using System;

​

public class Program

{

    public static void Main() {

      VersionAssembly240 obj1 = new VersionAssembly240();

      VersionAssembly250 obj2 = new VersionAssembly250();

      VersionAssembly260 obj3 = new VersionAssembly260();

      ChooseRightInstance( null, obj2,  null ,  "v25" );

    }

​

    public static void ChooseRightInstance(VersionAssembly240 obj1, VersionAssembly250 obj2, VersionAssembly260 obj3, string version) 

    {

      IVersionAssembly obj;

      if (version == "v24")

      {

        obj = obj1;

      }

      else if (version == "v25")

      {

        obj = obj2;

      }

      else

      {

        obj = obj3;

      }

​

      //I need to be able to access the obj var somce the 3 classess have the same access methods

      Console.WriteLine(obj.example());

    } 

}

​

//for testing

public class VersionAssembly260 : IVersionAssembly

{

    public string example()

    {

        return "v26";

    }

}

​

public class VersionAssembly250 : IVersionAssembly

{

    public string example()

    {

        return "v25";

    }

}

​

public class VersionAssembly240 : IVersionAssembly

{

    public string example()

    {

        return "v24";

    }

}

​

public interface IVersionAssembly

{

    string example();

}