Question

我正在尝试使用一些嵌套属性来开发用户控件，这些属性允许使用数据绑定来设置它。例如，我有这样的事情：

// Top level control
public class MyControl : Control
{
    public string TopLevelTestProperty
    {
        get { return (string)GetValue(TopLevelTestPropertyProperty); }
        set { SetValue(TopLevelTestPropertyProperty, value); }
    }

    public static readonly DependencyProperty TopLevelTestPropertyProperty =
        DependencyProperty.Register("TopLevelTestProperty", typeof(string), typeof   
           (MyControl), new UIPropertyMetadata(""));

    // This property contains nested object
    public MyNestedType NestedObject
    {
        get { return (MyNestedType)GetValue(NestedObjectProperty); }
        set { SetValue(NestedObjectProperty, value); }
    }

    public static readonly DependencyProperty NestedObjectProperty =
        DependencyProperty.Register("NestedObject", typeof(MyNestedType), typeof 
            (MyControl), new UIPropertyMetadata(null));
}

// Nested object's type
public class MyNestedType : DependencyObject
{
    public string NestedTestProperty
    {
        get { return (string)GetValue(NestedTestPropertyProperty); }
        set { SetValue(NestedTestPropertyProperty, value); }
    }

    public static readonly DependencyProperty NestedTestPropertyProperty =
        DependencyProperty.Register("NestedTestProperty", typeof(string), typeof
            (MyNestedType), new UIPropertyMetadata(""));
}

// Sample data context
public class TestDataContext
{
    public string Value
    {
        get
        {
            return "TEST VALUE!!!";
        }
    }
}
...
this.DataContext = new TestDataContext();
...

XAML：

      <local:mycontrol x:name="myControl" topleveltestproperty="{Binding Value}" >
         <local:mycontrol.nestedobject>
            <local:mynestedtype x:name="myNestedControl" nestedtestproperty="{Binding Value}" />
         </local:mycontrol.nestedobject>
      </local:mycontrol>

它适用于属性TopLevelTestProperty，但它不适用于NestedTestProperty。似乎嵌套绑定不起作用。有人能帮帮我吗？有没有办法做出这样的约束？我认为这是因为我的嵌套对象没有任何对顶级对象的引用，因此无法使用MyControl的DataContext解析它。

Answer 1

H.B.对，嵌套控件不从mycontrol继承DataContext。 Tyr out明确地设置它：

<local:mycontrol x:name="myControl" 
                 topleveltestproperty="{Binding Value}" >          
   <local:mycontrol.nestedobject>             
           <local:mynestedtype x:name="myNestedControl" 
                               DataContext="{Binding ElementName=myControl,
                                                     Path=DataContext}"
                               nestedtestproperty="{Binding Value}" />          
  </local:mycontrol.nestedobject>       
</local:mycontrol>

WPF Control的嵌套属性的数据绑定

1 个答案: