WPF 附加属性数据绑定 [英] WPF Attached Property Data Binding

问题描述

我尝试使用带有附加属性的绑定.但无法让它工作.

I try to use binding with an attached property. But can't get it working.

public class Attached
{
    public static DependencyProperty TestProperty =
        DependencyProperty.RegisterAttached("TestProperty", typeof(bool), typeof(Attached),
        new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault | FrameworkPropertyMetadataOptions.Inherits));

    public static bool GetTest(DependencyObject obj)
    {
        return (bool)obj.GetValue(TestProperty);
    }

    public static void SetTest(DependencyObject obj, bool value)
    {
        obj.SetValue(TestProperty, value);
    }
}

XAML 代码:

<Window ...>
    <StackPanel local:Attached.Test="true" x:Name="f">
        <CheckBox local:Attached.Test="true" IsChecked="{Binding (local:Attached.Test), Mode=TwoWay, RelativeSource={RelativeSource Self}}" />
        <CheckBox local:Attached.Test="true" IsChecked="{Binding (local:Attached.Test), Mode=TwoWay}" />
    </StackPanel>
</Window>

还有绑定错误:

System.Windows.Data Error: 40 : BindingExpression path error: '(local:Attached.Test)' property not found on 'object' ''StackPanel' (Name='f')'. BindingExpression:Path=(local:Attached.Test); DataItem='StackPanel' (Name='f'); target element is 'CheckBox' (Name=''); target property is 'IsChecked' (type 'Nullable`1')

推荐答案

信不信由你，只需添加 Path= 并在绑定到附加属性时使用括号:

Believe it or not, just add Path= and use parenthesis when binding to an attached property:

IsChecked="{Binding Path=(local:Attached.Test), Mode=TwoWay, RelativeSource={RelativeSource Self}}"

此外，您对 RegisterAttached 的调用应该传入Test"作为属性名称，而不是TestProperty".

In addition, your call to RegisterAttached should pass in "Test" as the property name, not "TestProperty".

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