您先前的问题已经解决了这个问题.
错误消息中存在的所有方法和/或名称都必须由编译器通过您的代码中的定义或通过引用程序集和名称空间来访问.

干杯

Your previous question already covered the problem.
All the methods and/or names present in the error messages need to be reachable by the compiler either through definition in your code or by reference to the assembly and namespace.

Cheers