Improve DropDownButton Rendering in PropertyGrid.

Author: KlausLoeffelmann

src/System.Windows.Forms/System/Windows/Forms/Controls/PropertyGrid/PropertyGridInternal/DropDownButton.cs

@@ -4,6 +4,7 @@
 using System.Drawing;
 using System.Windows.Forms.ButtonInternal;
 using System.Windows.Forms.VisualStyles;
+using static System.Windows.Forms.ControlPaint;
 
 namespace System.Windows.Forms.PropertyGridInternal;
 
@@ -17,6 +18,12 @@ public DropDownButton()
         SetAccessibleName();
     }
 
+    // If a control uses it needs it in the context of rendering
+    // something in dark mode - this flag needs to be set.
+    public bool RequestDarkModeRendering { get; set; }
+
+    public ModernControlButtonStyle ControlButtonStyle { get; set; }
+
     // When the holder is open, we don't fire clicks.
     public bool IgnoreMouse { get; set; }
 
@@ -64,52 +71,82 @@ protected override void OnMouseDown(MouseEventArgs e)
         }
     }
 
+#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
     protected override void OnPaint(PaintEventArgs pevent)
     {
-        base.OnPaint(pevent);
+        ComboBoxState state = ComboBoxState.Normal;
 
-#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
-        if (!Application.IsDarkModeEnabled
-            && (Application.RenderWithVisualStyles & _useComboBoxTheme))
+        if (MouseIsDown)
         {
-            ComboBoxState state = ComboBoxState.Normal;
-
-            if (MouseIsDown)
-            {
-                state = ComboBoxState.Pressed;
-            }
-            else if (MouseIsOver)
-            {
-                state = ComboBoxState.Hot;
-            }
+            state = ComboBoxState.Pressed;
+        }
+        else if (MouseIsOver)
+        {
+            state = ComboBoxState.Hot;
+        }
 
-            Rectangle dropDownButtonRect = new(0, 0, Width, Height);
-            if (state == ComboBoxState.Normal)
-            {
-                pevent.Graphics.FillRectangle(SystemBrushes.Window, dropDownButtonRect);
-            }
+        base.OnPaint(pevent);
 
-            using (DeviceContextHdcScope hdc = new(pevent))
+        if (Application.IsDarkModeEnabled && RequestDarkModeRendering)
+        {
+            ModernControlButtonState buttonState = state switch
             {
-                ComboBoxRenderer.DrawDropDownButtonForHandle(
-                    hdc,
-                    dropDownButtonRect,
-                    state,
-                    ScaleHelper.IsScalingRequirementMet ? HWNDInternal : HWND.Null);
-            }
+                ComboBoxState.Disabled => ModernControlButtonState.Disabled,
+                ComboBoxState.Hot => ModernControlButtonState.Hover,
+                ComboBoxState.Pressed => ModernControlButtonState.Pressed,
+                _ => ModernControlButtonState.Normal
+            };
+
+            DrawModernControlButton(
+                pevent.Graphics,
+                new Rectangle(0, 0, Width, Height),
+                ControlButtonStyle,
+                buttonState,
+                isDarkMode: true);
+
+            return;
+        }
 
-            // Redraw focus cues.
-            //
-            // For consistency with other PropertyGrid buttons, i.e. those opening system dialogs ("..."), that
-            // always show visual cues when focused, we need to do the same for this custom button, painted as
-            // a ComboBox control part (drop-down).
-            if (Focused)
-            {
-                dropDownButtonRect.Inflate(-1, -1);
-                ControlPaint.DrawFocusRectangle(pevent.Graphics, dropDownButtonRect, ForeColor, BackColor);
-            }
+        if (Application.RenderWithVisualStyles & _useComboBoxTheme)
+        {
+            RenderComboBoxButtonWithVisualStyles(pevent, state);
         }
+    }
 #pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+    private void RenderComboBoxButtonWithVisualStyles(PaintEventArgs pevent, ComboBoxState state)
+    {
+        Rectangle dropDownButtonRect = new(0, 0, Width, Height);
+
+        if (state == ComboBoxState.Normal)
+        {
+            pevent.Graphics.FillRectangle(
+                SystemBrushes.Window,
+                dropDownButtonRect);
+        }
+
+        using (DeviceContextHdcScope hdc = new(pevent))
+        {
+            ComboBoxRenderer.DrawDropDownButtonForHandle(
+                hdc,
+                dropDownButtonRect,
+                state,
+                ScaleHelper.IsScalingRequirementMet ? HWNDInternal : HWND.Null);
+        }
+
+        // Redraw focus cues.
+        //
+        // For consistency with other PropertyGrid buttons, i.e. those opening system dialogs ("..."), that
+        // always show visual cues when focused, we need to do the same for this custom button, painted as
+        // a ComboBox control part (drop-down).
+        if (Focused)
+        {
+            dropDownButtonRect.Inflate(-1, -1);
+            DrawFocusRectangle(
+                pevent.Graphics,
+                dropDownButtonRect,
+                ForeColor,
+                BackColor);
+        }
     }
 
     internal void PerformButtonClick()

src/System.Windows.Forms/System/Windows/Forms/Controls/PropertyGrid/PropertyGridInternal/PropertyGridView.cs

