WPF（颜色突变）

我们知道可以用LinearGradientBrush实现颜色的渐变，如下图，从Red渐变到Blue：

<Border Grid.Row="1" BorderBrush="Black" BorderThickness="5" CornerRadius="20" >
    <Border.Background>
        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
            <GradientStop Color="Red" Offset="0"/>
            <GradientStop Color="Blue" Offset="1"/>
        </LinearGradientBrush>
    </Border.Background>
</Border>

但是如何做到颜色的突变，就时从Red直接变为Blue呢？？？

还是利用 LinearGradientBrush，但是要利用4个渐变点：

<Border Grid.Row="1" BorderBrush="Black" BorderThickness="5" CornerRadius="20" >
    <Border.Background>
        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
            <GradientStop Color="Red" Offset="0"/>
            <GradientStop Color="Red" Offset="0.5"/>
            <GradientStop Color="Blue" Offset="0.5"/>
            <GradientStop Color="Blue" Offset="1"/>
        </LinearGradientBrush>
    </Border.Background>
</Border>