How to constrain generic type to must have a construtor that takes certain parameters?

Question

I have a wrapper generic class that intended to be used with a set of types. Those types are generated by a utility and are all derived from a base class ClientBase. While C

Answer 1

Here is a full working example based on @JonSkeet answer:

using System;
using System.Collections.Generic;

namespace GenericProxy
{
    class Program
    {
        static void Main()
        {
            GenericProxy proxy = new GenericProxy(ClientBase.Factory, "cream");

            Console.WriteLine(proxy.Proxy.ConfigName); // test to see it working
        }
    }

    public class ClientBase
    {
        static public ClientBase Factory(string configName)
        {
            return new ClientBase(configName);
        }

        // default constructor as required by new() constraint
        public ClientBase() { }

        // constructor that takes arguments
        public ClientBase(string configName) { _configName = configName; }

        // simple method to demonstrate working example
        public string ConfigName
        {
            get { return "ice " + _configName; }
        }

        private string _configName;
    }

    public class GenericProxy
        where T : ClientBase, new()
    {
        public GenericProxy(Func factory, string configName)
        {
            Proxy = factory(configName);
        }

        public T Proxy { get; private set; }
    }
}

Expect to see the following output: ice cream