系列文章

C#底层库–数据库访问帮助类（MySQL版）
本文链接：https://blog.csdn.net/youcheng_ge/article/details/126886379

C#底层库–JSON帮助类_详细（序列化、反序列化、list、datatable）
本文链接：https://blog.csdn.net/youcheng_ge/article/details/128805705

WebAPI项目发布和IIS部署
https://blog.csdn.net/youcheng_ge/article/details/126539836

---

---

前言

我能抽象出整个世界，但是我不能抽象你。 想让你成为私有常量，这样外部函数就无法访问你。 又想让你成为全局常量，这样在我的整个生命周期都可以调用你。 可惜世上没有这样的常量，我也无法定义你，因为你在我心中是那么的具体。

哈喽大家好，可以发现本文并没有归属我的任何一个专栏，因为我觉得放哪儿都不合适。我主要是想和大家分享我开发过程遇到的问题，以及我的解决方案。
可不要小看这些，或许你没有接触这个项目，但本文的解决方法一定会给你带来启发。

提示：本专栏为项目实战篇，未接触过项目开发的学生理解困难，不建议阅读。

---

一、面临问题

我所在的公司为生产型公司，业务运营会产生各种各样的单据，而这些单据往往需要“编号”区分。比如销售订单–销售订单号、采购订单–采购订单号、原材料出库单–出库单号、财务凭证单–凭证单号、仓库发货单–物流单号等。

这些业务单据号，可不是你想象的那么简单？可不是随机数、自增的IDID能够实现的。我们知道，每个部门有各自的业务，好的设计业务员看他们的单据号，即他们部门单据编号规则，就能够对业务进行分类，归属本单据走哪类处理流程。

显然，如果只是单纯的随机数、自增id无法实现这样的问题。

提示：这是业务部门给出的部分单据号，命令规则。

二、解决方案

2.1 可行性分析

如上图所示，业务部门给出的“编号规则”，基本是XXX+流水号 的形式。这是最初步的一个版本，如果再复杂一点，可以细分为 产品类型代号+日期缩写+流水号，再进行下一步细分，又可以分为 产品类型代号+日期缩写+员工代号+流水号等等。

那么我们必然要采用字符串拼接的形式，XXX是固定的值，保留；流水号是数值类型，需要依次往后1，2，3，4，5…往后编号，在程序中就是 +1操作。

所以，我们是不是要先获取上一次单据号，看流水号排到多少了，然后才能进行+1操作。我们就要查询数据库业务表，获得最大的流水号是多少。

2.2 采用方案

我们作为软件设计师，不能让程序员这么在代码里写大量取数，拼接字符串，这么瞎搞。这对于他们的工作量太大了，而且他们很容易出错，就算他们不出错。退一步来说，如果对于业务部门，哪天业务调整了，编号要变化，你是不是又要改程序？这显然太麻烦了。

所以我为了解决这个问题，我想开发一个专门的服务，统一生成这么个编号。

我将这服务通用化，对平台、开发语言的依赖要尽可能低，就是说，无论你用 电脑、平板、手机、浏览器还是以后的什么设备，都可以获取我的“自动编号”。

解决方案：①创建API应用接口 ②编写自动编号生成器 ③部署服务 ④客户端调用，获取自动编号。

三、软件开发（源码展示）

3.1 创建API项目

C#创建API项目，引入数据库访问帮助类（MySQL版）、字符串操作类等底层库，具体可以看我的专栏《C#底层库》。

3.2 创建数据实体

传入解析的数据类AutoCodeRuleModel.cs，我已定义好，照抄就行了。

using System;

namespace DLMESWebAPI
{
    public class AutoCodeRuleModel
    {
        public string 编号规则 { get; set; } //自动编号规则
        public string 表 { get; set; } //数据库表
        public string 字段 { get; set; } //表字段
    }
}

3.3 编写API基础库

这里就是一些封装的库，是我项目开发频繁使用的，包括：数据库连接、xml读写、字符串操作、SQL语句生成等等。
提示：如果对这些类库不了解，或者本文没有附全源码的，你可以关注我的专辑《C#底层库》，里面均有讲解的。

