C# 拓展方法的简单实例

/// <summary>
    /// 扩展类
    /// </summary>
    public static class extend
    {
        /// <summary>
        /// 扩展join方法
        /// 把数组分割
        /// 截取最后一位
        /// </summary>
        /// <param name="s"></param>
        /// <param name="separotor">间隔符号</param>
        /// <param name="value">数组</param>
        /// <returns></returns>
        public static string e_join(this string [] value,string separotor)
        {
            string str = string.join(separotor, value);
            if (str.length >= 2)
            {
                return str.substring(0, str.length - 1);
            }
            else
            {
                return str;
            }
        }
    }