Implementing multiple interface using generics

Question

I want to implement the methods in interface using generics. But I am getting error. eg //Filter is a class here.

public interface IComponent<T>
{
  List<T> GetOrderSummary(Filter input);
  T GetOrderDetails(string orderId);
  List<T> GetOrderSummaryDetails(Filter input);
}

// ORDER A AND ORDER B ARE TWO MODEL CLASSES HERE
public class OrderDetails : IComponent<OrderA>,IComponent<OrderB>
{
  public List<OrderA> GetOrderSummary(Filter input)
  {
    //Some logic
    //lst of type OrderA
    return lst;
  }

  public List<OrderB> GetOrderSummaryDetails(Filter input)
  {
    //Some logic
    //lst of type OrderB
    return lst
  }

  public OrderA GetOrderDetails(string orderId)
  {
    throw new NotImplementedException();
  }
}

I am getting error building that

OrderDetails does not implement interface member IComponent.GetOrderSummaryDetails(Filter).OrderDetails.GetOrderSummaryDetails cannot implement IComponent.GetOrderSummaryDetails(Filter) beacuse it does not have the matching return type of List<OrderA>

OrderDetails does not implement interface member IComponent.GetOrderSummary(Filter).OrderDetails.GetOrderSummary cannot implement IComponent.GetOrderSummary(Filter) beacuse it does not have the matching return type of List<OrderB>

OrderDetails does not implement interface member IComponent.GetOrderDetails(string).OrderDetails.GetOrderDetails(string) cannot implement IComponent.GetOrderDetails(string) beacause it does not have the matching return type OrderB

Please let me know how to fix these issues.

Answer 1

You need explicit implementation of both interfaces, like this:

public class OrderDetails : IComponent<OrderA>, IComponent<OrderB>
{
    List<OrderA> IComponent<OrderA>.GetOrderSummary(Filter input)
    {
        throw new NotImplementedException();
    }

    OrderB IComponent<OrderB>.GetOrderDetails(string orderId)
    {
        throw new NotImplementedException();
    }

    List<OrderB> IComponent<OrderB>.GetOrderSummaryDetails(Filter input)
    {
        throw new NotImplementedException();
    }

    List<OrderB> IComponent<OrderB>.GetOrderSummary(Filter input)
    {
        throw new NotImplementedException();
    }

    OrderA IComponent<OrderA>.GetOrderDetails(string orderId)
    {
        throw new NotImplementedException();
    }

    List<OrderA> IComponent<OrderA>.GetOrderSummaryDetails(Filter input)
    {
        throw new NotImplementedException();
    }
}

Later, to access proper method you can use either casting or proper variable type:

var orderDetails1 = new OrderDetails();
var details1 = ((IComponent<OrderA>)orderDetails1).GetOrderDetails("");

IComponent<OrderA> orderDetails2 = new OrderDetails();
var details2 = orderDetails2.GetOrderDetails("");