DataTrigger中的WPF自定义附加属性

时间:2010-08-18 16:26:04

标签: .net wpf data-binding attached-properties

我在SO上看过类似的问题并且无法得到解决方案,所以这是我的交易:

**我有以下课程:**

public static class ControlSecurity
{
    public static readonly DependencyProperty IsSecuredProperty =
        DependencyProperty.RegisterAttached(
            "IsSecured",
            typeof (bool),
            typeof (FrameworkElement),
            new PropertyMetadata(false));

    [AttachedPropertyBrowsableForType(typeof(Control))]
    public static bool GetIsSecured(FrameworkElement ctl)
    {
        return (bool)ctl.GetValue(IsSecuredProperty);
    }

    public static void SetIsSecured(FrameworkElement ctl, bool value)
    {
        ctl.SetValue(IsSecuredProperty, value);
    }
}

正如您所猜测的那样,它会为所有Security:ControlSecurity.IsSecured添加FrameworkElement

注意:Security:指向所有这些类所在的命名空间(包括ControlSecurity

所以我实现了这个数据模板&我的一个控件的样式:

       <DataTemplate x:Key="SecureButtonTemplate">
            <StackPanel Orientation="Horizontal">
                <Image x:Name="SecureIcon" Source="pack://application:,,,/Resources/Icons/secure.png" Width="16" Height="16" Visibility="Collapsed" />
                <ContentPresenter Content="{Binding}" />
            </StackPanel>
            <DataTemplate.Triggers>
                <DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Button}}, Path=Security:ControlSecurity.IsSecured}" Value="true">
                    <Setter TargetName="SecureIcon" Property="Visibility" Value="Visible" />
                </DataTrigger>
            </DataTemplate.Triggers>
        </DataTemplate>
        <Style TargetType="{x:Type Button}">
            <Setter Property="ContentTemplate" Value="{StaticResource SecureButtonTemplate}" />
        </Style>

这里的问题在于DataTrigger

上的绑定
{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Button}}, Path=Security:ControlSecurity.IsSecured}

我的想法是,我想找到父按钮,然后绑定到我定义的Security:ControlSecurity.IsSecured附加属性。

我在这个绑定上尝试了大约10种不同的变体,我不断得到一个像这样的绑定错误:

System.Windows.Data Error: 40 : BindingExpression path error: 'Security:ControlSecurity' property not found on 'object' ''Button' (Name='')'. BindingExpression:Path=Security:ControlSecurity.IsSecured; DataItem='Button' (Name=''); target element is 'ContentPresenter' (Name=''); target property is 'NoTarget' (type 'Object')

我在这一点上很难过,并且非常喜欢WPF专家的一些见解。

1 个答案:

答案 0 :(得分:11)

只需添加括号:

Path=(Security:ControlSecurity.IsSecured)