创建类 AutoCodeClient.cs

using DLMESWebAPI.Core;
using System;
using System.Data;

namespace DLMESWebAPI.BLL
{
    public class AutoCodeClient
    {
        /// <summary>
        /// 获取自动编号
        /// </summary>
        /// <param name="a_strAutoRule">编号规则</param>
        /// <param name="a_strCodeTable">表名</param>
        /// <param name="a_strCodeField">字段名</param>
        /// <returns></returns>
        public static string GetAutoCode(string a_strAutoRule, string a_strCodeTable, string a_strCodeField)
        {
            int a_CodeLength = 4;
            string[] array = a_strAutoRule.Split(new char[]
            {
                ',',
                ';'
            });
            if (array.Length > 1) //编号规则是否定义了流水号位数。
            {
                int.TryParse(array[1], out a_CodeLength);
                return AutoCodeClient.GetAutoCode(array[0], a_CodeLength, a_strCodeTable, a_strCodeField);
            }
            return AutoCodeClient.GetAutoCode(a_strAutoRule, a_CodeLength, a_strCodeTable, a_strCodeField);
        }

        public static string GetAutoCode(string a_strAutoRule, int a_CodeLength, string a_strCodeTable, string a_strCodeField)
        {
            string text = "";
            string text2 = "";
            checked
            {
                for (int i = 0; i < a_CodeLength; i++)
                {
                    text += "_";
                    text2 += "0";
                }
                string text3 = AutoCodeClient.ParseCodeRule(a_strAutoRule, a_CodeLength);
                string s = AutoCodeClient.ParseQueryRule(a_strAutoRule, a_CodeLength);
                int num = text3.IndexOf(text);

                MySQLHelper fetchData = new MySQLHelper();
                string text4 = "select {0} from {1} where {2} like {3} order by 1 desc LIMIT 0,1";

                text4 = string.Format(text4, new object[]
                {
                    string.Format("SUBSTRING({0}, {1}, {2})", a_strCodeField, num + 1, a_CodeLength),
                    a_strCodeTable,
                    a_strCodeField,
                    s.QuotedStr()
                });
                DataTable l_dt = fetchData.Query(text4).Tables[0];

                if (l_dt != null)
                {
                    string newValue;
                    if (l_dt.Rows.Count <= 0)
                    {
                        newValue = 1.ToString(text2);
                    }
                    else
                    {
                        text3.Substring(0, num);
                        if (text3.Length > num + 4)
                        {
                            text3.Substring(num + 4);
                        }
                        string s2 = l_dt.Rows[0][0].ToString();
                        int num2 = 0;
                        int.TryParse(s2, out num2);
                        num2++;
                        newValue = num2.ToString(text2);
                    }
                    text3 = text3.Replace(text, newValue);
                }

                return text3;
            }
        }

        public static string GetAutoCodeAlpha(string a_strAutoRule, string a_strCodeTable, string a_strCodeField)
        {
            int num = 1;
            string text = "";
            string str = "";
            checked
            {
                for (int i = 0; i < num; i++)
                {
                    text += "_";
                    str += "0";
                }
                string text2 = AutoCodeClient.ParseCodeRule(a_strAutoRule, num);
                string s = AutoCodeClient.ParseQueryRule(a_strAutoRule, num);
                int num2 = text2.IndexOf(text);

                MySQLHelper fetchData = new MySQLHelper();
                string text3 = "select top 1 {0} from {1} where {2} like {3} order by 1 desc";
                text3 = string.Format(text3, new object[]
                {
                    string.Format("SUBSTRING({0}, {1}, {2})", a_strCodeField, num2 + 1, num),
                    a_strCodeTable,
                    a_strCodeField,
                    s.QuotedStr()
                });
                DataTable l_dt = fetchData.Query(text3).Tables[0];

