Namespace in Referenced Project Present in Autocomplete Before Building, but Causes Compile Error After Building

Question

Hi,

I have a class library project which uses a namespace (e.g., "Cosmos.Creator.Util"). I then create a solution and windows forms application to test the library. From the windows form application, I add a reference to the library. So now I have two projects open in visual studio, a class library and a windows forms project. The forms project references the library.

When I edit my form's code, code autocompletion works correctly for the namespace that I use in the library. E.g., if I type "using Cosmos." I get autocomplete options like "Creator". But now if I build my solution, all of the "Cosmos" are red-underlined with the compile error: "The type or namespace name "Cosmos" could not be found (are you missing a using directive or an assembly reference?)".

For the purposes of the form application test, I placed my library code into a folder CosmosFormExample\Cosmos. When I check the reference from the form application, the reference is to CosmosFormExample\Cosmos\bin\Debug\Cosmos.dll, so that looks okay. I looked at the GUID referenced in the solution file and it matches the GUID of the project file Cosmos.csproj.

What has happened? How has the build caused my forms application to forget about the Cosmos namespace, despite the fact that it is still referencing the library project? Thanks much in advance.

Answer 1

Are you using VS2010 & .NET 4? If so you're probably using .NET 4 Client Profile instead of full fledged .NET 4. Go to project properties and check your Target Framework.

for more info: http://msdn.microsoft.com/en-us/library/cc656912.aspx

Answer 2

you need to check the framework you are using and the framework yout library was compiled for...