Interface inheritance

Question

Hi I have two interface classes for two view models for example I have interface IbaseA and IbaseB. IbaseB have same interfaces as IbaseB and some extra interfaces.IbaseA class interface is implemented in Aviewmodel and IbaseB class interface is implemented in Bviewmodel.These view models bind to different user control.I want to remove duplicate code means interfaces and properties.So plz help me to find out the best way to do it with same example if possible. Thanks Sneha

Gaurav Gahlot · Answer

Hi Sneha I think you can have a base implementation class say ViewModelBase  which contains the implementation of common methods. Your two other view models shall now inherit from this base class so that the common implementation is available to both. In case your ViewModelBase has some dependencies you may pass them using your child view models as shown below: public class ViewModelBase { private readonly InterfaceOne _interfaceOne; private readonly InterfaceTwo _interfaceTwo; public ViewModelBase(InterfaceOne interfaceOne InterfaceTwo interfaceTwo) { _interfaceOne = interfaceTwo; _interfaceTwo = interfaceTwo; } // implementation of common methods } public class AViewModel { private readonly InterfaceOne _interfaceOne; private readonly InterfaceTwo _interfaceTwo; public AViewModel(InterfaceOne interfaceOne InterfaceTwo interfaceTwo) : base (interfaceOne interfaceTwo) { _interfaceOne = interfaceTwo; _interfaceTwo = interfaceTwo; } // implementation of methods specific to this view model } public class BViewModel { private readonly InterfaceOne _interfaceOne; private readonly InterfaceTwo _interfaceTwo; public BViewModel(InterfaceOne interfaceOne InterfaceTwo interfaceTwo) : base (interfaceOne interfaceTwo) { _interfaceOne = interfaceTwo; _interfaceTwo = interfaceTwo; } // implementation of methods specific to this view model } I hope this helps solving your problem. However it would have been quite helpful if you could have included some snippet supporting your question for better clarity. Thank you!