使用AssemblyLoadContext从AssemblyPath加载后，无法在以后卸载它

huangapple
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英文:

Using AssemblyLoadContext LoadFromAssemblyPath fails to unload it later

问题

我正在在.NET 7 WPF应用程序中动态加载程序集。

此上下文加载器允许我稍后卸载它（参见 MemoryStream）：
(取自此处：https://github.com/dotnet/runtime/issues/13226)

  1. public class CollectableAssemblyLoadContext : AssemblyLoadContext
  2. {
  3.     private bool disposedValue;
  5.     public CollectableAssemblyLoadContext(string name) : base(name, true) { }
  7.     protected override Assembly Load(AssemblyName assemblyName) => null;
  9.     public Assembly Load(byte[] rawAssembly)
  10.     {
  11.         using (var memoryStream = new MemoryStream(rawAssembly))
  12.         {
  13.             var assembly = LoadFromStream(memoryStream);
  14.             return assembly;
  15.         }
  16.     }
  17. }

但是在卸载时会引发 "不可收集的程序集" 异常：
(取自此处：https://learn.microsoft.com/en-gb/dotnet/core/tutorials/creating-app-with-plugin-support)

  1. public class PluginLoader : AssemblyLoadContext
  2. {
  3.     private AssemblyDependencyResolver resolver;
  5.     public PluginLoader(string pluginPath)
  6.     {
  7.         resolver = new AssemblyDependencyResolver(pluginPath);
  8.     }
  10.     protected override Assembly Load(AssemblyName assemblyName)
  11.     {
  12.         string assemblyPath = resolver.ResolveAssemblyToPath(assemblyName);
  13.         if (assemblyPath != null)
  14.         {
  15.             return LoadFromAssemblyPath(assemblyPath);
  16.         }
  18.         return null;
  19.     }
  20. }

为什么会出现这个异常？是设计如此还是我做错了什么？

英文:

I am loading an assembly dynamically at run-time in .net 7 WPF app..

This context loader lets me to unload it later (see the MemoryStream):
(taken from here: https://github.com/dotnet/runtime/issues/13226)

  1.     public class CollectableAssemblyLoadContext : AssemblyLoadContext
  2.     {
  3.         private bool disposedValue;
  5.         public CollectableAssemblyLoadContext(string name) : base(name, true) { }
  7.         protected override Assembly Load(AssemblyName assemblyName) => null;
  9.         public Assembly Load(byte[] rawAssembly)
  10.         {
  11.             using (var memoryStream = new MemoryStream(rawAssembly))
  12.             {
  13.                 var assembly = LoadFromStream(memoryStream);
  14.                 return assembly;
  15.             }
  16.         }
  17.     }

And this throws "not collectible assembly" exception on unload:
(taken from here: https://learn.microsoft.com/en-gb/dotnet/core/tutorials/creating-app-with-plugin-support)

  1.     public class PluginLoader : AssemblyLoadContext
  2.     {
  3.         private AssemblyDependencyResolver resolver;
  5.         public PluginLoader(string pluginPath)
  6.         {
  7.             resolver = new AssemblyDependencyResolver(pluginPath);
  8.         }
  10.         protected override Assembly Load(AssemblyName assemblyName)
  11.         {
  12.             string assemblyPath = resolver.ResolveAssemblyToPath(assemblyName);
  13.             if (assemblyPath != null)
  14.             {
  15.                 return LoadFromAssemblyPath(assemblyPath);
  16.             }
  18.             return null;
  19.         }
  20.     }

Why? Is it by design or am I doing something wrong?

答案1

得分: 0

构造函数应该调用基类，并将标志设置为 true - 这确保了可收集性：

  1. public PluginLoader(string pluginPath) : base(pluginPath, true)
英文:

The constructor should call base class with flag set to true - that ensures collectability:

  1. public PluginLoader(string pluginPath) : base(pluginPath, true)

huangapple
  • 本文由 发表于 2023年7月17日 20:00:16
  • 转载请务必保留本文链接：https://go.coder-hub.com/76704244.html
  • .net-7.0
  • c#
  • plugins
  • reflection
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