Merge pull request #9921 from almightyju/datagrid-fixes

Fix DataGridTemplateColumn reusing edit control when exiting edit mode

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -4152,6 +4152,7 @@ namespace Avalonia.Controls
 
             if (exitEditingMode)
             {
+                CurrentColumn.EndCellEditInternal();
                 _editingColumnIndex = -1;
                 editingCell.UpdatePseudoClasses();
 

src/Avalonia.Controls.DataGrid/DataGridColumn.cs

@@ -800,11 +800,22 @@ namespace Avalonia.Controls
         protected internal virtual void RefreshCellContent(Control element, string propertyName)
         { }
 
+        /// <summary>
+        /// When overridden in a derived class, called when a cell in the column exits editing mode.
+        /// </summary>
+        protected virtual void EndCellEdit()
+        { }
+
         internal void CancelCellEditInternal(Control editingElement, object uneditedValue)
         {
             CancelCellEdit(editingElement, uneditedValue);
         }
 
+        internal void EndCellEditInternal()
+        {
+            EndCellEdit();
+        }
+
         /// <summary>
         /// Coerces a DataGridLength to a valid value.  If any value components are double.NaN, this method
         /// coerces them to a proper initial value.  For star columns, the desired width is calculated based

src/Avalonia.Controls.DataGrid/DataGridTemplateColumn.cs

@@ -55,17 +55,25 @@ namespace Avalonia.Controls
             get => _cellEditingCellTemplate;
             set => SetAndRaise(CellEditingTemplateProperty, ref _cellEditingCellTemplate, value);
         }
-        
-        private static void OnCellTemplateChanged(AvaloniaPropertyChangedEventArgs e)
+
+        private bool _forceGenerateCellFromTemplate;
+
+        protected override void EndCellEdit()
         {
-            var oldValue = (IDataTemplate)e.OldValue;
-            var value = (IDataTemplate)e.NewValue;
+            //the next call to generate element should not resuse the current content as we need to exit edit mode
+            _forceGenerateCellFromTemplate = true;
+            base.EndCellEdit();
         }
 
         protected override Control GenerateElement(DataGridCell cell, object dataItem)
         {
             if (CellTemplate != null)
             {
+                if (_forceGenerateCellFromTemplate)
+                {
+                    _forceGenerateCellFromTemplate = false;
+                    return CellTemplate.Build(dataItem);
+                }
                 return (CellTemplate is IRecyclingDataTemplate recyclingDataTemplate)
                     ? recyclingDataTemplate.Build(dataItem, cell.Content as Control)
                     : CellTemplate.Build(dataItem);