Question

我是WPF的新手。我面临以下问题。我有一个用户控件，这是用户控制代码

CustomControl代码

public partial class CustomCanvas : UserControl
{
    public CustomCanvas()
    {
        InitializeComponent();
        DrawCanvas();
    }

    private void DrawCanvas()
    {
        //TODO:
        //Get the Dictionary Value from Parent Bound Property
    }

    public Dictionary<string, List<Shapes>> ShapesData
    {
        get { return (Dictionary<string, List<Shapes>>)GetValue(ShapesDataProperty); }
        set { SetValue(ShapesDataProperty, value); }
    }

    public static readonly DependencyProperty ShapesDataProperty =
        DependencyProperty.Register("ShapesData", typeof(Dictionary<string, List<Shapes>>), typeof(CustomCanvas), new PropertyMetadata(ShapesDataChanged));

    private static void ShapesDataChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var value = e.NewValue;
    }
}

主窗口代码

<Grid>
    <uc:CustomCanvas ShapesData="{Binding ShData}" ></uc:CustomCanvas>
</Grid>

ShapesData的值受以下代码约束。

ShData = new Dictionary<string, List<Shapes>>()
        {
            {"Week 1", new List<Shapes>() {Shapes.Circle, Shapes.Rectangle}},
            {"Week 2", new List<Shapes>() {Shapes.Circle}},
            {"Week 3", new List<Shapes>() {Shapes.Rectangle}}
        };

现在我的问题是在CustomControl DrawCanvas 方法中我想获取父级中的有界值。任何人都可以指导我。

P.S ：我知道如何使用相对RelativeSource和Mode作为FindAncestor将此值绑定在child中。在这里，我想获取值并处理该词典数据。在 ShapesDataChanged 中，我可以轻松访问数据，但问题是在DrawCanvas函数中获取它。

提前致谢。

Answer 1

您可以使用DependencyObject的GetValue（）方法。

var theValueYouNeeded = CustomCanvas.GetValue(ShapesDataProperty);
Dictionary<string, List<Shapes>> value = (Dictionary<string, List<Shapes>>)theValueYouNeeded;
....

在UserControl代码后面获取依赖属性值

1 个答案: