From 5483071599cb0a3802c15389b8e893210b5f03b9 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sat, 12 Jun 2021 15:42:39 -0400
Subject: [PATCH] Fix cancellable contexts #6057

---
 .../Pages/ContextFlyoutPage.xaml              |  5 +--
 .../ControlCatalog/Pages/ContextMenuPage.xaml |  7 ++--
 src/Avalonia.Controls/ContextMenu.cs          |  6 ++++
 src/Avalonia.Controls/Flyouts/FlyoutBase.cs   | 33 +++++++++++++++----
 src/Avalonia.Controls/Primitives/Popup.cs     | 10 ++++++
 5 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/samples/ControlCatalog/Pages/ContextFlyoutPage.xaml b/samples/ControlCatalog/Pages/ContextFlyoutPage.xaml
index b54b3fbdbf..cc17d9c747 100644
--- a/samples/ControlCatalog/Pages/ContextFlyoutPage.xaml
+++ b/samples/ControlCatalog/Pages/ContextFlyoutPage.xaml
@@ -78,12 +78,13 @@
       </Border>
       <Border x:Name="CancellableContextBorder">
         <Border.ContextFlyout>
-          <Flyout Content="Cancellable flyout" />
+          <Flyout>
+            <CheckBox x:Name="CancelCloseCheckBox" Content="Cancel close" />
+          </Flyout>
         </Border.ContextFlyout>
         <StackPanel>
           <TextBlock Text="Cancellable" />
           <CheckBox x:Name="CancelOpenCheckBox" Content="Cancel open" />
-          <CheckBox x:Name="CancelCloseCheckBox" Content="Cancel close" />
         </StackPanel>
       </Border>
     </UniformGrid>
diff --git a/samples/ControlCatalog/Pages/ContextMenuPage.xaml b/samples/ControlCatalog/Pages/ContextMenuPage.xaml
index 801e4a6c20..7e564efafc 100644
--- a/samples/ControlCatalog/Pages/ContextMenuPage.xaml
+++ b/samples/ControlCatalog/Pages/ContextMenuPage.xaml
@@ -71,13 +71,16 @@
       <Border x:Name="CancellableContextBorder">
         <Border.ContextMenu>
           <ContextMenu>
-            <MenuItem Header="Cancellable flyout" />
+            <MenuItem>
+              <MenuItem.Header>
+                <CheckBox x:Name="CancelCloseCheckBox" Content="Cancel close" />
+              </MenuItem.Header>
+            </MenuItem>
           </ContextMenu>
         </Border.ContextMenu>
         <StackPanel>
           <TextBlock Text="Cancellable" />
           <CheckBox x:Name="CancelOpenCheckBox" Content="Cancel open" />
-          <CheckBox x:Name="CancelCloseCheckBox" Content="Cancel close" />
         </StackPanel>
       </Border>
     </UniformGrid>
diff --git a/src/Avalonia.Controls/ContextMenu.cs b/src/Avalonia.Controls/ContextMenu.cs
index 57e4909e39..ca55fd0bc7 100644
--- a/src/Avalonia.Controls/ContextMenu.cs
+++ b/src/Avalonia.Controls/ContextMenu.cs
@@ -329,6 +329,7 @@ namespace Avalonia.Controls
 
                 _popup.Opened += PopupOpened;
                 _popup.Closed += PopupClosed;
+                _popup.Closing += PopupClosing;
             }
 
             if (_popup.Parent != control)
@@ -355,6 +356,11 @@ namespace Avalonia.Controls
             Focus();
         }
 
+        private void PopupClosing(object sender, CancelEventArgs e)
+        {
+            e.Cancel = CancelClosing();
+        }
+
         private void PopupClosed(object sender, EventArgs e)
         {
             foreach (var i in LogicalChildren)
diff --git a/src/Avalonia.Controls/Flyouts/FlyoutBase.cs b/src/Avalonia.Controls/Flyouts/FlyoutBase.cs
index e4b68c62fd..011af4e7a5 100644
--- a/src/Avalonia.Controls/Flyouts/FlyoutBase.cs
+++ b/src/Avalonia.Controls/Flyouts/FlyoutBase.cs
@@ -151,11 +151,7 @@ namespace Avalonia.Controls.Primitives
 
             if (canCancel)
             {
-                bool cancel = false;
-
-                var closing = new CancelEventArgs();
-                Closing?.Invoke(this, closing);
-                if (cancel || closing.Cancel)
+                if (CancelClosing())
                 {
                     return;
                 }
@@ -195,6 +191,11 @@ namespace Avalonia.Controls.Primitives
                 }
             }
 
+            if (CancelOpening())
+            {
+                return;
+            }
+
             if (Popup.Parent != null && Popup.Parent != placementTarget)
             {
                 ((ISetLogicalParent)Popup).SetParent(null);
@@ -328,6 +329,7 @@ namespace Avalonia.Controls.Primitives
 
             Popup.Opened += OnPopupOpened;
             Popup.Closed += OnPopupClosed;
+            Popup.Closing += OnPopupClosing;
         }
 
         private void OnPopupOpened(object sender, EventArgs e)
@@ -335,9 +337,14 @@ namespace Avalonia.Controls.Primitives
             IsOpen = true;
         }
 
+        private void OnPopupClosing(object sender, CancelEventArgs e)
+        {
+            e.Cancel = CancelClosing();
+        }
+
         private void OnPopupClosed(object sender, EventArgs e)
         {
-            HideCore();
+            HideCore(false);
         }
 
         private void PositionPopup(bool showAtPointer)
@@ -483,6 +490,20 @@ namespace Avalonia.Controls.Primitives
             }            
         }
 
+        private bool CancelClosing()
+        {
+            var eventArgs = new CancelEventArgs();
+            Closing?.Invoke(this, eventArgs);
+            return eventArgs.Cancel;
+        }
+
+        private bool CancelOpening()
+        {
+            var eventArgs = new CancelEventArgs();
+            Opening?.Invoke(this, eventArgs);
+            return eventArgs.Cancel;
+        }
+
         internal static void SetPresenterClasses(IControl presenter, Classes classes)
         {
             //Remove any classes no longer in use, ignoring pseudoclasses
diff --git a/src/Avalonia.Controls/Primitives/Popup.cs b/src/Avalonia.Controls/Primitives/Popup.cs
index b445de0472..f23a27e67a 100644
--- a/src/Avalonia.Controls/Primitives/Popup.cs
+++ b/src/Avalonia.Controls/Primitives/Popup.cs
@@ -1,4 +1,5 @@
 using System;
+using System.ComponentModel;
 using System.Linq;
 using System.Reactive.Disposables;
 using Avalonia.Controls.Presenters;
@@ -154,6 +155,8 @@ namespace Avalonia.Controls.Primitives
         /// </summary>
         public event EventHandler? Opened;
 
+        internal event EventHandler<CancelEventArgs>? Closing;
+
         public IPopupHost? Host => _openState?.PopupHost;
 
         public bool WindowManagerAddShadowHint
@@ -567,6 +570,13 @@ namespace Avalonia.Controls.Primitives
 
         private void CloseCore()
         {
+            var closingArgs = new CancelEventArgs();
+            Closing?.Invoke(this, closingArgs);
+            if (closingArgs.Cancel)
+            {
+                return;
+            }
+
             _isOpenRequested = false;
             if (_openState is null)
             {