DependencyProperty和WPF設計器

Question

class MyLine : Shape { 
    public static readonly DependencyProperty X11Property; 
    public static readonly DependencyProperty X22Property; 
    public static readonly DependencyProperty Y11Property; 
    public static readonly DependencyProperty Y22Property; 

    static MyLine() { 
     X11Property = DependencyProperty.Register("X11", typeof(double), typeof(MyLine), new UIPropertyMetadata(double.NaN)); 
     X22Property = DependencyProperty.Register("X22", typeof(double), typeof(MyLine), new UIPropertyMetadata(double.NaN)); 
     Y11Property = DependencyProperty.Register("Y11", typeof(double), typeof(MyLine), new UIPropertyMetadata(double.NaN)); 
     Y22Property = DependencyProperty.Register("Y22", typeof(double), typeof(MyLine), new UIPropertyMetadata(double.NaN)); 
    } 

    [TypeConverter(typeof(LengthConverter))] 
    public double X11 { get { return (double)GetValue(X11Property); } set { SetValue(X11Property, value); } } 
    [TypeConverter(typeof(LengthConverter))] 
    public double X22 { get { return (double)GetValue(X22Property); } set { SetValue(X22Property, value); } } 
    [TypeConverter(typeof(LengthConverter))] 
    public double Y11 { get { return (double)GetValue(Y11Property); } set { SetValue(Y11Property, value); } } 
    [TypeConverter(typeof(LengthConverter))] 
    public double Y22 { get { return (double)GetValue(Y22Property); } set { SetValue(Y22Property, value); } } 

    protected override System.Windows.Media.Geometry DefiningGeometry { 
     get { 
      var geometryGroup = new GeometryGroup(); 

      // Add line 
      geometryGroup.Children.Add(new LineGeometry(new Point(X11, Y11), new Point(X22, Y22))); 
      return geometryGroup; 
     } 
    } 
} 

爲什麼當我更新WPF設計器（VS 2010）中的「myLine」座標時，它不會自動更新它（實時）？

當使用默認的「Line」WPF對象時，它們在XAML代碼在XAML/Design視圖中被更改（編輯）時自動更新。

Answer 1

因爲這些屬性會影響渲染，你應該在元數據中指定：

X11Property = DependencyProperty.Register("X11", typeof(double), typeof(DirectionLine), new FrameworkPropertyMetadata(double.NaN, FrameworkPropertyMetadataOptions.AffectsRender)); 

我不知道這將是足夠的設計者考慮到這一點，但它是值得一試..