C# Devexpress如何编码CheckBox列标题以选择或取消选择全部

GridViewColumn checkBoxColumn = new GridViewColumn();
checkBoxColumn.Header = "全选";
checkBoxColumn.Width = 50;
checkBoxColumn.CellTemplate = new DataTemplate(typeof(CheckBox));
gridView.Columns.Add(checkBoxColumn);

DataTemplate headerTemplate = new DataTemplate(typeof(TextBlock));
FrameworkElementFactory checkBoxFactory = new FrameworkElementFactory(typeof(CheckBox));
checkBoxFactory.SetValue(CheckBox.IsCheckedProperty, new Binding("IsCheckedAll"));
checkBoxFactory.AddHandler(CheckBox.CheckedEvent, new RoutedEventHandler(SelectAll_Checked));
checkBoxFactory.AddHandler(CheckBox.UncheckedEvent, new RoutedEventHandler(SelectAll_Unchecked));
headerTemplate.VisualTree = checkBoxFactory;
checkBoxColumn.HeaderTemplate = headerTemplate;

private void SelectAll_Checked(object sender, RoutedEventArgs e)
{
    foreach (var item in gridView.ItemsSource)
    {
        // 设置每一行的选择状态为选中
        // 例如：item.IsChecked = true;
    }
}

private void SelectAll_Unchecked(object sender, RoutedEventArgs e)
{
    foreach (var item in gridView.ItemsSource)
    {
        // 设置每一行的选择状态为未选中
        // 例如：item.IsChecked = false;
    }
}