c# - 在 WPF 自定义控件上多次应用 DropShadowEffect

Question

我正在编写一个 WPF 自定义控件，它显示加载过程的叠加层。此自定义控件源自 ContentControl并重复使用它的 Effect显示投影的依赖属性。

然而，投影意外且意外地显示了两次。我试图找到任何逻辑，但不知道如何解决这个问题。有人知道如何去除外边框上的阴影吗？

LoadingOverlay.cs

public class LoadingOverlay : ContentControl
{
    static LoadingOverlay()
    {
        Type currentType = typeof(LoadingOverlay);
        FrameworkElement.DefaultStyleKeyProperty.OverrideMetadata(
            currentType,
            new FrameworkPropertyMetadata(currentType));
    }
}

Themes\Generic.xaml

<Style TargetType="local:LoadingOverlay">
    <Setter Property="Background" Value="#BBFFFFFF" />
    <Setter Property="BorderBrush" Value="#FF266ECC" />
    <Setter Property="BorderThickness" Value="1" />
    <Setter Property="Effect">
        <Setter.Value>
            <DropShadowEffect ShadowDepth="0" />
        </Setter.Value>
    </Setter>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="local:LoadingOverlay">
                <Border Background="{TemplateBinding Background}" Effect="{x:Null}">
                    <Border Effect="{TemplateBinding Effect}" HorizontalAlignment="Center" VerticalAlignment="Center" Background="#FFFFFFFF" BorderBrush="#FF266ECC" BorderThickness="1">
                        <ContentPresenter VerticalAlignment="Center" Margin="15" RecognizesAccessKey="True" />
                    </Border>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Answer 1

尝试在内部边框级别设置效果，而不是在 LoadingOverlay 级别设置效果。那么您也不必将上边框效果设置为 {x:null} 。见下文:

<Style TargetType="local:LoadingOverlay">
<Setter Property="Background" Value="#BBFFFFFF" />
<Setter Property="BorderBrush" Value="#FF266ECC" />
<Setter Property="BorderThickness" Value="1" />
<Setter Property="Template">
    <Setter.Value>
        <ControlTemplate TargetType="local:LoadingOverlay">
            <Border Background="{TemplateBinding Background}">
                <Border HorizontalAlignment="Center" VerticalAlignment="Center" Background="#FFFFFFFF" BorderBrush="#FF266ECC" BorderThickness="1">
                    <ContentPresenter VerticalAlignment="Center" Margin="15" RecognizesAccessKey="True" />
                    <Border.Effect>
                        <DropShadowEffect ShadowDepth="0" />
                    </Border.Effect>
                </Border>
            </Border>
        </ControlTemplate>
    </Setter.Value>
</Setter>