WPF 矩形 - 圆化顶角

Question

如何让 WPF 矩形的顶角变成圆角？

我创建了一个边框并设置了 CornerRadius 属性，并在边框内添加了矩形，但它不起作用，矩形不是圆角的。

<Border BorderThickness="1" CornerRadius="50,50,0,0" BorderBrush="Black">
    <Rectangle Fill="#FF5A9AE0" Stretch="UniformToFill" ClipToBounds="True"/>
</Border>

Answer 1

您遇到的问题是矩形“溢出”了边框的圆角。

矩形不能有单独的圆角，因此如果您只需将背景颜色放在边框上并删除矩形：

<Border BorderThickness="1" Grid.Row="0" Grid.ColumnSpan="2"
        CornerRadius="50,50,0,0" BorderBrush="Black" Background="#FF5A9AE0">
</Border>

您将获得所需的效果。

Answer 2

在矩形上设置 RadiusX 和 RadiusY 属性，这将给它圆角

Answer 3

很好的例子，如何使用 DrawingContext 进行 OnRender：

   /// <summary>
    /// Draws a rounded rectangle with four individual corner radius
    /// </summary>
    public static void DrawRoundedRectangle(this DrawingContext dc, Brush brush,
        Pen pen, Rect rect, CornerRadius cornerRadius)
    {
        var geometry = new StreamGeometry();
        using (var context = geometry.Open())
        {
            bool isStroked = pen != null;
            const bool isSmoothJoin = true;

            context.BeginFigure(rect.TopLeft + new Vector(0, cornerRadius.TopLeft), brush != null, true);
            context.ArcTo(new Point(rect.TopLeft.X + cornerRadius.TopLeft, rect.TopLeft.Y), 
                new Size(cornerRadius.TopLeft, cornerRadius.TopLeft),
                90, false, SweepDirection.Clockwise, isStroked, isSmoothJoin);
            context.LineTo(rect.TopRight - new Vector(cornerRadius.TopRight, 0), isStroked, isSmoothJoin);
            context.ArcTo(new Point(rect.TopRight.X, rect.TopRight.Y + cornerRadius.TopRight), 
                new Size(cornerRadius.TopRight, cornerRadius.TopRight),
                90, false, SweepDirection.Clockwise, isStroked, isSmoothJoin);
            context.LineTo(rect.BottomRight - new Vector(0, cornerRadius.BottomRight), isStroked, isSmoothJoin);
            context.ArcTo(new Point(rect.BottomRight.X - cornerRadius.BottomRight, rect.BottomRight.Y), 
                new Size(cornerRadius.BottomRight, cornerRadius.BottomRight),
                90, false, SweepDirection.Clockwise, isStroked, isSmoothJoin);
            context.LineTo(rect.BottomLeft + new Vector(cornerRadius.BottomLeft, 0), isStroked, isSmoothJoin);
            context.ArcTo(new Point(rect.BottomLeft.X, rect.BottomLeft.Y - cornerRadius.BottomLeft), 
                new Size(cornerRadius.BottomLeft, cornerRadius.BottomLeft),
                90, false, SweepDirection.Clockwise, isStroked, isSmoothJoin);

            context.Close();
        }
        dc.DrawGeometry(brush, pen, geometry);
    }

信息来自：
http://wpftutorial.net/DrawRoundedRectangle.html

Answer 4

即使里面有矩形（或其他任何东西），这个也可以工作：

<Border>
    <Border.OpacityMask>
        <VisualBrush>
            <VisualBrush.Visual>
                <Border CornerRadius="5" Height="100" Width="100" Background="White"/>
            </VisualBrush.Visual>
        </VisualBrush>
    </Border.OpacityMask>

    // put your rounded content here

</Border>

如果你没有内容的精确大小，你将不得不使用高度和宽度。