使用AssemblyLoadContext处理程序集与调用应用的同依赖多版本冲突问题

API 探路者

2026-6-23

多版本依赖加载问题排查与解决方案

问题场景

有一个包含三个项目的解决方案：

控制台应用Runner，依赖RestWrapper v3.0.19；
类库Module1，依赖RestWrapper v3.0.20；
类库Module2，依赖RestWrapper v3.0.18。

三者均需对Runner获取的用户指定URL执行HTTP GET请求。Runner尝试通过AssemblyLoadContext、LoadFromAssemblyPath、Resolving事件及Activator.CreateInstance创建并调用Module1和Module2中的Process方法，但运行Module1时触发System.IO.FileLoadException，提示无法加载RestWrapper v3.0.20。

已做配置与确认

已确认Module1和Module2的输出文件（含依赖）已复制到Runner对应目录的module1/和module2/子目录；

Module1和Module2的.csproj中已配置：

<CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
<PublishSingleFile>true</PublishSingleFile>
<SelfContained>true</SelfContained>

核心代码片段

模块实例化代码

AssemblyLoadContext ctx1 = new AssemblyLoadContext("module1", false);
Assembly asm1 = ctx1.LoadFromAssemblyPath(Path.GetFullPath("module1/Module1.dll"));

ctx1.Resolving += (ctx, assemblyName) =>
{
    Console.WriteLine("| Module 1 loading assembly " + assemblyName.FullName);
    var parts = assemblyName.FullName.Split(',');
    string name = parts[0];
    var version = Version.Parse(parts[1].Split('=')[1]);
    string filename = new FileInfo(Path.GetFullPath("module1/" + name + ".dll")).FullName;
    Console.WriteLine("| Module 1 loading from file " + filename);

    Assembly asm = Assembly.LoadFrom(filename);
    Console.WriteLine("| Module 1 loaded assembly " + filename);
    return asm;
};

Type type1 = asm1.GetType("Module1.Processor", true);
dynamic instance1 = Activator.CreateInstance(type1);
instance1.Process(url);

REST请求代码

using (RestRequest req = new RestRequest(url))
{
    using (RestResponse resp = req.Send())
    {
        Console.WriteLine("| Status (runner) : " + resp.StatusCode + " " + resp.ContentLength + " bytes");
    }
}

错误输出

C:\Code\Misc\DependencyExample\Runner\bin\Debug\net8.0>runner

URL: https://www.google.com
| Status (runner) : 200 57841 bytes
| Module 1 loading assembly RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null
| Module 1 loading from file C:\Code\Misc\DependencyExample\Runner\bin\Debug\net8.0\module1\RestWrapper.dll
System.IO.FileLoadException: Could not load file or assembly 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'. Could not find or load a specific file. (0x80131621)
File name: 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'
 ---&gt; System.IO.FileLoadException: Could not load file or assembly 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'.
   at System.Runtime.Loader.AssemblyLoadContext.LoadFromAssemblyPath(String assemblyPath)
   at System.Reflection.Assembly.LoadFrom(String assemblyFile)
   at DependencyExample.Program.&lt;&gt;c.&lt;Main&gt;b__0_0(AssemblyLoadContext ctx, AssemblyName assemblyName) in C:\Code\Misc\DependencyExample\Runner\Program.cs:line 49
   at System.Runtime.Loader.AssemblyLoadContext.GetFirstResolvedAssemblyFromResolvingEvent(AssemblyName assemblyName)
   at System.Runtime.Loader.AssemblyLoadContext.ResolveUsingEvent(AssemblyName assemblyName)
   at System.Runtime.Loader.AssemblyLoadContext.ResolveUsingResolvingEvent(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)
   at Module1.Processor.Process(String url)
   at System.Dynamic.UpdateDelegates.UpdateAndExecuteVoid2[T0,T1](CallSite site, T0 arg0, T1 arg1)
   at DependencyExample.Program.Main(String[] args) in C:\Code\Misc\DependencyExample\Runner\Program.cs:line 56

补充尝试

使用AssemblyDependencyResolver后可运行，但Runner、Module1、Module2均加载同一版本RestWrapper，未实现各自版本隔离；
完整代码如下：

