser dialog designer

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

@@ -49,10 +49,12 @@
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.PrintDialogDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.RadioButtonDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.RichTextBoxDesigner))]
+[assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.SaveFileDialogDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.SplitContainerDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.SplitterPanelDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.SplitterDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.FlowLayoutPanelDesigner))]
+[assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.FolderBrowserDialogDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.TabControlDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.TableLayoutPanelDesigner))]
 [assembly: TypeForwardedTo(typeof(System.Windows.Forms.Design.TabPageDesigner))]

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

@@ -1,3 +1,4 @@
+virtual System.ComponentModel.Design.ComponentDesigner.SetTextualDefaultProperty.get -> bool
 *REMOVED*System.ComponentModel.Design.DesignerActionListCollection.AddRange(System.ComponentModel.Design.DesignerActionList?[]! value) -> void
 *REMOVED*~System.Windows.Forms.Design.Behavior.BehaviorServiceAdornerCollection.AddRange(System.Windows.Forms.Design.Behavior.Adorner[] value) -> void
 *REMOVED*~System.Windows.Forms.Design.Behavior.GlyphCollection.AddRange(System.Windows.Forms.Design.Behavior.Glyph[] value) -> void

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

@@ -34,6 +34,24 @@ public partial class ComponentDesigner : ITreeDesigner, IDesignerFilter, ICompon
     /// </summary>
     public virtual ICollection AssociatedComponents => Array.Empty<IComponent>();
 
+    private protected virtual void UpdateTextualDefaultProperty()
+    {
+        var component = Component;
+        if (component?.Site is { } site)
+        {
+            PropertyDescriptor defaultProperty = TypeDescriptor.GetDefaultProperty(component);
+            if (!(defaultProperty is not null && defaultProperty.PropertyType.Equals(typeof(string))))
+            {
+                return;
+            }
+
+            if (defaultProperty.GetValue(component) is string currentValue && string.IsNullOrEmpty(currentValue))
+            {
+                defaultProperty.SetValue(component, site.Name);
+            }
+        }
+    }
+
     internal virtual bool CanBeAssociatedWith(IDesigner parentDesigner) => true;
 
     /// <summary>
@@ -125,6 +143,15 @@ public virtual void InitializeNewComponent(IDictionary defaultValues)
     {
         // execute legacy code
         InitializeNonDefault();
+
+        // Note: This was originally an obsoleted API called OnSetComponentDefaults(). The
+        // default behavior of this API was to set the the default property to the component's
+        // site name, if the property was a string and null or empty. We've removed the API
+        // but preserved the same behavior, now controlled by SetTextualDefaultProperty.
+        if (SetTextualDefaultProperty)
+        {
+            UpdateTextualDefaultProperty();
+        }
     }
 
     void IDesignerFilter.PostFilterAttributes(IDictionary attributes) => PostFilterAttributes(attributes);
@@ -149,6 +176,12 @@ public virtual void InitializeNewComponent(IDictionary defaultValues)
     /// </summary>
     public virtual DesignerVerbCollection Verbs => _verbs ??= new DesignerVerbCollection();
 
+    /// <summary>
+    ///  Controls whether the default property of <see cref="Component"/> is automatically set
+    ///  to <see cref="ISite.Name"/> on creation. The default is <see langword="true"/>.
+    /// </summary>
+    protected virtual bool SetTextualDefaultProperty => true;
+
     ICollection ITreeDesigner.Children
     {
         get

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

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.ComponentModel.Design;
+
+namespace System.Windows.Forms.Design;
+
+internal class FolderBrowserDialogDesigner : ComponentDesigner
+{
+    // Overridden to avoid setting the default property ("SelectedPath")
+    // to the Site.Name (i.e. folderBrowserDialog1).
+    protected override bool SetTextualDefaultProperty => false;
+}

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/FolderNameEditor.FolderBrowser.cs

@@ -94,7 +94,7 @@ public unsafe DialogResult ShowDialog(IWin32Window? owner)
                     }
 
                     // Retrieve the path from the IDList.
-                    PWSTR selectedPath = default;
+                    PWSTR selectedPath = pDisplayName;
                     PInvoke.SHGetPathFromIDList(browseHandle, selectedPath);
                     DirectoryPath = new string((char*)selectedPath);
                     return DialogResult.OK;

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

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.ComponentModel.Design;
+
+namespace System.Windows.Forms.Design;
+
+internal class SaveFileDialogDesigner : ComponentDesigner
+{
+    // Overridden to avoid setting the default property ("FileName")
+    // to the Site.Name (i.e. saveFileDialog1).
+    protected override bool SetTextualDefaultProperty => false;
+}