c# - 使 VisualTreeHelper.HitTest 在单元测试中工作？

Question

我想在某些形状上使用 WPF HitTest 功能而不在屏幕上显示它们。这可能吗？此代码无法按我预期的方式工作。我该如何进行这项工作？

[Test, Ignore, RequiresSTA]
public void VerifyFillContains()
{
    // make a simple triangle:
    var seg1 = new System.Windows.Media.LineSegment(new Point(0.2, 0.1), false);
    var seg2 = new System.Windows.Media.LineSegment(new Point(0.3, 0.8), false);
    var figure = new PathFigure(new Point(0.7, 0.5), new List<PathSegment>{seg1, seg2}, true);

    var sg = new PathGeometry();
    sg.Figures.Add(figure);

    if (sg.CanFreeze)
        sg.Freeze();

    // these don't work:
    Assert.IsFalse(sg.FillContains(new Point()));
    Assert.IsFalse(sg.FillContains(new Point(1.0, 1.0)));
    Assert.IsTrue(sg.FillContains(new Point(0.5, 0.5)));

    var path = new Path { Data = sg, Fill = Brushes.Black };
    path.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
    path.Arrange(new Rect(path.DesiredSize));

    // and these don't work:
    var result = VisualTreeHelper.HitTest(path, new Point(0.0, 0.0));
    Assert.IsFalse(result != null && Equals(result.VisualHit, path));
    result = VisualTreeHelper.HitTest(path, new Point(1.0, 1.0));
    Assert.IsFalse(result != null && Equals(result.VisualHit, path));
    result = VisualTreeHelper.HitTest(path, new Point(0.5, 0.5));
    Assert.IsTrue(result != null && Equals(result.VisualHit, path));
}

Answer 1

HitTest 基于元素的呈现，因此您应该测量和排列形状。例如

shape.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
shape.Arrange(new Rect(shape.DesiredSize));

或者您可以只使用 FillContains几何的方法。例如

var result = shape.Data.FillContains(ToPoint(target));