asp.net - ASP.NET Web API on .net 4.0

Question

I have ASP.NET web api project created on .NET v 4.5 I later i was decided to change framework to 4.0 After changing i got an error. VS can not regognize types and namespaces althougt all required librariesare referenced. It does not happen to newly creted test API project.

Answer 1

尝试检查您引用的 dll 是否适用于 4.0 版而不是 4.5，可能您仍在引用不适用于 .net 4 的 4.5 库。