In a specific project (meant for web-services) in my .net solution (Visual Studio), I have added a using directive:
using ourSystem.Common.WPF
and I also added the corresponding reference (pointing to the DLL) to the project file.
The web-services project compiles, builds, and works just fine until I try to add the WPF project.
When I add the WPF project, I get the error message:
Error CS0234 The type or namespace name 'WPF' does not exist in the namespace 'ourSystem.Common' (are you missing an assembly reference?)
I have looked at similar questions on stack overflow and web posts elsewhere, but nothing seems to work.
It appears that the problem must be some sort of incompatibility between files.
NOTE: The Visual Studio Solution (VS2019) I am working on has several projects, and this DLL/namespace works in many of the other projects, just not the project that I am trying to add it to.
Both the WPF project and the project I am trying to reference it in are v4.5.2 Thus, at least for that attribute, they should be compatible.
For what it's worth, I have also tried unloading projects, and reloading them. This often changes the error count from about 4 (all the same message) to well over 100, and it seems to lose all references to everything.
Edit added: It turns out the relative structure of the many projects within the solution (which I didn't describe in the original post of this question) was key in finding an answer. See my own answer below for details, if interested.
Any suggestions on how to fix this problem?
CodePudding user response：
I was able to fix it essentially as follows:
I refactored the directory structure.
It had been A-> Top Level GUI project that had called B & C
B-> Folder with the projects used by A including WPF, but not Web Service Project.
C-> Folder with Web Service Project
I then moved all of C to the same layer as B. Having them in the same folder seemed to 'placate' the compiler.
I am not claiming that this was absolutely needed, nor that it should always be done, however it worked in my case.
I had to also redo some code within the C project to account for different layering within C's own folders (especially packages folder), as it still had legacy code as if it were the top-level project. The following link was useful in that: (especially the answer by Nikita R.)