Cannot show one or more base types because the following types cannot be found: {0} Try one of the following: - Ensure that ...

Cannot show one or more base types because the following types cannot be found:

{0}
Try one of the following:
- Ensure that the base type is an existing type.
- Ensure that code model generation is complete.
- If the base type is defined outside your project, ensure you have placed the correct references in Solution Explorer.