@@ -11,6 +11,7 @@
 using Microsoft.Win32;
 using Windows.Win32.System.Variant;
 using Windows.Win32.UI.Accessibility;
+using static System.Windows.Forms.ControlPaint;
 
 namespace System.Windows.Forms.PropertyGridInternal;
 
@@ -190,33 +191,44 @@ public bool CanUndo
     ///   the selected row's <see cref="GridEntry"/>.
     ///  </para>
     /// </remarks>
+#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
     internal DropDownButton DropDownButton
     {
         get
         {
-            if (_dropDownButton is null)
+            if (_dropDownButton is not null)
             {
-                OwnerGrid.CheckInCreate();
+                return _dropDownButton;
+            }
 
-                _dropDownButton = new()
-                {
-                    UseComboBoxTheme = true
-                };
+            OwnerGrid.CheckInCreate();
 
-                Bitmap bitmap = CreateResizedBitmap("Arrow", DownArrowIconWidth, DownArrowIconHeight);
-                _dropDownButton.Image = bitmap;
-                _dropDownButton.BackColor = SystemColors.Control;
-                _dropDownButton.ForeColor = SystemColors.ControlText;
-                _dropDownButton.Click += OnButtonClick;
-                _dropDownButton.GotFocus += OnDropDownButtonGotFocus;
-                _dropDownButton.LostFocus += OnChildLostFocus;
-                _dropDownButton.TabIndex = 2;
+            _dropDownButton = new()
+            {
+                UseComboBoxTheme = true,
+                RequestDarkModeRendering = Application.IsDarkModeEnabled,
+                ControlButtonStyle = ModernControlButtonStyle.OpenDropDown | ModernControlButtonStyle.RoundedBorder
+            };
 
-                CommonEditorSetup(_dropDownButton);
-                _dropDownButton.Size = ScaleHelper.IsScalingRequirementMet
-                    ? new(SystemInformation.VerticalScrollBarArrowHeightForDpi(DeviceDpiInternal), RowHeight)
-                    : new(SystemInformation.VerticalScrollBarArrowHeight, RowHeight);
-            }
+            Bitmap bitmap = CreateResizedBitmap(
+                "Arrow",
+                DownArrowIconWidth,
+                DownArrowIconHeight);
+
+            // For classic mode/backwards compatibility.
+            _dropDownButton.Image = bitmap;
+            _dropDownButton.BackColor = SystemColors.Control;
+            _dropDownButton.ForeColor = SystemColors.ControlText;
+            _dropDownButton.Click += OnButtonClick;
+            _dropDownButton.GotFocus += OnDropDownButtonGotFocus;
+            _dropDownButton.LostFocus += OnChildLostFocus;
+            _dropDownButton.TabIndex = 2;
+
+            CommonEditorSetup(_dropDownButton);
+
+            _dropDownButton.Size = ScaleHelper.IsScalingRequirementMet
+                ? new(SystemInformation.VerticalScrollBarArrowHeightForDpi(DeviceDpiInternal), RowHeight)
+                : new(SystemInformation.VerticalScrollBarArrowHeight, RowHeight);
 
             return _dropDownButton;
         }
@@ -235,32 +247,42 @@ internal Button DialogButton
     {
         get
         {
-            if (_dialogButton is null)
+            if (_dialogButton is not null)
             {
-                OwnerGrid.CheckInCreate();
+                return _dialogButton;
+            }
 
-                _dialogButton = new DropDownButton
-                {
-                    BackColor = SystemColors.Control,
-                    ForeColor = SystemColors.ControlText,
-                    TabIndex = 3,
-                    Image = CreateResizedBitmap("dotdotdot", DotDotDotIconWidth, DotDotDotIconHeight)
-                };
+            OwnerGrid.CheckInCreate();
 
-                _dialogButton.Click += OnButtonClick;
-                _dialogButton.KeyDown += OnButtonKeyDown;
-                _dialogButton.GotFocus += OnDropDownButtonGotFocus;
-                _dialogButton.LostFocus += OnChildLostFocus;
-                _dialogButton.Size = ScaleHelper.IsScalingRequirementMet
-                    ? new Size(SystemInformation.VerticalScrollBarArrowHeightForDpi(DeviceDpiInternal), RowHeight)
-                    : new Size(SystemInformation.VerticalScrollBarArrowHeight, RowHeight);
+            _dialogButton = new DropDownButton
+            {
+                RequestDarkModeRendering = Application.IsDarkModeEnabled,
+                ControlButtonStyle = ModernControlButtonStyle.Ellipse | ModernControlButtonStyle.RoundedBorder,
+                BackColor = SystemColors.Control,
+                ForeColor = SystemColors.ControlText,
+                TabIndex = 3,
 
