I have the following base interface

public interface IHandler{
  void Handle(IMessage message);
}

and an generic interface inheriting the base interface

public interface IHandler<TMessage> : IHandler where TMessage : IMessage{
  void Handle(TMessage message);
}

My classes can implement the interface IHandler<TMessage> mutiple times. IMessage is an base interface for messages and isn´t relevant here. Currently i´m implementing the interfaces as follows.

public class ExampleHandler : IHandler<ExampleMessage>, IHandler<OtherExampleMessag>{

  void IHandler.Handle(IMessage message){
    ExampleMessage example = message as ExampleMessage;

    if (example != null) {
      Handle(example);
    }
    else {
      OtherExampleMessage otherExample = message as OtherExampleMessage;

      if (otherExample != null) {
        Handle(otherExample);
      }
  }

  public void Handle(ExampleMessage) {
   //handle message;
  }

  public void Handle(OtherExampleMessage) {
   //handle message;
  }
}

What bothers me is the way i have to implement the Handle(IMessage) method, cause in my opinion its many redundant code, and i have to extend the method each time when i implement a new IHandler<TMessage> interface on my class.

What i´m looking for is a more generic way to implement the Handle(IMessage) method (maybe in a base class for Handlers), but i´m currently stuck how to do that.