.NET Framework3.5扩展方法使用示例

using System;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("a,b,c".Split(",").Length);
            Console.ReadKey();
        }
    }

    /// <summary>
    /// 扩展方法类
    /// </summary>
    static class Extensions
    {
        /// <summary>
        /// 使用指定分隔符分割字符串,返回一字符串数组
        /// </summary>
        /// <param name="str"></param>
        /// <param name="separator"></param>
        /// <returns></returns>
        public static string[] Split(this string str, string separator)
        {
            return str.Split(new string[] { separator }, StringSplitOptions.None);
        }
    }
}