某些类可能会出现.net 3.5之前没有的错误：

　　错误 3 无法嵌入互操作类型“ESRI.ArcGIS.DataSourcesGDB.FileGDBWorkspaceFactoryClass”。请改用适用的接口。 

解决方案：

    2) The reason you could not compile against .NET 4.0 is because the "Embed Interop Types" property was set to true on the ESRI assembly references. If you change "Embed Interop Types" to false for all the ESRI references in the project, it will build against .NET 4.0.

.net4.0 框架使用ArcEngine