C#で可変長引数を使うには params ref: http://qiita.com/items/b8327999fd835132cb7a

SampleParams.cs

using System;
using System.Linq;

namespace SampleParams
{
    class Program
    {
        public static void Main(string[] args)
        {
            Console.WriteLine("Sum={0}",Sum(1,2,3,4,5));
            Console.ReadKey(true);
        }

        public static int Sum(params int [] values)
        {
            return values.Sum();
        }
    }
}