-                CommonEditorSetup(_dialogButton);
-            }
+                // For classic mode/backwards compatibility.
+                Image = CreateResizedBitmap(
+                    "dotdotdot",
+                    DotDotDotIconWidth,
+                    DotDotDotIconHeight)
+            };
+
+            _dialogButton.Click += OnButtonClick;
+            _dialogButton.KeyDown += OnButtonKeyDown;
+            _dialogButton.GotFocus += OnDropDownButtonGotFocus;
+            _dialogButton.LostFocus += OnChildLostFocus;
+            _dialogButton.Size = ScaleHelper.IsScalingRequirementMet
+                ? new Size(SystemInformation.VerticalScrollBarArrowHeightForDpi(DeviceDpiInternal), RowHeight)
+                : new Size(SystemInformation.VerticalScrollBarArrowHeight, RowHeight);
+
+            CommonEditorSetup(_dialogButton);
 
             return _dialogButton;
         }
     }
+#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 
     /// <summary>
     ///  The common text box for editing values.
@@ -269,30 +291,32 @@ private GridViewTextBox EditTextBox
     {
         get
         {
-            if (_editTextBox is null)
+            if (_editTextBox is not null)
             {
-                OwnerGrid.CheckInCreate();
+                return _editTextBox;
+            }
 
-                _editTextBox = new(this)
-                {
-                    BorderStyle = BorderStyle.None,
-                    AutoSize = false,
-                    TabStop = false,
-                    AcceptsReturn = true,
-                    BackColor = BackColor,
-                    ForeColor = ForeColor
-                };
+            OwnerGrid.CheckInCreate();
 
-                _editTextBox.KeyDown += OnEditKeyDown;
-                _editTextBox.KeyPress += OnEditKeyPress;
-                _editTextBox.GotFocus += OnEditGotFocus;
-                _editTextBox.LostFocus += OnEditLostFocus;
-                _editTextBox.MouseDown += OnEditMouseDown;
-                _editTextBox.TextChanged += OnEditChange;
+            _editTextBox = new(this)
+            {
+                BorderStyle = BorderStyle.None,
+                AutoSize = false,
+                TabStop = false,
+                AcceptsReturn = true,
+                BackColor = BackColor,
+                ForeColor = ForeColor
+            };
 
-                _editTextBox.TabIndex = 1;
-                CommonEditorSetup(_editTextBox);
-            }
+            _editTextBox.KeyDown += OnEditKeyDown;
+            _editTextBox.KeyPress += OnEditKeyPress;
+            _editTextBox.GotFocus += OnEditGotFocus;
+            _editTextBox.LostFocus += OnEditLostFocus;
+            _editTextBox.MouseDown += OnEditMouseDown;
+            _editTextBox.TextChanged += OnEditChange;
+
+            _editTextBox.TabIndex = 1;
+            CommonEditorSetup(_editTextBox);
 
             return _editTextBox;
         }
@@ -2210,7 +2234,7 @@ protected override void OnGotFocus(EventArgs e)
             if ((Size.Width > doubleOffset) && (Size.Height > doubleOffset))
             {
                 using Graphics g = CreateGraphicsInternal();
-                ControlPaint.DrawFocusRectangle(g, new Rectangle(_offset2Units, _offset2Units, Size.Width - doubleOffset, Size.Height - doubleOffset));
+                DrawFocusRectangle(g, new Rectangle(_offset2Units, _offset2Units, Size.Width - doubleOffset, Size.Height - doubleOffset));
             }
         }
     }

src/System.Windows.Forms/System/Windows/Forms/Rendering/ControlPaint.ModernControlButton.cs

@@ -6,17 +6,18 @@ namespace System.Windows.Forms;
 public static unsafe partial class ControlPaint
 {
     [Flags]
-    internal enum ModernControlButton
+    internal enum ModernControlButtonStyle
     {
         Empty = 0x0,
         Up = 0x1,
         Down = 0x2,
         UpDown = 0x3,
         Right = 0x4,
         Left = 0x8,
-        LeftRight = 0xC,
+        RightLeft = 0xC,
         Ellipse = 0x10,
+        OpenDropDown = 0x20,
         SingleBorder = 0x10000,
-        RoundedBorder = 0x20000
+        RoundedBorder = 0x20000,
     }
 }

src/System.Windows.Forms/System/Windows/Forms/Rendering/ControlPaint.ModernControlButtonState.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Windows.Forms;
+
+public static unsafe partial class ControlPaint
+{
+    internal enum ModernControlButtonState
+    {
+        Normal,
+        Disabled,
+        Pressed,
+        Hover
+    }
+}