在WPF应用程序中使用.NET Standard程序集中的内容文件 [英] Use a Content File from a .NET Standard assembly in a WPF application

问题描述

我想将文件嵌入.NET Standard程序集中，并在WPF应用程序的XAML中使用它.

如果将生成操作设置为 Resource ，则很容易在其他程序集中使用嵌入式文件，但是必须使用< Project Sdk ="Microsoft.NET.Sdk.WindowsDesktop> 和< UseWPF> true</UseWPF> 即可使用 Resource 构建操作，如下所示:

 < PropertyGroup>< TargetFramework> netcoreapp3.1</TargetFramework>< UseWPF> true</UseWPF></PropertyGroup>< ItemGroup>< Resource Include ="Resources \ Image.png"/></ItemGroup> 

然后您可以在另一个程序集中使用此Uri:

  pack://application:,,/ReferencedAssembly; component/Resources/Image.png 

如此处所示:

https://docs.microsoft.com/zh-cn/dotnet/framework/wpf/app-development/pack-uris-in-wpf#resource-file-pack-uris

我的问题:

如果仅需要< Project Sdk ="Microsoft.NET.Sdk"> ，并且不希望< UseWPF> true</UseWPF> 您必须使用 Content 构建操作，因为它不需要WPF，如下所示:

https://docs.microsoft.com/zh-CN/visualstudio/ide/build-actions

并像这样使用它:

 < PropertyGroup>< TargetFramework> netstandard2.0</TargetFramework></PropertyGroup>< ItemGroup>< Content Include ="Resources \ Image.png">< CopyToOutputDirectory> PreserveNewest</CopyToOutputDirectory></内容></ItemGroup> 

然后，您应该可以从另一个程序集中使用此Uri:

  pack://application:,,,/Resources/Image.png 

如此处所示:

https://docs.microsoft.com/zh-cn/dotnet/framework/wpf/app-development/pack-uris-in-wpf#content-file-pack-uris

但是我得到以下异常:

 引发的异常:System.Private.CoreLib.dll中的"System.Resources.MissingManifestResourceException"抛出异常:PresentationFramework.dll中的"System.IO.IOException"抛出异常:PresentationCore.dll中的"System.IO.IOException"System.Windows.Data错误:6:'TargetDefaultValueConverter'转换器无法转换值'pack://application:,,,/Resources/Image.png'(类型'String');如果可用，将使用后备值.BindingExpression:Path = BackgroundImage;DataItem ='NavigationNode'(HashCode = 663215);目标元素是'Image'(Name ='');target属性为源"(类型为"ImageSource")IOException:'System.IO.IOException:无法找到资源"resources/image.png". 

我已经清理并重建了整个解决方案.

我在做什么错了?

重要提示:我需要在xaml中使用包URI-太多，无法将所有现有代码从xaml转换为CS！

解决方案

如果引用要复制到输出目录的内容文件，则可以使用路径而不是包URI.试试这个:

  image.Source =新的BitmapImage(新的Uri($ @"{System.AppContext.BaseDirectory} \ Resources \ Image.png"，UriKind.Absolute))； 

如果出于某些原因仍需要使用包URI，请用 pack://siteoforigin:、、、 替换 pack://application:、、、 在路径中，它应该可以工作.

I want to embed a file in a .NET Standard assembly and use it in XAML in a WPF app.

If you set the build action to Resource it is very easy to use the embedded file in other assemblies, but you have to use <Project Sdk="Microsoft.NET.Sdk.WindowsDesktop"> and <UseWPF>true</UseWPF> to be able to use the Resource build action like so:

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <UseWPF>true</UseWPF>
  </PropertyGroup>

  <ItemGroup>
    <Resource Include="Resources\Image.png" />
  </ItemGroup>

Then you can use this Uri from another assembly:

pack://application:,,,/ReferencedAssembly;component/Resources/Image.png

as seen here:

https://docs.microsoft.com/en-us/dotnet/framework/wpf/app-development/pack-uris-in-wpf#resource-file-pack-uris

My question:

If you want only <Project Sdk="Microsoft.NET.Sdk"> and don't want <UseWPF>true</UseWPF> then you have to use the Content build action, because it does not require WPF, as seen here:

https://docs.microsoft.com/en-us/visualstudio/ide/build-actions

And use it like so:

  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <Content Include="Resources\Image.png">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </Content>
  </ItemGroup>

Then you should be able to use this Uri from another assembly:

pack://application:,,,/Resources/Image.png

as seen here:

https://docs.microsoft.com/en-us/dotnet/framework/wpf/app-development/pack-uris-in-wpf#content-file-pack-uris

But I get the following exception:

Exception thrown: 'System.Resources.MissingManifestResourceException' in System.Private.CoreLib.dll
Exception thrown: 'System.IO.IOException' in PresentationFramework.dll
Exception thrown: 'System.IO.IOException' in PresentationCore.dll
System.Windows.Data Error: 6 : 'TargetDefaultValueConverter' converter failed to convert value 'pack://application:,,,/Resources/Image.png' (type 'String'); fallback value will be used, if available. BindingExpression:Path=BackgroundImage; DataItem='NavigationNode' (HashCode=663215); target element is 'Image' (Name=''); target property is 'Source' (type 'ImageSource') IOException:'System.IO.IOException: Cannot locate resource 'resources/image.png'.

I have cleaned and rebuilt the whole solution.

What am I doing wrong?

Important: I need to use a pack URI in xaml - too many to convert all existing code from xaml to cs!

解决方案

If you reference a content file that gets copied to the output directory, you could use a path rather than a pack URI. Try this:

image.Source = new BitmapImage(new Uri($@"{System.AppContext.BaseDirectory}\Resources\Image.png",
    UriKind.Absolute));

If you still need to use a pack URI for some reason, replace pack://application:,,, with pack://siteoforigin:,,, in the path and it should work.

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