在自定义控件中绑定 LinearGradientBrush StartPoint

Question

在上一个问题中，kbmax 告诉我如何在我的 generic.xaml 中绑定自定义属性。这个答案在Setting Border background with a template binding

在我尝试使用 LinearGradientBrush StartPoint 执行此操作之前效果很好，这是一个示例：

这显然工作正常：

<LinearGradientBrush StartPoint="0.5,0" EndPoint="0.5,1">

我想将它们绑定到这样的自定义属性： 这不起作用，无论我将属性设置为什么，我总是得到一个从左到右的渐变。

<LinearGradientBrush StartPoint="{Binding HeaderBorderGradientStartPoint, RelativeSource={RelativeSource TemplatedParent}}" EndPoint="{Binding HeaderBorderGradientEndPoint, RelativeSource={RelativeSource TemplatedParent}}">

这是类中的代码。

    public static readonly DependencyProperty HeaderBorderGradientStartPointProperty =
        DependencyProperty.Register("HeaderBorderGradientStartPoint", typeof(Point), typeof(GalleryExpander), new PropertyMetadata(new Point(0.5,0)));
    public Point HeaderBorderGradientStartPoint {
        get { return (Point)GetValue(HeaderBorderGradientStartPointProperty); }
        set { SetValue(HeaderBorderGradientStartPointProperty, value); }
    }

    public static readonly DependencyProperty HeaderBorderGradientEndPointProperty =
        DependencyProperty.Register("HeaderBorderGradientEndPoint", typeof(Point), typeof(GalleryExpander), new PropertyMetadata(new Point(0.5,1)));
    public Point HeaderBorderGradientEndPoint {
        get { return (Point)GetValue(HeaderBorderGradientEndPointProperty); }
        set { SetValue(HeaderBorderGradientEndPointProperty, value); }
    }


<Border.BorderBrush>
    <LinearGradientBrush StartPoint="{Binding HeaderBorderGradientStartPoint, RelativeSource={RelativeSource TemplatedParent}}" EndPoint="{Binding HeaderBorderGradientEndPoint, RelativeSource={RelativeSource TemplatedParent}}">
        <LinearGradientBrush.GradientStops>
            <GradientStop Offset="0.0" Color="Transparent" />
            <GradientStop Offset="0.25" Color="Transparent" />
            <GradientStop Offset="0.50" Color="Transparent" />
            <GradientStop Offset="0.75" Color="Transparent" />
            <GradientStop Offset="1.0" Color="Transparent" />
        </LinearGradientBrush.GradientStops>
    </LinearGradientBrush>
</Border.BorderBrush>

感谢您的任何指导......

Answer 1

嗯，我创建了一个小的自定义控件来检查它，它工作得很好。我的控件如下所示：

public class MyGradientControl : Control
{
    public static readonly DependencyProperty StartPointDProperty =
        DependencyProperty.Register("StartPointD", typeof (Point), 
        typeof (MyGradientControl), new PropertyMetadata(new Point(0.5, 0.5)));

    static MyGradientControl()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof (MyGradientControl), 
            new FrameworkPropertyMetadata(typeof (MyGradientControl)));
    }

    public Point StartPointD
    {
        get { return (Point) GetValue(StartPointDProperty); }
        set { SetValue(StartPointDProperty, value); }
    }
}

并且具有以下样式（在 Themes\generic.xaml 中）：

<Style TargetType="{x:Type local:MyGradientControl}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:MyGradientControl}">
                <Border Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}">
                    <Grid VerticalAlignment="Stretch" 
                          HorizontalAlignment="Stretch">
                        <Grid.Background>
                            <LinearGradientBrush 
                                StartPoint="{Binding StartPointD, 
                                             RelativeSource={RelativeSource 
                                                  TemplatedParent}}" 
                                EndPoint="0, 0">
                                <GradientStop Color="Red" Offset="0"/>
                                <GradientStop Color="White" Offset="1"/>
                            </LinearGradientBrush>
                        </Grid.Background>
                    </Grid>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

你们是否为 LinearGradientBrush 提供 GradientStops？他们有偏移量吗？