Runner的Program.cs

namespace DependencyExample
{
    using RestWrapper;
    using System;
    using System.IO;
    using System.Reflection;
    using System.Runtime.Loader;

    internal class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                Console.Write(Environment.NewLine + "URL: ");
                string url = Console.ReadLine();
                if (String.IsNullOrEmpty(url)) continue;

                try
                {
                    #region Local

                    using (RestRequest req = new RestRequest(url))
                    {
                        using (RestResponse resp = req.Send())
                        {
                            Console.WriteLine("| Status (runner) : " + resp.StatusCode + " " + resp.ContentLength + " bytes");
                        }
                    }

                    #endregion

                    #region Module1

                    PluginLoadContext ctx1 = new PluginLoadContext("module1/");
                    Assembly asm1 = ctx1.LoadFromAssemblyPath(Path.GetFullPath("module1/Module1.dll"));

                    ctx1.Resolving += (ctx, assemblyName) =>
                    {
                        Console.WriteLine("| Module 1 loading assembly " + assemblyName.FullName);
                        var parts = assemblyName.FullName.Split(',');
                        string name = parts[0];
                        var version = Version.Parse(parts[1].Split('=')[1]);
                        string filename = new FileInfo(Path.GetFullPath("module1/" + name + ".dll")).FullName;
                        Console.WriteLine("| Module 1 loading from file " + filename);

                        Assembly asm = Assembly.LoadFrom(filename);
                        Console.WriteLine("| Module 1 loaded assembly " + filename);
                        return asm;
                    };

                    Type type1 = asm1.GetType("Module1.Processor", true);
                    dynamic instance1 = Activator.CreateInstance(type1);
                    instance1.Process(url);

                    #endregion

                    #region Module2

                    PluginLoadContext ctx2 = new PluginLoadContext("module2/");
                    Assembly asm2 = ctx2.LoadFromAssemblyPath(Path.GetFullPath("module2/Module2.dll"));

                    ctx1.Resolving += (ctx, assemblyName) =>
                    {
                        Console.WriteLine("| Module 2 loading assembly " + assemblyName.FullName);
                        var parts = assemblyName.FullName.Split(',');
                        string name = parts[0];
                        var version = Version.Parse(parts[1].Split('=')[1]);
                        string filename = new FileInfo(Path.GetFullPath("module2/" + name + ".dll")).FullName;
                        Console.WriteLine("| Module 2 loading from file " + filename);

                        Assembly asm = Assembly.LoadFrom(filename);
                        Console.WriteLine("| Module 2 loaded assembly " + filename);
                        return asm;
                    };

                    Type type2 = asm2.GetType("Module2.Processor", true);
                    dynamic instance2 = Activator.CreateInstance(type2);
                    instance2.Process(url);

                    #endregion

                    Console.WriteLine("Finished URL " + url);
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.ToString());
                }
            }
        }
        private class PluginLoadContext : AssemblyLoadContext
        {
            private AssemblyDependencyResolver _Resolver;

            public PluginLoadContext(string baseDirectory)
            {
                _Resolver = new AssemblyDependencyResolver(Path.GetFullPath(baseDirectory));
            }

            protected override Assembly? Load(AssemblyName name)
            {
                Console.WriteLine("  | Loading assembly: " + name);
                string path = _Resolver.ResolveAssemblyToPath(name);
                if (path != null)
                {
                    return LoadFromAssemblyPath(path);
                }
                return null;
            }

            protected override IntPtr LoadUnmanagedDll(string name)
            {
                Console.WriteLine("  | Loading unmanaged assembly: " + name);
                string path = _Resolver.ResolveUnmanagedDllToPath(name);
                if (path != null)
                {
                    return LoadUnmanagedDllFromPath(path);
                }
                return IntPtr.Zero;
            }
        }
    }
}

Module1的Processor.cs

namespace Module1
{
    using RestWrapper;
    using System;

    public class Processor
    {
        public Processor()
        {

        }

        public void Process(string url)
        {
            using (RestRequest req = new RestRequest(url))
            {
                using (RestResponse resp = req.Send())
                {
                    Console.WriteLine("| Status (module1): " + resp.StatusCode + " " + resp.ContentLength + " bytes");
                }
            }
        }
    }
}

Module2的Processor.cs

namespace Module2
{
    using RestWrapper;
    using System;

    public class Processor
    {
        public Processor()
        {

        }

        public void Process(string url)
        {
            using (RestRequest req = new RestRequest(url))
            {
                using (RestResponse resp = req.Send())
                {
                    Console.WriteLine("| Status (module2): " + resp.StatusCode + " " + resp.ContentLength + " bytes");
                }
            }
        }
    }
}

