System.Runtime.CompilerServices.Unsafe 在 Xamarin Forms 中产生意外行为

Question

我构建了一个完整的 Xamarin From 应用程序。当我将构建模式更改为 Release 时，我收到此错误消息：

Severity Code Description Project File Line Suppression State Error The "LinkAssemblies" task failed unexpectedly. Mono.Linker.MarkException: Error processing method: 'System.Void Microsoft.Extensions.Primitives.InplaceStringBuilder::Append(System.String,System.Int32,System.Int32)' in assembly: 'Microsoft.Extensions.Primitives.dll' ---> Mono.Cecil.ResolutionException: Failed to resolve System.Void System.Runtime.CompilerServices.Unsafe::CopyBlockUnaligned(System.Void*,System.Void*,System.UInt32) at Mono.Linker.Steps.MarkStep.HandleUnresolvedMethod(MethodReference reference) at Mono.Linker.Steps.MarkStep.MarkMethod(MethodReference reference) at Mono.Linker.Steps.MarkStep.MarkInstruction(Instruction instruction)
at Mono.Linker.Steps.MarkStep.MarkMethodBody(MethodBody body) at Mono.Linker.Steps.MarkStep.ProcessMethod(MethodDefinition method)
at Mono.Linker.Steps.MarkStep.ProcessQueue() --- End of inner exception stack trace --- at Mono.Linker.Steps.MarkStep.ProcessQueue() at Mono.Linker.Steps.MarkStep.ProcessEntireQueue() at Mono.Linker.Steps.MarkStep.Process() at Mono.Linker.Steps.MarkStep.Process(LinkContext context) at Mono.Linker.Pipeline.Process(LinkContext context) at MonoDroid.Tuner.Linker.Process(LinkerOptions options, LinkContext& context) at Xamarin.Android.Tasks.LinkAssemblies.Execute(DirectoryAssemblyResolver res) at Xamarin.Android.Tasks.LinkAssemblies.Execute() at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute() at Microsoft.Build.BackEnd.TaskBuilder.d__26.MoveNext() EClinicForDoctor.Android

在网上搜索后，我发现这个 solution 上面写着：

此问题的解决方法是确保您拥有支持的最新 Android SDK 版本，并将目标框架设置为使用最新安装的平台。还建议您将目标 Android 版本设置为使用目标框架版本，并将最低 Android 版本设置为 API 15 或更高版本。这被认为是受支持的配置。

因此我更新 Android SDK，设置目标框架并将最低 Android 版本设置为 API 15。

但是，我仍然遇到同样的错误。另一个解决方案说我应该更新 NuGet Packages。我发现包 System.Runtime.CompilerServices.Unsafe 的版本是 4.3.0 并且有针对这个包的更新。更新包时，错误不再出现，但出现另一个问题。当应用程序部署时，它运行并在没有任何错误消息的情况下停止。手机只是退出应用程序而不显示任何错误消息。当软件包 System.Runtime.CompilerServices.Unsafe 的版本高于 4.3.0 时会发生这种情况。我试图删除包，同样的问题再次发生。我该如何解决这个问题？

Answer 1

我现在已经在几个不同的位置看到了这个问题弹出窗口。围绕它进行了一些讨论，如下所示：https://github.com/xamarin/xamarin-android/issues/1196

这个 Github 问题还列出了一些（可能的）解决方案，反馈最积极的似乎是这个：

Here's a functioning workaround. It's hacky and ugly but works with minimum fuss. Put this in an XML file and <Import> it in your Android csproj file at the end. It works at least for System.Buffers

<!-- Workaround for https://github.com/xamarin/xamarin-android/issues/1162 -->
<Project>
  <Target Name="ReplaceRefAssemblies" AfterTargets="_ResolveAssemblies">
    <ItemGroup>
      <ResolvedAssembliesFixedWindows Include="@(ResolvedAssemblies->Replace('\ref\','\lib\'))" />
      <ResolvedAssembliesFixedUnix Include="@(ResolvedAssemblies->Replace('/ref/','/lib/'))" />
      <ResolvedAssembliesFixed Include="@(ResolvedAssembliesFixedWindows)" Condition="@(ResolvedAssembliesFixedWindows) != @(ResolvedAssemblies)" />
      <ResolvedAssembliesFixed Include="@(ResolvedAssembliesFixedUnix)" Condition="@(ResolvedAssembliesFixedUnix) != @(ResolvedAssemblies)" />
      <ResolvedAssemblies Remove="@(ResolvedAssemblies)" />
      <ResolvedAssemblies Include="@(ResolvedAssembliesFixed)" />
    </ItemGroup>
  </Target>
</Project>

另一个使用上面的 XML 并说：

I've just copied the content from the link above and saved as UnsafeFix.xml file in the Android project folder.

Then just added: <Import Project="UnsafeFix.xml" /> at the end of android .csproj file, just before

Cleared everything, recompiled and it finally worked!

Answer 2

终于找到解决办法了。 @Gerald Versluis 提供的 issue 中的评论之一解决了问题：

I follow these steps of hongliyu2002 https://forums.realm.io/t/could-not-load-assembly-system-runtime-compilerservices-unsafe-during-startup-registration/974/4

Go to C:\Users%user%.nuget\system.runtime.compilerservices.unsafe.4.0, and delete "ref" folder then make a copy of "lib" folder and rename the copy back to "ref".

Cleanup all the "bin" and "obj" folders in the projects.

Rebuild and run..

This simple workaround , works for me :) My current version is Xamarin.Forms 2.5.1.444934

System.Runtime.CompilerServices.Unsafe 在 Xamarin Forms 中产生意外行为

System.Runtime.CompilerServices.Unsafe produce unexpected behavior in Xamarin Forms

c#

android

release

xamarin.forms