具有相对尺寸的RectangleGeometry ......怎么样？

Question

我正试图在我正在创建的按钮的控制模板上复制如今时尚的"反射"效果.

基本思想是创建一个矩形,其渐变填充从白色到透明,然后用矩形几何体剪切一些半透明矩形.

问题是我不知道如何定义相对矩形几何.我通过定义一个大值(1000)来解决宽度问题,但高度是一个问题.例如,它适用于高度为200的按钮,但对于较小的按钮不起作用.

有任何想法吗？

            <Rectangle RadiusX="5" RadiusY="5" StrokeThickness="1" Stroke="Transparent">
                <Rectangle.Fill>
                    <LinearGradientBrush StartPoint="0,0" EndPoint="0,0.55">
                        <GradientStop Color="#66ffffff" Offset="0.0"  />
                        <GradientStop Color="Transparent" Offset="1.0" />
                    </LinearGradientBrush>
                </Rectangle.Fill>
                <Rectangle.Clip>
                    <RectangleGeometry Rect="0,0,1000,60" />
                </Rectangle.Clip>
            </Rectangle>

Answer 1

你可以用一个MultiBinding和一个新的IMultiValueConverter:

public class RectangleConverter : IMultiValueConverter
{
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
        // you can pass in the value to divide by if you want
        return new Rect(0, 0, (double)values[0], (double)values[1] / 3.33);
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        throw new NotSupportedException();
    }
}

并在你的XAML中使用如下:

<lcl:RectangleConverter x:Key="rectConverter" />

...

<RectangleGeometry>
    <RectangleGeometry.Rect>
        <MultiBinding Converter="{StaticResource rectConverter}">
            <Binding Path="ActualWidth" RelativeSource="{RelativeSource AncestorType={x:Type Button}}" />
            <Binding Path="ActualHeight" RelativeSource="{RelativeSource AncestorType={x:Type Button}}" />
        </MultiBinding>
    </RectangleGeometry.Rect>
</RectangleGeometry>