                if (l_dt != null)
                {
                    string newValue;
                    if (l_dt.Rows.Count <= 0)
                    {
                        newValue = "A";
                    }
                    else
                    {
                        text2.Substring(0, num2);
                        if (text2.Length > num2 + 4)
                        {
                            text2.Substring(num2 + 4);
                        }
                        string text4 = l_dt.Rows[0][0].ToString();
                        int num3 = 65;
                        if (text4.Length > 0)
                        {
                            num3 = (int)text4[0];
                        }
                        num3++;
                        if (num3 > 90)
                        {
                            return AutoCodeClient.GetAutoCodeAlpha2(a_strAutoRule, a_strCodeTable, a_strCodeField);
                        }
                        newValue = Convert.ToString((char)num3);
                    }
                    text2 = text2.Replace(text, newValue);
                }

                return text2;
            }
        }

        private static string GetAutoCodeAlpha2(string a_strAutoRule, string a_strCodeTable, string a_strCodeField)
        {
            int num = 2;
            string text = "";
            string str = "";
            checked
            {
                for (int i = 0; i < num; i++)
                {
                    text += "_";
                    str += "0";
                }
                string text2 = AutoCodeClient.ParseCodeRule(a_strAutoRule, num);
                string s = AutoCodeClient.ParseQueryRule(a_strAutoRule, num);
                int num2 = text2.IndexOf(text);

                MySQLHelper fetchData = new MySQLHelper();
                string text3 = "select top 1 {0} from {1} where {2} like {3} order by 1 desc";
                text3 = string.Format(text3, new object[]
                {
                    string.Format("SUBSTRING({0}, {1}, {2})", a_strCodeField, num2 + 1, num),
                    a_strCodeTable,
                    a_strCodeField,
                    s.QuotedStr()
                });
                DataTable l_dt = fetchData.Query(text3).Tables[0];
                if (l_dt != null)
                {
                    string newValue;
                    if (l_dt.Rows.Count <= 0)
                    {
                        newValue = "AA";
                    }
                    else
                    {
                        string input = l_dt.Rows[0][0].ToString();
                        newValue = AutoCodeClient.IncAlphaCode(input);
                    }
                    text2 = text2.Replace(text, newValue);
                }
                return text2;
            }
        }

        private static string IncAlphaCode(string input)
        {
            char c = input[0];
            char c2 = input[1];
            int num = (int)c;
            int num2 = (int)c2;
            checked
            {
                if (num2 < 90)
                {
                    return Convert.ToString((char)num) + Convert.ToString((char)(num2 + 1));
                }
                return Convert.ToString((char)(num + 1)) + "A";
            }
        }

        private static string ParseCodeRule(string a_strAutoRule, int a_CodeLength)
        {
            DateTime date = DateTime.Now.Date;
            if (a_strAutoRule.Contains("[紧缩天数]"))
            {
                a_strAutoRule = a_strAutoRule.Replace("[紧缩天数]", date.Day.ToString());
            }
            if (a_strAutoRule.Contains("[两位天数]"))
            {
                a_strAutoRule = a_strAutoRule.Replace("[两位天数]", date.Day.ToString("00"));
            }
            if (a_strAutoRule.Contains("[紧缩月份]"))
            {
                a_strAutoRule = a_strAutoRule.Replace("[两位月份]", date.Month.ToString());
            }
            if (a_strAutoRule.Contains("[两位月份]"))
            {
                a_strAutoRule = a_strAutoRule.Replace("[两位月份]", date.Month.ToString("00"));
            }
            checked
            {
                if (a_strAutoRule.Contains("[一位年份]"))
                {
                    a_strAutoRule = a_strAutoRule.Replace("[一位年份]", date.Year.ToString().Substring(date.Year.ToString().Length - 1, 1));
                }
                if (a_strAutoRule.Contains("[两位年份]"))
                {
                    a_strAutoRule = a_strAutoRule.Replace("[两位年份]", date.Year.ToString().Substring(date.Year.ToString().Length - 2, 2));
                }
                if (a_strAutoRule.Contains("[四位年份]"))
                {
                    a_strAutoRule = a_strAutoRule.Replace("[四位年份]", date.Year.ToString("0000"));
                }

