[Guid("14B55D90-E07B-4DC9-B2EE-25F15607518B")]
[ComVisible(true)]
public interface ComInterface
{
    [DispId(0)]
    void ShowWindow();
}

[Guid("CC01974D-82E2-4E9E-A48C-562D3ED83459")]
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
[ComDefaultInterface(typeof(ComInterface))]

public class ComClass: ComInterface
{
    public void ShowWindow()
    {
        MainWPFWindow window = new MainWPFWindow();
        window.Show();
    }
}