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;
            }
        }
    }