关于 .NET AssemblyLoadContext 的研究笔记
public class MyAssemblyLoadContext : AssemblyLoadContext{private readonly AssemblyDependencyResolver _resolver;public MyAssemblyLoadContext(string pluginDllPath) : base(isCollectible: true){// 传入的是“主程序集”路径，resolver 会自动找同名的 .deps.json_resolver = new AssemblyDependencyResolver(pluginDllPath);}// 2. 只要插件里出现“using xxx;”，运行时就会走到这里protected override Assembly? Load(AssemblyName name){string? path = _resolver.ResolveAssemblyToPath(name);if (path != null) return LoadFromAssemblyPath(path);return null; // 返回 null 会让运行时继续默认逻辑}// 3. 非托管 dll (sqlite、libuv …) 同理protected override IntPtr LoadUnmanagedDll(string unmanagedName){string? path = _resolver.ResolveUnmanagedDllToPath(unmanagedName);return path != null ? LoadUnmanagedDllFromPath(path) : IntPtr.Zero;}}
internal class Program{private static AssemblyLoadContext _alc;static void ALCLoadLib1(){ALCUnload();var file = @"G:\fanbalcode\testwebswagger\ALCHost\Lib1\bin\Debug\net8.0\publish\Lib1.dll";var myALC = new MyAssemblyLoadContext(file);myALC.LoadFromAssemblyPath(file);_alc = myALC;}static void ALCLoadLib2(){ALCUnload();var file = @"G:\fanbalcode\testwebswagger\ALCHost\Lib2\bin\Debug\net8.0\publish\Lib2.dll";var myALC = new MyAssemblyLoadContext(file);myALC.LoadFromAssemblyPath(file);_alc = myALC;}static void ALCUnload(){if (_alc is not null) _alc.Unload();}private static WeakReference GetStudent(){var studentType = _alc.Assemblies.Select(i => i.GetType("Lib.Student")).FirstOrDefault(i => i is not null);var studentIns = Activator.CreateInstance(studentType);return new WeakReference(studentIns);}static void Main(string[] args){ALCLoadLib1();var student1 = GetStudent();ALCLoadLib2();var student2 = GetStudent();Console.WriteLine(student2);// 2. 持续 GC 直到确认释放for (int i = 0; i < 10 && student1.IsAlive; i++){GC.Collect();GC.WaitForPendingFinalizers();Console.WriteLine($"GC #{i + 1}: " + student1.IsAlive);}}}
通过 AssemblyLoadContext 可以实现可卸载的插件系统，对于游戏的热更新或者一些强调扩展性的软件开发有着重要的意义。
