Question

我目前正在尝试在依赖项值更改时获取更新视图。

我已将视图中的代码复制到其父级中，并且未使用该依赖项，并且工作正常。我相信我的问题在于我如何创建DependencyProperty。

public partial class CULabelConfigControl : UserControl {

    private CreditUnion CU { get; set; }

    public static readonly DependencyProperty CUProperty = DependencyProperty.Register(
        "CU",
        typeof(CreditUnion),
        typeof(CULabelConfigControl),
        new FrameworkPropertyMetadata(null)
    );

我目前在运行时收到错误：

"A 'Binding' cannot be set on the 'CU' property of type 'CULabelConfigControl'. 
 A 'Binding' can only be set on a DependencyProperty of a DependencyObject."

正确方向的任何一点都会有所帮助。如果我需要分享任何其他细节，请告诉我。

Answer 1

它应该是这样的：

public partial class CULabelConfigControl : UserControl
{
    public static readonly DependencyProperty CUProperty =
        DependencyProperty.Register(
            nameof(CU),
            typeof(CreditUnion),
            typeof(CULabelConfigControl));

    public CreditUnion CU
    {
        get { return (CreditUnion)GetValue(CUProperty); }
        set { SetValue(CUProperty, value); }
    }
}

在UserControl的XAML中，您可以通过将UserControl指定为RelativeSource来绑定此属性，例如

<Label Content="{Binding CU, RelativeSource={RelativeSource AncestorType=UserControl}}"/>

如果需要在属性值更改时在UserControl类中收到通知，则应注册PropertyChangedCallback：

public static readonly DependencyProperty CUProperty =
    DependencyProperty.Register(
        nameof(CU),
        typeof(CreditUnion),
        typeof(CULabelConfigControl),
        new PropertyMetadata(CUPropertyChanged));

private static void CUPropertyChanged(
    DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
    var control = (CULabelConfigControl)obj;

    // react on value change here
}

更改更新控制上的WPF依赖项属性

1 个答案: