[WinForms] Make `ContextMenuStrip` behavior closer to the reference one (#18598)

* [WinForms] Make `ContextMenuStrip` behavior closer to the reference one

* Bump API snapshot submodule

Co-authored-by: monojenkins <jo.shields+jenkins@xamarin.com>

6 files changed, 217 insertions, 56 deletions

diff --git a/mcs/class/System.Windows.Forms/System.Windows.Forms/ContextMenuStrip.cs b/mcs/class/System.Windows.Forms/System.Windows.Forms/ContextMenuStrip.cs
index 1df14883d09..c95804739f9 100644
--- a/mcs/class/System.Windows.Forms/System.Windows.Forms/ContextMenuStrip.cs
+++ b/mcs/class/System.Windows.Forms/System.Windows.Forms/ContextMenuStrip.cs
@@ -35,27 +35,23 @@ namespace System.Windows.Forms
 	[DefaultEvent ("Opening")]
 	public class ContextMenuStrip : ToolStripDropDownMenu
 	{
-		Control source_control;
-		internal Control container;
+		internal Control AssociatedControl;
 
 		#region Public Construtors
 		public ContextMenuStrip () : base ()
 		{
-			source_control = null;
 		}
 		
-		public ContextMenuStrip (IContainer container) : base ()
+		public ContextMenuStrip (IContainer container) : this ()
 		{
-			source_control = null;
+			// TODO: handle `container` argument
 		}
 		#endregion
 
 		#region Public Properties
 		[Browsable (false)]
 		[DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
-		public Control SourceControl {
-			get { return this.source_control; }
-		}
+		public Control SourceControl { get; protected set; }
 		#endregion
 
 		#region Protected Methods
@@ -70,11 +66,12 @@ namespace System.Windows.Forms
 			if (visible)
 				XplatUI.SetTopmost (this.Handle, true);
 		}
-		#endregion
 
-		internal void SetSourceControl (Control source_control)
+		protected override void SetOwnerControl (Control control)
 		{
-			container = this.source_control = source_control;
+			base.SetOwnerControl (control);
+			SourceControl = control;
 		}
+		#endregion
 	}
 }
diff --git a/mcs/class/System.Windows.Forms/System.Windows.Forms/Control.cs b/mcs/class/System.Windows.Forms/System.Windows.Forms/Control.cs
index ecd8c90e51b..d85c52dff6e 100644
--- a/mcs/class/System.Windows.Forms/System.Windows.Forms/Control.cs
+++ b/mcs/class/System.Windows.Forms/System.Windows.Forms/Control.cs
@@ -2426,7 +2426,7 @@ namespace System.Windows.Forms
 				if (this.context_menu_strip != value) {
 					this.context_menu_strip = value;
 					if (value != null)
-						value.container = this;
+						value.AssociatedControl = this;
 					OnContextMenuStripChanged (EventArgs.Empty);
 				}
 			}
@@ -5497,22 +5497,21 @@ namespace System.Windows.Forms
 				return;
 			}
 
-				// If there isn't a regular context menu, show the Strip version
-				if (context_menu == null && context_menu_strip != null) {
-					Point pt;
+			// If there isn't a regular context menu, show the Strip version
+			if (context_menu == null && context_menu_strip != null) {
+				Point pt;
 
-					pt = new Point (LowOrder ((int)m.LParam.ToInt32 ()), HighOrder ((int)m.LParam.ToInt32 ()));
-					
-					if (pt.X == -1 || pt.Y == -1) { 
-						pt.X = (this.Width / 2) + this.Left; 
-						pt.Y = (this.Height /2) + this.Top; 
-						pt = this.PointToScreen (pt);
-					}
-					
-					context_menu_strip.SetSourceControl (this);
-					context_menu_strip.Show (this, PointToClient (pt));
-					return;
+				pt = new Point (LowOrder ((int)m.LParam.ToInt32 ()), HighOrder ((int)m.LParam.ToInt32 ()));
+				
+				if (pt.X == -1 || pt.Y == -1) { 
+					pt.X = (this.Width / 2) + this.Left; 
+					pt.Y = (this.Height /2) + this.Top; 
+					pt = this.PointToScreen (pt);
 				}
+				
+				context_menu_strip.Show (this, PointToClient (pt));
+				return;
+			}
 			DefWndProc(ref m);
 		}
 
