Merge pull request #5931 from Deadpikle/patch-1

Default DataGrid SelectedIndex & SelectedItem binding mode to TwoWay

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -535,7 +535,8 @@ namespace Avalonia.Controls
             AvaloniaProperty.RegisterDirect<DataGrid, int>(
                 nameof(SelectedIndex),
                 o => o.SelectedIndex,
-                (o, v) => o.SelectedIndex = v);
+                (o, v) => o.SelectedIndex = v,
+                defaultBindingMode: BindingMode.TwoWay);
 
         /// <summary>
         /// Gets or sets the index of the current selection.
@@ -553,7 +554,8 @@ namespace Avalonia.Controls
             AvaloniaProperty.RegisterDirect<DataGrid, object>(
                 nameof(SelectedItem),
                 o => o.SelectedItem,
-                (o, v) => o.SelectedItem = v);
+                (o, v) => o.SelectedItem = v,
+                defaultBindingMode: BindingMode.TwoWay);
 
         /// <summary>
         /// Gets or sets the data item corresponding to the selected row.