Implementing UIA supporting for Form control

src/System.Windows.Forms/src/System/Windows/Forms/Form.AccessibleObject.cs

@@ -0,0 +1,55 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Drawing;
+
+namespace System.Windows.Forms
+{
+    public partial class Form
+    {
+        /// <summary>
+        ///  Form control accessible object with UI Automation provider functionality.
+        ///  This inherits from the base ControlAccessibleObject
+        ///  to have all base functionality.
+        /// </summary>
+        internal class FormAccessibleObject : ControlAccessibleObject
+        {
+            private readonly Form _owner;
+
+            internal FormAccessibleObject(Form owner) : base(owner)
+            {
+                _owner = owner;
+            }
+
+            public override Rectangle Bounds => _owner.RectangleToScreen(_owner.ClientRectangle);
+
+            internal override Rectangle BoundingRectangle => _owner.Bounds;
+
+            internal override bool IsIAccessibleExSupported()
+            {
+                if (_owner != null)
+                {
+                    return true;
+                }
+
+                return base.IsIAccessibleExSupported();
+            }
+
+            internal override bool IsPatternSupported(int patternId)
+            {
+                if (patternId == NativeMethods.UIA_LegacyIAccessiblePatternId)
+                {
+                    return true;
+                }
+
+                return base.IsPatternSupported(patternId);
+            }
+
+            internal override void SetValue(string newValue)
+            {
+                Value = newValue;
+            }
+        }
+    }
+}

src/System.Windows.Forms/src/System/Windows/Forms/Form.cs

@@ -31,7 +31,7 @@ namespace System.Windows.Forms
     DefaultEvent(nameof(Load)),
     InitializationEvent(nameof(Load)),
     ]
-    public class Form : ContainerControl
+    public partial class Form : ContainerControl
     {
 #if DEBUG
         static readonly BooleanSwitch AlwaysRestrictWindows = new BooleanSwitch("AlwaysRestrictWindows", "Always make Form classes behave as though they are restricted");
@@ -1707,10 +1707,10 @@ public Form[] MdiChildren
         }
 
         /// <summary>
-            ///  Gets the MDIClient that the MDI container form is using to contain Multiple Document Interface (MDI) child forms,
+        ///  Gets the MDIClient that the MDI container form is using to contain Multiple Document Interface (MDI) child forms,
         ///  if this is an MDI container form.
         ///  Represents the client area of a Multiple Document Interface (MDI) Form window, also known as the MDI child window.
-            /// </summary>
+        /// </summary>
         internal MdiClient MdiClient
         {
             get
@@ -3361,6 +3361,11 @@ private Size ComputeWindowSize(Size clientSize, int style, int exStyle)
             return new Size(result.right - result.left, result.bottom - result.top);
         }
 
+        protected override AccessibleObject CreateAccessibilityInstance()
+        {
+            return new FormAccessibleObject(this);
+        }
+
         [EditorBrowsable(EditorBrowsableState.Advanced)]
         protected override Control.ControlCollection CreateControlsInstance()
         {
@@ -3552,7 +3557,7 @@ private void DeactivateMdiChild()
         ///  a
         ///  subclass overrides this function,
         ///  it must call the base implementation.
-            /// </summary>
+        /// </summary>
         [
             EditorBrowsable(EditorBrowsableState.Advanced)
         ]
@@ -4252,7 +4257,7 @@ private protected override void OnAutoScaleModeChanged()
             base.OnAutoScaleModeChanged();
             if (formStateEx[FormStateExSettingAutoScale] != 1)
             {
-            // Obsolete code required here for backwards compat
+                // Obsolete code required here for backwards compat
 #pragma warning disable 618
                 AutoScale = false;
 #pragma warning restore 618
@@ -5873,6 +5878,8 @@ internal bool ShouldSerializeTransparencyKey()
             return !TransparencyKey.Equals(Color.Empty);
         }
 
+        internal override bool SupportsUiaProviders => true;
+
         /// <summary>
         ///  This is called when we are about to become minimized.  Laying out
         ///  while minimized can be a problem because the physical dimensions
@@ -6202,7 +6209,7 @@ internal void UpdateFormStyles()
         private static Type FindClosestStockType(Type type)
         {
             Type[] stockTypes = new Type[] { typeof(MenuStrip) }; // as opposed to what we had before...
-            // simply add other types here from most specific to most generic if we want to merge other types of toolstrips...
+                                                                  // simply add other types here from most specific to most generic if we want to merge other types of toolstrips...
             foreach (Type t in stockTypes)
             {
                 if (t.IsAssignableFrom(type))
@@ -7343,7 +7350,7 @@ public override void Add(Control value)
             }
 
             /// <summary>
-                ///  Removes a control from the form.
+            ///  Removes a control from the form.
             /// </summary>
             public override void Remove(Control value)
             {