                string text2 = "";
                for (int i = 0; i < a_CodeLength; i++)
                {
                    text2 += "_";
                }
                a_strAutoRule = a_strAutoRule.Replace("[流水编号]", text2);
                a_strAutoRule = a_strAutoRule.Replace("[按月编号]", text2);
                a_strAutoRule = a_strAutoRule.Replace("[按年编号]", text2);
                return a_strAutoRule;
            }
        }

        private static string ParseQueryRule(string a_strAutoRule, int a_CodeLength)
        {
            DateTime date = DateTime.Now.Date;
            if (a_strAutoRule.Contains("[紧缩天数]"))
            {
                a_strAutoRule = a_strAutoRule.Replace("[紧缩天数]", date.Day.ToString());
            }
            if (a_strAutoRule.Contains("[两位天数]"))
            {
                if (a_strAutoRule.Contains("[按月编号]") || a_strAutoRule.Contains("[按年编号]"))
                {
                    a_strAutoRule = a_strAutoRule.Replace("[两位天数]", "__");
                }
                else
                {
                    a_strAutoRule = a_strAutoRule.Replace("[两位天数]", date.Day.ToString("00"));
                }
            }
            if (a_strAutoRule.Contains("[紧缩月份]"))
            {
                a_strAutoRule = a_strAutoRule.Replace("[两位月份]", date.Month.ToString());
            }
            if (a_strAutoRule.Contains("[两位月份]"))
            {
                if (a_strAutoRule.Contains("[按年编号]"))
                {
                    a_strAutoRule = a_strAutoRule.Replace("[两位月份]", "__");
                }
                else
                {
                    a_strAutoRule = a_strAutoRule.Replace("[两位月份]", date.Month.ToString("00"));
                }
            }
            checked
            {
                if (a_strAutoRule.Contains("[一位年份]"))
                {
                    a_strAutoRule = a_strAutoRule.Replace("[一位年份]", date.Year.ToString().Substring(date.Year.ToString().Length - 1, 1));
                }
                if (a_strAutoRule.Contains("[两位年份]"))
                {
                    a_strAutoRule = a_strAutoRule.Replace("[两位年份]", date.Year.ToString().Substring(date.Year.ToString().Length - 2, 2));
                }
                if (a_strAutoRule.Contains("[四位年份]"))
                {
                    a_strAutoRule = a_strAutoRule.Replace("[四位年份]", date.Year.ToString("0000"));
                }
                
                string text2 = "";
                for (int i = 0; i < a_CodeLength; i++)
                {
                    text2 += "_";
                }
                a_strAutoRule = a_strAutoRule.Replace("[流水编号]", text2);
                a_strAutoRule = a_strAutoRule.Replace("[按月编号]", text2);
                a_strAutoRule = a_strAutoRule.Replace("[按年编号]", text2);
                return a_strAutoRule;
            }
        }
    }
}

创建数据库辅助类 MySQLHelper.cs

using System;
using System.Data;
using MySql.Data.MySqlClient;
using System.Collections.Generic;
using DLMESWebAPI.Core;

namespace DLMESWebAPI
{
    /// <summary>
    /// 数据访问抽象基础类
    /// </summary>
    public class MySQLHelper
    {
        //简单工厂模式：将类抽象化处理，编写工厂方法，将客户传入参数转换为对应的实例对象。
        public string server { get; set; }
        public string port { get; set; }
        public string uid { get; set; }
        public string pwd { get; set; }
        public string BaseName { get; set; }
        public string connectionString { get; set; }

        /// <summary>
        /// 构造函数
        /// </summary>
        public MySQLHelper()
        {
            this.server = AppConfig.GetValue("db_server");
            this.port = AppConfig.GetValue("db_port");
            this.BaseName = AppConfig.GetValue("db_base");
            this.uid = AppConfig.GetValue("db_uid");
            this.pwd = AppConfig.GetValue("db_pwd");

            this.connectionString = $"server={server};uid={uid};pwd={pwd};database={BaseName};SslMode=None;charset=utf8";
        }

