Abstract design patterns ensures that Interface is created and inside that interface all other interfaces is enclosed.

After that class will inherit that interface and makes sure which interface method is called.

1. Consider the below code, here two interfaces having the one method each i.e. DisplayBase() and DisplayTop()

interface INormal
   {
        string DisplayBase();
   }

   interface IAboveNormal
   {
       string DisplayTop();
   }

2. Here are some concrete classes which are implementing the methods of above interfaces.

public class clsWagonR : INormal
   {
       public string DisplayBase()
       {
           return "WagonR";
       }

   }

   public class clsSwift : IAboveNormal
   {
       public string DisplayTop()
       {
           return "Swift";
       }

   }

   public class clsAudiA4 : INormal
   {
       public string DisplayBase()
       {
           return "Audi A4";
       }

   }

   public class clsAudiQ7 : IAboveNormal
   {
       public string DisplayTop()
       {
           return "Audi Q7";
       }

   }

3. Now, We will create the abstract factory patter. In below code there is an interface which clubs the above interface i.e. INormal and IAboveNormal. Also see the classes which are implementing this interface.

interface Icar
{
    INormal GetNormal();
    IAboveNormal GetAboveNormal();
}

class clsMaruti : Icar
{
    public INormal GetNormal()
    {
        return new clsWagonR();
    }

    public IAboveNormal GetAboveNormal()
    {
        return new clsSwift();
    }
}

class clsAudi : Icar
{
    public INormal GetNormal()
    {
        return new clsAudiA4();
    }

    public IAboveNormal GetAboveNormal()
    {
        return new clsAudiQ7();
    }
}

4. Next, the class which you can see below contains the method which decides whose object should be now created (you can put this method in client code instead of making new class).

class clsDecider
    {
        public string GetCarDetails(int iCarType)
        {
            Icar ObjClient=null;
            switch (iCarType)
            {
                case 1:
                    ObjClient = new clsMaruti();
                    break;
                case 2:
                     ObjClient = new clsAudi();
                    break;
                default:
                    ObjClient = new clsMaruti();
                    break;
            }

            string sOutput = "Normal Car is: "+ ObjClient.GetNormal().DisplayBase()+", Above Normal car is: "+ ObjClient.GetAboveNormal().DisplayTop();
            return sOutput;
        }
    }

5. Finally, Below is my client code:

clsDecider ObjDecider = new clsDecider();
string sResult= ObjDecider.GetCarDetails(2);