Implemented RefreshCellContent on DataGridTemplateColumn

src/Avalonia.DataGrid/DataGridColumns.cs

@@ -1440,7 +1440,7 @@ namespace Avalonia.Controls
 
             DataGridCell dataGridCell = dataGridRow.Cells[dataGridColumn.Index];
             Debug.Assert(dataGridCell != null);
-            if (dataGridCell.Content is Control element)
+            if (dataGridCell.Content is IControl element)
             {
                 dataGridColumn.RefreshCellContent(element, propertyName);
             }

src/Avalonia.DataGrid/DataGridTemplateColumn.cs

@@ -65,5 +65,15 @@ namespace Avalonia.Controls
         {
             return null;
         }
+
+        protected internal override void RefreshCellContent(IControl element, string propertyName)
+        {
+            if(propertyName == nameof(CellTemplate) && element.Parent is DataGridCell cell)
+            {
+                cell.Content = GenerateElement(cell, cell.DataContext);
+            }
+
+            base.RefreshCellContent(element, propertyName);
+        }
     }
 }