您可以向自定义用户控件添加新的依赖项属性并将数据网格项源绑定到该属性.确保处理用户控件数据网格上的选择更改事件并将依赖属性设置为所选项目.

You can add a new dependency property to your custom usercontrol and bind your datagrid items source to that property. Make sure to handle selection changed event on your user control's data grid and set the dependency property to the selected item.

   public object MySelectedItem
        {
            get { return (object)GetValue(MySelectedItemProperty); }
            set { SetValue(MySelectedItemProperty, value); }
        }

    // Using a DependencyProperty as the backing store for MySelectedItem.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty MySelectedItemProperty =
        DependencyProperty.Register("MySelectedItem", typeof(object), typeof(YOURUSERCONTROLTYPE), new UIPropertyMetadata(null));

处理选择更改事件

   public YourUserControl()
        {
            InitializeComponent();
            dgv.SelectionChanged += dgv_SelectionChanged; 

        }

    void dgv_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            MySelectedItem = dgv.SelectedItem;
        }

然后绑定到

ItemsSource="{Binding ElementName=myUserControl, Path=MySelectedItem.CustomerOrders}"