@@ -6499,7 +6498,6 @@ namespace System.Windows.Forms
 			remove { Events.RemoveHandler (ContextMenuStripChangedEvent, value);}
 		}
 
-
 		[EditorBrowsable(EditorBrowsableState.Advanced)]
 		[Browsable(true)]
 		public event ControlEventHandler ControlAdded {
diff --git a/mcs/class/System.Windows.Forms/System.Windows.Forms/ToolStripDropDown.cs b/mcs/class/System.Windows.Forms/System.Windows.Forms/ToolStripDropDown.cs
index 33eb3c50b99..2bf32495378 100644
--- a/mcs/class/System.Windows.Forms/System.Windows.Forms/ToolStripDropDown.cs
+++ b/mcs/class/System.Windows.Forms/System.Windows.Forms/ToolStripDropDown.cs
@@ -383,26 +383,36 @@ namespace System.Windows.Forms
 		[EditorBrowsable (EditorBrowsableState.Never)]
 		public new void Show ()
 		{
-			Show (Location, DefaultDropDownDirection);
+			Show (Location);
+		}
+
+		public void Show (int x, int y)
+		{
+			Show (new Point (x, y));
 		}
 		
 		public void Show (Point screenLocation)
 		{
+			SetOwnerControl (null);
 			Show (screenLocation, DefaultDropDownDirection);
 		}
-		
+
+		public void Show (Control control, int x, int y)
+		{
+			Show (control, new Point (x, y));
+		}
+
 		public void Show (Control control, Point position)
 		{
-			if (control == null)
-				throw new ArgumentNullException ("control");
-			
-			XplatUI.SetOwner (Handle, control.Handle);
-			Show (control.PointToScreen (position), DefaultDropDownDirection);
+			Show (control, position, DefaultDropDownDirection);
 		}
 		
-		public void Show (int x, int y)
+		public void Show (Control control, Point position, ToolStripDropDownDirection direction)
 		{
-			Show (new Point (x, y), DefaultDropDownDirection);
+			if (control == null)
+				throw new ArgumentNullException ("control");
+			SetOwnerControl (control);
+			Show (control.PointToScreen (position), direction);
 		}
 		
 		public void Show (Point position, ToolStripDropDownDirection direction)
@@ -522,26 +532,17 @@ namespace System.Windows.Forms
 
 			this.OnOpened (EventArgs.Empty);
 		}
-		
-		public void Show (Control control, int x, int y)
-		{
-			if (control == null)
-				throw new ArgumentNullException ("control");
 
-			Show (control, new Point (x, y));
-		}
-		
-		public void Show (Control control, Point position, ToolStripDropDownDirection direction)
-		{
-			if (control == null)
-				throw new ArgumentNullException ("control");
-
-			XplatUI.SetOwner (Handle, control.Handle);
-			Show (control.PointToScreen (position), direction);
-		}
 		#endregion
 
 		#region Protected Methods
+
+		protected virtual void SetOwnerControl (Control ownerControl)
+		{
+			var ownerControlHandle = (ownerControl == null) ? IntPtr.Zero : ownerControl.Handle;
+			XplatUI.SetOwner (Handle, ownerControlHandle);
+		}
+
 		protected override AccessibleObject CreateAccessibilityInstance ()
 		{
 			return new ToolStripDropDownAccessibleObject (this);
diff --git a/mcs/class/System.Windows.Forms/System.Windows.Forms/ToolStripMenuItem.cs b/mcs/class/System.Windows.Forms/System.Windows.Forms/ToolStripMenuItem.cs
index 4df33979088..7a60ac82f29 100644
--- a/mcs/class/System.Windows.Forms/System.Windows.Forms/ToolStripMenuItem.cs
+++ b/mcs/class/System.Windows.Forms/System.Windows.Forms/ToolStripMenuItem.cs
@@ -419,10 +419,8 @@ namespace System.Windows.Forms
 			if (item.Owner == null)
 				return null;
 
