WPF自定义形状

Question

我需要创建一个自定义形状以添加到WPF表单上.形状只是一个三角形.如果你想知道,是的,我可以用XAML中的Polygon做到这一点:

<Polygon Fill="LightBlue" Stroke="Black" Name="Triangle">
  <Polygon.Points>
    <Point X="0" Y="0"></Point>
    <Point X="10" Y="0"></Point>
    <Point X="5" Y="-10"></Point>
  </Polygon.Points>
</Polygon>

问题是我们需要绑定一个最终决定形状大小的其他地方的属性.所以,我写了一个像这样的形状类的简单扩展:

public class Triangle:Shape
{
    private double size;

    public static readonly DependencyProperty SizeProperty = DependencyProperty.Register("Size", typeof(Double), typeof(Triangle));

    public Triangle() {            
    }

    public double Size
    {
        get { return size; }
        set { size = value; }
    }

    protected override Geometry DefiningGeometry
    {
        get {

            Point p1 = new Point(0.0d,0.0d);
            Point p2 = new Point(this.Size, 0.0d);
            Point p3 = new Point(this.Size / 2, -this.Size);

            List<PathSegment> segments = new List<PathSegment>(3);
            segments.Add(new LineSegment(p1,true));
            segments.Add(new LineSegment(p2, true));
            segments.Add(new LineSegment(p3, true));

            List<PathFigure> figures = new List<PathFigure>(1);
            PathFigure pf = new PathFigure(p1, segments, true);
            figures.Add(pf);

            Geometry g = new PathGeometry(figures, FillRule.EvenOdd, null);

            return g;
        }
    }

}

我认为这很好,但形状没有出现在表格的任何地方.所以,我不确定DefiningGeometry方法是否写得很好.如果我看不到任何可能的事情,那就不是.谢谢!

Answer 1

依赖项属性未正确设置. 像这样写Sizegetter/setter:

public double Size
{
    get { return (double)this.GetValue(SizeProperty); }
    set { this.SetValue(SizeProperty, value); }
}