Visual Studio is not recognizing new classes

If there is a solution involved, try "rebuilding" the entire solution. Rebuilding projects and websites individually didn't do it for me - after trying other suggestions here only the project rebuild worked.

Make sure it is in the same namespace as the thing you are trying to call it from, or fully declare using the namespace when creating one. Perhaps also give us an example of one that works and one that doesn't.

Also, don't forget to use the proper access modifier. Start with Public to see if that fixes your problem. If that does then your classes are almost certainly in different namespaces.

compare properties of working class with un recognised class. Specifically, "Build Action". It should resolve the problem.

if not let me know. :)