This seems like a reasonable (and maybe simple?) scenario, but how would you do the following:
Lets say I have 2 interfaces:
Interface ISimpleInterfa
Sorry but I don't master VB.Net syntax.
In C# you can implement interfaces implicitly or explicitly. If your class Foo implements ErrorMsg as a public method, this implementation will be used for both interface.
If you want distinct implementation you can implement it explicitly :
string ISimpleInterface.ErrorMsg {get { ... } }
string IExtendedInterface.ErrorMsg {get { ... } set { ... }}