c# - 在全局名称空间中找不到类型或名称空间名称“名称空间”（您是否缺少程序集引用？）

[英]The type or namespace name '“Namespace”' could not be found in the global namespace (are you missing an assembly reference?)

[英]I'm getting error “The type or namespace name 'CS' could not be found in the global namespace (are you missing an assembly reference?)”

[英]The type or namespace 'system' could not be found. Are you missing an assembly reference?

[英]Error "The type or namespace 'MyType' could not be found (or are you missing an assembly reference?)"

[英]Type or namespace name could not be found (missing using directive or assembly reference?)

[英]The type or namespace name 'My_Interface_Name' could not be found (are you missing a using directive or an assembly reference?)

[英]The type or namespace name does not exist in the namespace ''are you missing an assembly reference ?"

[英]The type or namespace name does not exist in the namespace (are you missing an assembly reference?)

[英]The type or namespace name 'FacebookSessionClient' could not be found (are you missing a using directive or an assembly reference?)

[英]The type or namespace name 'SignInManager' could not be found (are you missing a using directive or an assembly reference?)

在全局名称空间中找不到类型或名称空间名称“名称空间”（您是否缺少程序集引用？）