Adding an interface to a partial class

Question

I have a class that is generated by a third party tool:

public partial class CloudDataContext : DbContext 
{
    // ...SNIPPED... 
    public DbSet<User> Users { get; set; } 

}

I create a partial class and then assign an interface so that I can inject this class later:

public partial class CloudDataContext : IDataContext
{

}   

The IDataContext has the single property Users.

This won't compile, the compiler complains that the interface isn't implemented.

If I move the interface to the generated class, it works fine. I can't do that though as it's generated code.

How can I apply an interface to a partial class to expose the class as defined above?

Answer 1

The problem must be somewhere else, because you can implement interface in the other part of partial class than it's set on. I just tried following and it compiles just fine:

public interface IFoo
{
    int Bar { get; set; }
}

public partial class Foo
{
    public int Bar { get; set; }
}

public partial class Foo : IFoo
{

}

The properties probably use different types in interface and class.

Answer 2

Here's a quick checklist. Do the classes have identical:

• Names?
• Namespaces?
• Access modifiers?

Example:

• You decide to split an existing class into two files.
• The original file's namespace doesn't match its folder path.
• Consequently, the new class file you create has a mismatching namespace.
• Build fails.