I had the same problem. I figured out that my assembly, which is loaded by the main program, had some references with "Copy Local" set to true. These local copies of references were looking for other references in the same folder, which did not exist because the "Copy Local" of other references was set to false. After the deletion of the "accidentally" copied references the error was gone because the main program was set to look for correct locations of references. Apparently the local copies of the references screwed up the sequence of calling because these local copies were used instead of the original ones present in the main program.

重要的信息是，出现此错误是因为缺少加载所需程序集的链接。

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简短的回答

如果将方法添加到一个程序集中的接口，然后再添加到另一个程序集中的实现类，但在没有引用接口程序集中的新版本的情况下重新构建实现程序集中，就会发生这种情况。

在本例中，DummyItem实现了来自另一个程序集的接口。SetShort方法最近被添加到接口和DummyItem中—但是包含DummyItem的程序集是引用先前版本的接口程序集重新构建的。因此SetShort方法有效地存在，但没有将其链接到接口中的等效方法。

长回答

如果你想尝试复制这个，试试下面的方法:

Create a class library project: InterfaceDef, add just one class, and build: public interface IInterface { string GetString(string key); //short GetShort(string key); } Create a second class library project: Implementation (with separate solution), copy InterfaceDef.dll into project directory and add as file reference, add just one class, and build: public class ImplementingClass : IInterface { #region IInterface Members public string GetString(string key) { return "hello world"; } //public short GetShort(string key) //{ // return 1; //} #endregion } Create a third, console project: ClientCode, copy the two dlls into the project directory, add file references, and add the following code into the Main method: IInterface test = new ImplementingClass(); string s = test.GetString("dummykey"); Console.WriteLine(s); Console.ReadKey(); Run the code once, the console says "hello world" Uncomment the code in the two dll projects and rebuild - copy the two dlls back into the ClientCode project, rebuild and try running again. TypeLoadException occurs when trying to instantiate the ImplementingClass.

I had the same problem. I figured out that my assembly, which is loaded by the main program, had some references with "Copy Local" set to true. These local copies of references were looking for other references in the same folder, which did not exist because the "Copy Local" of other references was set to false. After the deletion of the "accidentally" copied references the error was gone because the main program was set to look for correct locations of references. Apparently the local copies of the references screwed up the sequence of calling because these local copies were used instead of the original ones present in the main program.

重要的信息是，出现此错误是因为缺少加载所需程序集的链接。

我也有这个错误，这是由任何CPU exe引用的任何CPU程序集，反过来引用x86程序集引起的。

异常抱怨MyApp中类的一个方法。实现(任何CPU)，它派生了MyApp。接口(任何CPU)，但在fuslogvw.exe中，我发现了一个隐藏的“试图从MyApp加载格式不正确的程序”异常。CommonTypes (x86)，两者都使用它。

我在重命名一个由ASP依赖的项目(和程序集名称)时遇到了这个问题。网络项目。类型在依赖程序集中实现了接口。尽管从“生成”菜单执行“清洁解决方案”，但具有先前名称的程序集仍保留在bin文件夹中，并且当我的web项目执行时

var types = AppDomain.CurrentDomain.
   GetAssemblies().
   ToList().
   SelectMany( s => s.GetTypes() /* exception thrown in this call */ )
;

上面的异常被抛出，抱怨实现web类型中的接口方法实际上没有实现。手动删除web项目的bin文件夹中的程序集解决了这个问题。

这仅仅意味着实现项目在我的案例中已经过时了。重新构建了包含接口的DLL，但实现DLL陈旧。