c# - WPF UIElement 刷新错误？

Question

我有一个自定义面板，用来绘制选区效果；但有时它不会清除以前的矩形，如果在屏幕足够大(跨两个显示器)时来回移动鼠标，这是 WPF 错误或限制吗？你知道如何解决这个问题吗？提前致谢。

简化后的代码如下所示

public class CustomPanel : Panel
{
    private Rectangle _rectangle;

    public CustomPanel()
    {
        this._rectangle = new Rectangle();
        this._rectangle.StrokeThickness = 3;
        this._rectangle.Stroke = new SolidColorBrush(Color.FromArgb(220, 0, 0, 0)); ;
        this.Children.Add(this._rectangle);
    }            

    protected override Size MeasureOverride(Size availableSize)
    {
        this._rectangle.Measure(availableSize);
        return this._rectangle.DesiredSize;
    }

    protected override Size ArrangeOverride(Size finalSize)
    {
        if (!finalSize.IsEmpty)
        {
            this._rectangle.Arrange(new Rect(new Point(0, 0), finalSize));
        }
        return finalSize;
    }
}        

然后我把它放在一个网格中，并在鼠标移动时使它无效，就像这样

 void OnMouseMove(object sender, MouseEventArgs e)
    {
        var point = e.GetPosition(this);
        var size = new Size(point.X>=0? point.X:0, point.Y>=0? point.Y:0);
        this.Selection.Measure(size);
        this.Selection.Arrange(new Rect(size));

    }

结果如下图所示

Answer 1

试试 UIElement.InvalidateVisual();