/// <summary>
        /// 转换数字金额主函数（包括小数）
        /// </summary>
        /// <param name="str">数字字符串</param>
        /// <returns>转换成中文大写后的字符串或者出错信息提示字符串</returns>
        public string convertsum(string str)
        {
            if (!ispositvedecimal(str))
                return "输入的不是正数字！";
            if (double.Parse(str) > 999999999999.99)
                return "数字太大，无法换算，请输入一万亿元以下的金额";
            char[] ch = new char[1];
            ch[0] = '.'; //小数点
            string[] Splitstr = null; //定义按小数点分割后的字符串数组
            Splitstr = str.Split(ch[0]);//按小数点分割字符串
            if (Splitstr.Length == 1) //只有整数部分
                return convertdata(str) + "圆整";
            else //有小数部分
            {
                string rstr;
                rstr = convertdata(Splitstr[0]) + "圆";//转换整数部分
                rstr += convertxiaoshu(Splitstr[1]);//转换小数部分
                return rstr;
            }
        }
        /// <summary>
        /// 判断是否是正数字字符串
        /// </summary>
        /// <param name="str">判断字符串</param>
        /// <returns>如果是数字，返回true，否则返回false</returns>
        public bool ispositvedecimal(string str)
        {
            decimal d;
            try
            {
                d = decimal.Parse(str);

            }
            catch (Exception)
            {
                return false;
            }
            if (d > 0)
                return true;
            else
                return false;
        }
        /// <summary>
        /// 转换数字（整数）
        /// </summary>
        /// <param name="str">需要转换的整数数字字符串</param>
        /// <returns>转换成中文大写后的字符串</returns>
        public string convertdata(string str)
        {
            string tmpstr = "";
            string rstr = "";
            int strlen = str.Length;
            if (strlen <= 4)//数字长度小于四位
            {
                rstr = convertdigit(str);

            }
            else
            {

                if (strlen <= 8)//数字长度大于四位，小于八位
                {
                    tmpstr = str.Substring(strlen - 4, 4);//先截取最后四位数字
                    rstr = convertdigit(tmpstr);//转换最后四位数字
                    tmpstr = str.Substring(0, strlen - 4);//截取其余数字
                    //将两次转换的数字加上萬后相连接
                    rstr = string.Concat(convertdigit(tmpstr) + "萬", rstr);
                    rstr = rstr.Replace("零萬", "萬");
                    rstr = rstr.Replace("零零", "零");

                }
                else
                    if (strlen <= 12)//数字长度大于八位，小于十二位
                    {
                        tmpstr = str.Substring(strlen - 4, 4);//先截取最后四位数字
                        rstr = convertdigit(tmpstr);//转换最后四位数字
                        tmpstr = str.Substring(strlen - 8, 4);//再截取四位数字
                        rstr = string.Concat(convertdigit(tmpstr) + "萬", rstr);
                        tmpstr = str.Substring(0, strlen - 8);
                        rstr = string.Concat(convertdigit(tmpstr) + "億", rstr);
                        rstr = rstr.Replace("零億", "億");
                        rstr = rstr.Replace("零萬", "零");
                        rstr = rstr.Replace("零零", "零");
                        rstr = rstr.Replace("零零", "零");
                    }
            }
            strlen = rstr.Length;
            if (strlen >= 2)
            {
                switch (rstr.Substring(strlen - 2, 2))
                {
                    case "佰零": rstr = rstr.Substring(0, strlen - 2) + "佰"; break;
                    case "仟零": rstr = rstr.Substring(0, strlen - 2) + "仟"; break;
                    case "萬零": rstr = rstr.Substring(0, strlen - 2) + "萬"; break;
                    case "億零": rstr = rstr.Substring(0, strlen - 2) + "億"; break;

                }
            }

            return rstr;
        }
        /// <summary>
        /// 转换数字（小数部分）
        /// </summary>
        /// <param name="str">需要转换的小数部分数字字符串</param>
        /// <returns>转换成中文大写后的字符串</returns>
        public string convertxiaoshu(string str)
        {
            int strlen = str.Length;
            string rstr;
            if (strlen == 1)
            {
                rstr = convertchinese(str) + "角";
                return rstr;
            }
            else
            {
                string tmpstr = str.Substring(0, 1);
                rstr = convertchinese(tmpstr) + "角";
                tmpstr = str.Substring(1, 1);
                rstr += convertchinese(tmpstr) + "分";
                rstr = rstr.Replace("零分", "");
                rstr = rstr.Replace("零角", "");
                return rstr;
            }


        }

        /// <summary>
        /// 转换数字
        /// </summary>
        /// <param name="str">转换的字符串（四位以内）</param>
        /// <returns></returns>
        public string convertdigit(string str)
        {
            int strlen = str.Length;
            string rstr = "";
            switch (strlen)
            {
                case 1: rstr = convertchinese(str); break;
                case 2: rstr = convert2digit(str); break;
                case 3: rstr = convert3digit(str); break;
                case 4: rstr = convert4digit(str); break;
            }
            rstr = rstr.Replace("拾零", "拾");
            strlen = rstr.Length;

            return rstr;
        }
        /// <summary>
        /// 转换四位数字
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public string convert4digit(string str)
        {
            string str1 = str.Substring(0, 1);
            string str2 = str.Substring(1, 1);
            string str3 = str.Substring(2, 1);
            string str4 = str.Substring(3, 1);
            string rstring = "";
            rstring += convertchinese(str1) + "仟";
            rstring += convertchinese(str2) + "佰";
            rstring += convertchinese(str3) + "拾";
            rstring += convertchinese(str4);
            rstring = rstring.Replace("零仟", "零");
            rstring = rstring.Replace("零佰", "零");
            rstring = rstring.Replace("零拾", "零");
            rstring = rstring.Replace("零零", "零");
            rstring = rstring.Replace("零零", "零");
            rstring = rstring.Replace("零零", "零");
            return rstring;
        }
        /// <summary>
        /// 转换三位数字
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public string convert3digit(string str)
        {
            string str1 = str.Substring(0, 1);
            string str2 = str.Substring(1, 1);
            string str3 = str.Substring(2, 1);
            string rstring = "";
            rstring += convertchinese(str1) + "佰";
            rstring += convertchinese(str2) + "拾";
            rstring += convertchinese(str3);
            rstring = rstring.Replace("零佰", "零");
            rstring = rstring.Replace("零拾", "零");
            rstring = rstring.Replace("零零", "零");
            rstring = rstring.Replace("零零", "零");
            return rstring;
        }
        /// <summary>
        /// 转换二位数字
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public string convert2digit(string str)
        {
            string str1 = str.Substring(0, 1);
            string str2 = str.Substring(1, 1);
            string rstring = "";
            rstring += convertchinese(str1) + "拾";
            rstring += convertchinese(str2);
            rstring = rstring.Replace("零拾", "零");
            rstring = rstring.Replace("零零", "零");
            return rstring;
        }
        /// <summary>
        /// 将一位数字转换成中文大写数字
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public string convertchinese(string str)
        {
            //"零壹贰叁肆伍陆柒捌玖拾佰仟萬億圆整角分"
            string cstr = "";
            switch (str)
            {
                case "0": cstr = "零"; break;
                case "1": cstr = "壹"; break;
                case "2": cstr = "贰"; break;
                case "3": cstr = "叁"; break;
                case "4": cstr = "肆"; break;
                case "5": cstr = "伍"; break;
                case "6": cstr = "陆"; break;
                case "7": cstr = "柒"; break;
                case "8": cstr = "捌"; break;
                case "9": cstr = "玖"; break;
            }
            return (cstr);
        }