解决方案

问题根源

Assembly.LoadFrom的陷阱：在Resolving事件中使用Assembly.LoadFrom会将程序集加载到默认加载上下文，而非当前的PluginLoadContext，导致版本冲突（默认上下文已加载了Runner的v3.0.19，无法再加载v3.0.20）；
Module2的事件绑定错误：代码中将Module2的Resolving事件绑定到了ctx1而非ctx2，导致Module2的依赖会错误地从Module1目录加载；
PluginLoadContext的Load方法优先级：自定义Load方法会先于Resolving事件触发，而当前实现中AssemblyDependencyResolver可能会错误地从全局路径加载依赖，而非模块目录。

修复步骤

1. 替换`Assembly.LoadFrom`为当前上下文的`LoadFromAssemblyPath`

在Resolving事件中，必须使用当前AssemblyLoadContext的LoadFromAssemblyPath方法，确保程序集加载到对应上下文：

ctx1.Resolving += (ctx, assemblyName) =>
{
    Console.WriteLine("| Module 1 loading assembly " + assemblyName.FullName);
    var parts = assemblyName.FullName.Split(',');
    string name = parts[0];
    string filename = Path.GetFullPath($"module1/{name}.dll");
    Console.WriteLine("| Module 1 loading from file " + filename);

    // 关键：使用当前上下文的LoadFromAssemblyPath，而非Assembly.LoadFrom
    Assembly asm = ctx.LoadFromAssemblyPath(filename);
    Console.WriteLine("| Module 1 loaded assembly " + filename);
    return asm;
};

2. 修正Module2的事件绑定

将Module2的Resolving事件绑定到ctx2，而非ctx1：

// 原错误代码：ctx1.Resolving += ...
ctx2.Resolving += (ctx, assemblyName) =>
{
    Console.WriteLine("| Module 2 loading assembly " + assemblyName.FullName);
    var parts = assemblyName.FullName.Split(',');
    string name = parts[0];
    string filename = Path.GetFullPath($"module2/{name}.dll");
    Console.WriteLine("| Module 2 loading from file " + filename);

    Assembly asm = ctx.LoadFromAssemblyPath(filename);
    Console.WriteLine("| Module 2 loaded assembly " + filename);
    return asm;
};

3. 调整`PluginLoadContext`的`Load`方法，确保模块优先加载自身目录依赖

修改Load方法，避免AssemblyDependencyResolver错误加载全局版本：

protected override Assembly? Load(AssemblyName name)
{
    Console.WriteLine("  | Loading assembly: " + name);
    // 优先从模块目录加载，而非依赖解析器的全局查找
    string modulePath = Path.Combine(_Resolver.BaseDirectory, $"{name.Name}.dll");
    if (File.Exists(modulePath))
    {
        return LoadFromAssemblyPath(modulePath);
    }
    // 再尝试依赖解析器
    string path = _Resolver.ResolveAssemblyToPath(name);
    if (path != null)
    {
        return LoadFromAssemblyPath(path);
    }
    return null;
}

4. 移除`PublishSingleFile`配置（调试阶段）

PublishSingleFile会将所有依赖打包到单个文件，导致模块的依赖无法独立存在于子目录，调试阶段建议禁用：

<!-- 移除或注释该行 -->
<!-- <PublishSingleFile>true</PublishSingleFile> -->

验证效果

修复后，每个模块的RestWrapper会加载对应目录的版本，控制台输出应显示：

URL: https://www.google.com
| Status (runner) : 200 57841 bytes
| Module 1 loading assembly RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null
| Module 1 loading from file .../module1/RestWrapper.dll
| Module 1 loaded assembly .../module1/RestWrapper.dll
| Status (module1): 200 57841 bytes
| Module 2 loading assembly RestWrapper, Version=3.0.18.0, Culture=neutral, PublicKeyToken=null
| Module 2 loading from file .../module2/RestWrapper.dll
| Module 2 loaded assembly .../module2/RestWrapper.dll
| Status (module2): 200 57841 bytes
Finished URL https://www.google.com

内容的提问来源于stack exchange，提问作者joelc

使用AssemblyLoadContext处理程序集与调用应用的同依赖多版本冲突问题

问题场景 #

已做配置与确认 #

核心代码片段 #

模块实例化代码 #

REST请求代码 #

错误输出 #

补充尝试 #

Runner的Program.cs #

Module1的Processor.cs #

Module2的Processor.cs #

解决方案 #

问题根源 #

修复步骤 #

1. 替换Assembly.LoadFrom为当前上下文的LoadFromAssemblyPath