-			if (item.Owner is ContextMenuStrip) {
-				Control container = ((ContextMenuStrip)item.Owner).container;
-				return container == null ? null : container.TopLevelControl;
-			}
+			if (item.Owner is ContextMenuStrip ownerContextMenuStrip) 
+				return ownerContextMenuStrip.SourceControl?.TopLevelControl;
 
 			// MainMenuStrip
 			return item.Owner.TopLevelControl;
diff --git a/mcs/class/System.Windows.Forms/System.Windows.Forms_test.dll.sources b/mcs/class/System.Windows.Forms/System.Windows.Forms_test.dll.sources
index a4045f284ea..c9eb6898556 100644
--- a/mcs/class/System.Windows.Forms/System.Windows.Forms_test.dll.sources
+++ b/mcs/class/System.Windows.Forms/System.Windows.Forms_test.dll.sources
@@ -26,6 +26,7 @@ System.Windows.Forms/Common.cs
 System.Windows.Forms/CommonDialogsTest.cs
 System.Windows.Forms/ContainerControlTest.cs
 System.Windows.Forms/ContextMenuTest.cs
+System.Windows.Forms/ContextMenuStripTest.cs
 System.Windows.Forms/ControlBindingsCollectionTest.cs
 System.Windows.Forms/ControlBindingsConverterTest.cs
 System.Windows.Forms/ControlCollectionTest.cs
diff --git a/mcs/class/System.Windows.Forms/Test/System.Windows.Forms/ContextMenuStripTest.cs b/mcs/class/System.Windows.Forms/Test/System.Windows.Forms/ContextMenuStripTest.cs
new file mode 100644
index 00000000000..f5f62d6d330
--- /dev/null
+++ b/mcs/class/System.Windows.Forms/Test/System.Windows.Forms/ContextMenuStripTest.cs
@@ -0,0 +1,166 @@
+//
+// ContextMenuTestStrip.cs: Test cases for ContextMenuStrip
+//
+// Author:
+//   Nikita Voronchev (nikita.voronchev@ru.axxonsoft.com)
+//
+// (C) 2020 AxxonSoft (https://www.axxonsoft.com/)
+//
+
+using System;
+using System.Drawing;
+using System.Windows.Forms;
+using NUnit.Framework;
+
+namespace MonoTests.System.Windows.Forms
+{
+	// TODO:
+	//  -- Tests around `OwnerItem`.
+
+	[TestFixture]
+	public class ContextMenuStripTest : TestHelper
+	{
+		static TestExtendedForm form;
+		static Label explicitMenuSrcLabel;
+		static TestExtendedLabel testExtendedLabel;
+		static ContextMenuStrip contextMenuStrip;
+
+		static readonly Lazy<Control>[] testCaseExplicitMenuSources = new Lazy<Control>[] {
+			new Lazy<Control>(() => null),
+			new Lazy<Control>(() => explicitMenuSrcLabel)
+		};  // Involve `Lazy` to use `TestCaseSource` attribute.
+
+		static readonly Lazy<ITestExtendedControl>[] testCaseAssociatedControls = new Lazy<ITestExtendedControl>[] {
+			new Lazy<ITestExtendedControl>(() => form),
+			new Lazy<ITestExtendedControl>(() => testExtendedLabel)
+		};  // Involve `Lazy` to use `TestCaseSource` attribute.
+
+		[SetUp]
+		public void SetUp()
+		{
+			form = new TestExtendedForm ();
+			explicitMenuSrcLabel = new Label ();
+			testExtendedLabel = new TestExtendedLabel ();
+			contextMenuStrip = new ContextMenuStrip ();
+			
+			form.ShowInTaskbar = false;
+			form.Controls.Add (explicitMenuSrcLabel);
+			form.Controls.Add (testExtendedLabel);
+		}
+
+		[TearDown]
+		public void TearDown()
+		{
+			contextMenuStrip.Close ();
+			form.Controls.Clear ();
+
+			contextMenuStrip.Dispose ();
+			testExtendedLabel.Dispose ();
+			explicitMenuSrcLabel.Dispose ();
+			form.Dispose ();
