WPF UserControls：即使使用'x：Shared =" False"'，图片也会消失 [英] WPF UserControls: Image disappears even with 'x:Shared="False"'

问题描述

我在 ResourceDictionary 中为带有图像的按钮定义了一个样式：

I defined a style in a ResourceDictionary for a button with an image:

<Style x:Key="BotonIrAInicioStyle" TargetType="Button">
    <Setter Property="Margin" Value="0"/>
    <Setter Property="Width" Value="{Binding RelativeSource={RelativeSource Self}, Path=ActualHeight}"/>
    <Setter Property="Content">
        <Setter.Value>
            <Image Margin="2" Source="{StaticResource IconoDashboardBlanco}" MaxHeight="20" Stretch="Uniform"
                   RenderOptions.BitmapScalingMode="HighQuality"/>
        </Setter.Value>
    </Setter>
</Style>

图像源在另一个 ResourceDictionary 中定义在同一个程序集中，标记为 x：Shared =False：

The image source is defined in another ResourceDictionary in the same assembly, and marked as x:Shared="False":

<BitmapImage x:Key="IconoDashboardBlanco" x:Shared="False"
UriSource="pack://application:,,,/QualityFramework;component/Images/dashboard64X64.png"/>

由于样式将用于不同的程序集，我使用 pack：// application：,,,表示引用图像。图像的 Build Action 设置为资源（不要复制到输出目录）。

Since the style will be used in a different assembly, I used the "pack://application:,,," notation to reference the image. The Build Action for the image is set to Resource (Do not copy to output directory).

在主程序集中，我有两个 UserControls ，它显示一个风格相同的按钮：

In the main assembly I have two UserControls which display a button with identical style:

<Button DockPanel.Dock="Left" Style="{StaticResource BotonIrAInicioStyle}" Click="BotonIrAInicio_Click"/> (Click event has nothing to do with the problem)

问题：

我打开 UserControl A 包含带有图像的按钮，图像显示正常。然后我打开 UserControl B 包含一个相同的按钮，图像确定。我再次打开 UserControl A ，图像消失了。如果我打开 UserControl B 然后 UserControl A ，则会发生相同的情况，最后一个拥有图像。

I open UserControl A containing the button with the image and the image is displayed ok. Then I open UserControl B containing an identical button, image ok. I open UserControl A again, and the image is gone. Happens the same if I open UserControl B and then UserControl A, the last one "owns" the image.

我到处都是，所有解决方案都指向 x：Shared =False， URI表示法和构建操作 ...我应用了所有这些并且问题仍然存在。我也尝试过清洁和重建但没有成功。

I went everywhere and all the solutions point to the x:Shared="False", the URI notation and the Build Action... I applied all of them and the problem still happens. I also tried cleaning and rebuilding with no success.

我缺少什么？谢谢！

PS：如果我将两个按钮的内容直接设置为图像，它可以正常工作，但整个造型点就是避免这一点！

PS: if I set the content of both buttons to the image directly it works ok, but the whole point of styling is to avoid exactly that!

推荐答案

问题不在于 BitmapImage 它是按钮设置器中的内容 - 它创建一次，因此必须在实例之间跳转。

The problem is not the BitmapImage it's the content in the setter of the button - it's created once and thus has to "jump" between instances.

简单但不是WPF-isque的解决方案是设置 x：共享样式上的假。

The easy, but not WPF-isque, solution is setting x:Shared="False" on the style.

正确的方法是使用 ControlTemplate 或 DataTemplate 。

根据您的观察：

如果我将两个按钮的内容直接设置到图像上就可以正常工作 - 这是因为这样做可以创建两个不同的 Image实例对象。

"if I set the content of both buttons to the image directly it works ok" - this is because to do that you create two different instances of Image object.

但是，这个：造型的全部要点就是避免错误！是一种误解 - 样式并不意味着设置内容控件的内容，c内容取决于上下文。如果你有一个重复所有按钮的视觉效果（不依赖于内容），它应该位于按钮的 ControlTemplate 中。如果您的视觉效果取决于内容（但内容不是视觉效果），则它应位于 DataTemplate 。

But, this: "the whole point of styling is to avoid exactly that!" is a misconception - styles are not meant to set the content of content controls, the content is dependent upon the context. If you have a visual that is repeating for all buttons (without dependency upon the content), it should reside in ControlTemplate for the button. If you have a visual that is dependent upon the content (but the content is not the visual) it should reside in DataTemplate.

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