在 Style.Resources 中使用 StaticResourceExtension 时出错 [英] Error when using StaticResourceExtension inside Style.Resources

问题描述

我在模板中使用 DynamicResource，并在使用该模板的每个样式中使用 StaticResourceExtensions 作为资源，以便在每个样式中对 DynamicResource 进行不同的评估.

I am using DynamicResource in a template, and StaticResourceExtensions as resource inside each style using that template, so that the DynamicResource is evaluated differently in each of them them.

问题是，我收到此错误:

The problem is, I get this error:

Unable to cast object of type 'System.Windows.Media.Effects.DropShadowEffect' to type 'System.Windows.ResourceDictionary'

这是我的代码:

<DropShadowEffect 
    x:Key="Sombra" 
    Opacity="0.5" 
    ShadowDepth="3" 
    BlurRadius="5"
/>

<ControlTemplate 
    x:Key="ControleGeometriaTemplate"
    TargetType="{x:Type Control}"
>
    <Border
        x:Name="border"
        Background="{TemplateBinding Background}"
        Width="{TemplateBinding Width}"
        Height="{TemplateBinding Height}"
    />
        <Path
            x:Name="ícone"
            Fill="{TemplateBinding Foreground}"
            Effect="{DynamicResource PathShadow}"
        />
    </Border>
</ControlTemplate>

<Style x:Key="BotãoGeometria" TargetType="{x:Type ButtonBase}">
    <Setter Property="Template" Value="{StaticResource ControleGeometriaTemplate}"/>
</Style>

<Style 
    x:Key="BotãoNavegaçãoBase" 
    TargetType="{x:Type ButtonBase}" 
    BasedOn="{StaticResource BotãoGeometria}"
>
    <Style.Resources>
        <StaticResource x:Key="PathShadow" ResourceKey="Sombra"/>
    </Style.Resources>      
</Style>

推荐答案

据我所知 StaticResourceExtension 在 某些情况.

感觉你发现了类似的情况:

It smells like you found a similar situation:

<SolidColorBrush x:Key="RedBrush" Color="Red" />
<Style TargetType="TextBox" x:Key="Test">
    <Style.Resources>
        <StaticResourceExtension x:Key="NewRedBrushKey" ResourceKey="RedBrush" />
    </Style.Resources>
</Style>

在 Window 中使用 Test 样式足以重现您的问题.

Using the Test style in your Window is enough to reproduce your issue.

所以我的建议是使用你自己的扩展:

So my suggestion is to use your own extension:

public class ResourceFinder : System.Windows.Markup.MarkupExtension
{
    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        FrameworkElement frameworkElement;
        IDictionary dictionary;
        IRootObjectProvider rootObjectProvider = (IRootObjectProvider)
            serviceProvider.GetService(typeof(IRootObjectProvider));

        if (rootObjectProvider != null) 
        {
            dictionary = rootObjectProvider.RootObject as IDictionary;

            if (dictionary != null)
            {
                return dictionary[ResourceKey];
            }
            else
            {
                frameworkElement = rootObjectProvider.RootObject as FrameworkElement;
                if (frameworkElement != null)
                {
                    return frameworkElement.TryFindResource(ResourceKey);
                }
            }

        }

        return null;
    }


    public object ResourceKey
    {
        get;
        set;
    }
}

那么你的风格就会变成:

Then your style will become:

<Style 
    x:Key="BotãoNavegaçãoBase" 
    TargetType="{x:Type ButtonBase}" 
    BasedOn="{StaticResource BotãoGeometria}">
    <Style.Resources>
        <local:ResourceFinder x:Key="PathShadow" ResourceKey="Sombra" />
    </Style.Resources>
</Style>

我希望这可以帮助您解决问题.

I hope this can help you with your issue.

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