Question

我正在尝试通过XAML将依赖项属性绑定到我的自定义WPF控件。

以下是我如何注册依赖属性：

public static readonly DependencyProperty AltNamesProperty = 
    DependencyProperty.Register ("AltNames", typeof(string), typeof(DefectImages));

public string AltNames
{
    get { return (string) GetValue(AltNamesProperty); }
    set { SetValue(AltNamesProperty, value); }
}

以下是我在XAML中的称呼方式：

<DataGrid.Columns>                
    <DataGridTemplateColumn IsReadOnly="True">
        <DataGridTemplateColumn.CellTemplate>
            <DataTemplate>
                <StackPanel Name="StackPanel1" Grid.Column="0" Width="950">
                    <TextBlock FontSize="16" TextDecorations="None" Text="{BindingPath=StandardName}" Foreground="Black"  FontWeight="Bold" Padding="5,10,0,0"></TextBlock>
                    <TextBlock Text="{Binding Path=AltNames}"TextWrapping="WrapWithOverflow" Padding="5,0,0,10"></TextBlock>
                    <!-- this part should be magic!! -->
                    <controls:DefectImages AltNames="{Binding Path=AltNames}"></controls:DefectImages>
                </StackPanel>
            </DataTemplate>
        </DataGridTemplateColumn.CellTemplate>
    </DataGridTemplateColumn>
</DataGrid.Columns>

我知道我尝试绑定的AltNames属性是一个有效的属性，因为我可以在文本块中显示它。我是否错误地注册了Dependency属性？

我需要做些什么才能在后面的代码中为AltNames分配正确的值？

Answer 1

感谢@Danko让我入门。我注册了一个回调来设置属性更改时的值这就是我最终的结果：

private static void OnDefectIdChanged(DependencyObject defectImageControl, DependencyPropertyChangedEventArgs eventArgs)
{
  var control = (DefectImages) defectImageControl;
  control.DefectID = (Guid)eventArgs.NewValue;
}

/// <summary>
/// Registers a dependency property, enables us to bind to it via XAML
/// </summary>
public static readonly DependencyProperty DefectIdProperty = DependencyProperty.Register(
    "DefectID",
    typeof (Guid),
    typeof (DefectImages),
    new FrameworkPropertyMetadata(
      // use an empty Guid as default value
      Guid.Empty,
      // tell the binding system that this property affects how the control gets rendered
      FrameworkPropertyMetadataOptions.AffectsRender, 
      // run this callback when the property changes
      OnDefectIdChanged 
      )
    );

/// <summary>
/// DefectId accessor for for each instance of this control
/// Gets and sets the underlying dependency property value
/// </summary>
public Guid DefectID
{
  get { return (Guid) GetValue(DefectIdProperty); }
  set { SetValue(DefectIdProperty, value); }
}

Answer 2

如果属性影响控件的呈现方式，可能需要为PropertyMetadata指定DependencyProperty.Register参数。例如：

DependencyProperty.Register("AltNames", typeof(string), typeof(DefectImages), 
                              new FrameworkPropertyMetadata( null,
                              FrameworkPropertyMetadataOptions.AffectsRender ) );

未设置WPF依赖项属性

2 个答案: