Question

我创建了一个自定义附加行为：

public static class CustomItemsBehaviour
{
    public static readonly DependencyProperty MyTestProperty =
     DependencyProperty.RegisterAttached(
         "MyTest",
         typeof(string),
         typeof(ItemsControl),
         new UIPropertyMetadata(""));

     public static string GetMyTest(ItemsControl itemsControl)
     {
        return (string)itemsControl.GetValue(MyTestProperty);
     }

     public static void SetMyTest(ItemsControl itemsControl, string value)
     {
        itemsControl.SetValue(MyTestProperty, value);
     }
}

我试图像这样使用它：

<ListBox
    ItemsSource="{Binding Path=Items}" 
    AttachedBehaviours:CustomItemsBehaviour.MyTest="{Binding TestValue}">

但它失败了：

{"A 'Binding' cannot be set on the 'SetMyTest' property of type 'ListBox'. A 'Binding' can only be set on a DependencyProperty of a DependencyObject."}

我想在视图模型中将某些值绑定到MyTest的值。这可能吗？

Answer 1

问题在于您的注册码。您应该将typeof(CustomItemsBehaviour)作为所有者类型传递：

public static readonly DependencyProperty MyTestProperty =
 DependencyProperty.RegisterAttached(
     "MyTest",
     typeof(string),
     typeof(CustomItemsBehaviour),
     new UIPropertyMetadata(""));

Answer 2

我不确定你想要达到的目标，但我认为你所附属性的声明存在一些错误。试试这个：

public static class CustomItemsBehaviour
{
public static readonly DependencyProperty MyTestProperty =
 DependencyProperty.RegisterAttached(
     "MyTest",
     typeof(string),
     typeof(CustomItemsBehaviour),
     new UIPropertyMetadata(""));

 public static string GetMyTest(DependencyObject itemsControl)
 {
    return (string)itemsControl.GetValue(MyTestProperty);
 }

 public static void SetMyTest(DependencyObject itemsControl, string value)
 {
    itemsControl.SetValue(MyTestProperty, value);
 }

}

请参阅此处DependencyProperty.RegisterAttached

绑定到附加的行为

2 个答案: