using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Type openType = typeof(Dictionary<, >);

        // Close the generic type by using TKey=String, TValue=Int32

        Type closedType = openType.MakeGenericType(typeof (String), typeof (Int32));

        // Construct an instance of the closed type

        Object o = Activator.CreateInstance(closedType);

        // Prove it worked

        Console.WriteLine(o.GetType());

    }

}