+		}
+
+		[Test, TestCaseSource ("testCaseExplicitMenuSources")]
+		public void DirectShowTest01 (Lazy<Control> explicitMenuSrc)
+		{
+			AssingOwner (explicitMenuSrc.Value);
+			contextMenuStrip.Show ();
+			Assert.IsNull (contextMenuStrip.SourceControl, "SourceControl");
+		}
+
+		[Test, TestCaseSource ("testCaseExplicitMenuSources")]
+		public void DirectShowTest02 (Lazy<Control> explicitMenuSrc)
+		{
+			AssingOwner (explicitMenuSrc.Value);
+			contextMenuStrip.Show (form, Point.Empty);
+			Assert.AreEqual (form, contextMenuStrip.SourceControl, "SourceControl");
+		}
+
+		[Test, TestCaseSource ("testCaseExplicitMenuSources")]
+		public void DirectShowTest03 (Lazy<Control> explicitMenuSrc)
+		{
+			AssingOwner (explicitMenuSrc.Value);
+			contextMenuStrip.Show (explicitMenuSrcLabel, Point.Empty);
+			Assert.AreEqual (explicitMenuSrcLabel, contextMenuStrip.SourceControl, "SourceControl");
+		}
+
+		[Test, TestCaseSource ("testCaseExplicitMenuSources")]
+		public void DirectShowTest04 (Lazy<Control> explicitMenuSrc)
+		{
+			AssingOwner (explicitMenuSrc.Value);
+			contextMenuStrip.Show (testExtendedLabel, Point.Empty);
+			Assert.AreEqual (testExtendedLabel, contextMenuStrip.SourceControl, "SourceControl");
+		}
+
+		[Test, TestCaseSource ("testCaseExplicitMenuSources")]
+		public void DirectShowTest05 (Lazy<Control> explicitMenuSrc)
+		{
+			AssingOwner (explicitMenuSrc.Value);
+			contextMenuStrip.Show (form, Point.Empty);
+			contextMenuStrip.Close ();
+			contextMenuStrip.Show ();
+			Assert.IsNull (contextMenuStrip.SourceControl, "SourceControl");
+		}
+
+		[Test, TestCaseSource("testCaseAssociatedControls")]
+		public void ContextShowTest (Lazy<ITestExtendedControl> associatedControl)
+		{
+			bool menuHasBeenOpened = false;
+			contextMenuStrip.Opened += (sender, args) => { menuHasBeenOpened = true; };
+			
+			var assCtrl = associatedControl.Value;
+			assCtrl.ContextMenuStrip = contextMenuStrip;
+			
+			Assert.IsFalse (menuHasBeenOpened, "menuHasBeenOpened");
+			assCtrl.EmulateWmContextMenu ();
+			Assert.IsTrue (menuHasBeenOpened, "menuHasBeenOpened");
+			Assert.AreEqual (assCtrl, contextMenuStrip.SourceControl, "SourceControl");
+
+		}
+
+		#region Helpers
+
+		private void AssingOwner (Control explicitMenuSrc)
+		{
+			if (explicitMenuSrc != null)
+				explicitMenuSrc.ContextMenuStrip = contextMenuStrip;
+		}
+
+		public interface ITestExtendedControl
+		{
+			void EmulateWmContextMenu ();
+			ContextMenuStrip ContextMenuStrip { set; }
+		}
+
+		class TestExtendedForm : Form, ITestExtendedControl
+		{
+			public void EmulateWmContextMenu ()
+			{
+				var m = TestExtendedControlHelper.MakeWmContextMenu ();
+				WndProc (ref m);
+			}
+		}
+
+		class TestExtendedLabel : Label, ITestExtendedControl
+		{
+			public void EmulateWmContextMenu ()
+			{
+				var m = TestExtendedControlHelper.MakeWmContextMenu ();
+				WndProc (ref m);
+			}
+		}
+
+		static class TestExtendedControlHelper
+		{
+			public static Message MakeWmContextMenu ()
+			{
+				return new Message () {
+					Msg = (int)Msg.WM_CONTEXTMENU,
+					LParam = IntPtr.Zero
+				};
+			}
+		}
+
+		#endregion  // end of Helpers
+	}
+}