How to create a derived class from a class in a class librar

Sure, C# will support that. Take a look at this example that uses theSystem.Collections.Generic.Dictionary as the base class.

      public class MyDictionary : Dictionary<string, int> { }    public class MyMain  {      public MyMain()      {          MyDictionary dictionary = new MyDictionary();          dictionary.Add(\"hello\", 1);      }  }