        /// <summary>
        /// 构造函数
        /// </summary>
        public MySQLHelper(string server, string port, string uid, string pwd, string BaseName)
        {
            this.server = server;
            this.port = port;
            this.BaseName = BaseName;
            this.uid = uid;
            this.pwd = pwd;

            this.connectionString = $"server={server};uid={uid};pwd={pwd};database={BaseName};SslMode=None;charset=utf8";
        }

        #region 公用方法
        public bool Test()
        {
            string l_strSQL = "select 1 ";
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(l_strSQL, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return false;
                        }
                        else
                        {
                            return true;
                        }
                    }
                    catch (MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }



        /// <summary>
        /// 查询表是否存在
        /// </summary>
        /// <param name="strTableName">表名</param>
        /// <returns>bool</returns>
        public bool Exists(string strTableName)
        {
            string l_strSQL = "SHOW TABLES LIKE '" + strTableName+"'";
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(l_strSQL, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return false;
                        }
                        else
                        {
                            return true;
                        }
                    }
                    catch (MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }

        /// <summary>
        /// 查询数据是否存在，带参数
        /// </summary>
        /// <param name="strSql">查询语句</param>
        /// <param name="cmdParms">参数列表</param>
        /// <returns></returns>
        public bool Exists(string strSql, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(strSql, connection))
                {
                    cmd.Parameters.AddRange(cmdParms);
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return false;
                        }
                        else
                        {
                            return true;
                        }
                    }
                    catch (MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }


        /// <summary>
        /// 获取表中字段的最大值
        /// </summary>
        /// <param name="FieldName">列名</param>
        /// <param name="TableName">表名</param>
        /// <returns></returns>
        public int GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;

            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(strsql, connection))
                {
                    try
                    {
                        connection.Open();
                        object obj = cmd.ExecuteScalar();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return 1;
                        }
                        else
                        {
                            return int.Parse(obj.ToString()); ;
                        }
                    }
                    catch (MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }

        /// <summary>
        /// 执行查询语句，无参数，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public DataSet ShowDataBases(string SQLString)
        {
            string l_str = $"server={server};uid={uid};pwd={pwd};SslMode=None;";
            using (MySqlConnection connection = new MySqlConnection(l_str))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (MySqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }
        #endregion


        #region  执行简单SQL语句
        /// <summary>
        /// 执行SQL语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <returns>影响的记录数</returns>
        public int ExecuteSql(string SQLString)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }

        /// <summary>
        /// 执行SQL语句(带特殊文本)，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="strParamText">参数内容</param>
        /// <returns>影响的记录数</returns>
        public int ExecuteSql(string SQLString, string strParamText)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand(SQLString, connection);
                MySqlParameter myParameter = new MySqlParameter("@content", SqlDbType.NText);
                myParameter.Value = strParamText;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (MySqlException e)
                {
                    throw e;
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }

        /// <summary>
        /// 执行SQL语句(带参数)，返回影响的记录数
        /// </summary>
        /// <param name="SQLString">SQL语句</param>
        /// <param name="cmdParms">准备好的参数列表</param>
        /// <returns>影响的记录数</returns>
        public int ExecuteSql(string SQLString, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        int rows = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return rows;
                    }
                    catch (MySqlException e)
                    {
                        throw e;
                    }
                }
            }
        }



        /// <summary>
        /// 指定时间执行，返回影响行数
        /// </summary>
        /// <param name="SQLString">执行语句</param>
        /// <param name="Times">指定时间</param>
        /// <returns>影响的记录数</returns>
        public int ExecuteSqlByTime(string SQLString, int Times)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(SQLString, connection))
                {
                    try
                    {
                        connection.Open();
                        cmd.CommandTimeout = Times;
                        int rows = cmd.ExecuteNonQuery();
                        return rows;
                    }
                    catch (MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }


        /// <summary>
        /// 批量执行SQL语句，实现数据库事务，返回执行行数。
        /// </summary>
        /// <param name="SQLTextList">多条SQL语句</param>		
        public int ExecuteSqlTran(List<String> SQLTextList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                MySqlCommand cmd = new MySqlCommand();
                MySqlTransaction tx = conn.BeginTransaction();
                cmd.Transaction = tx;
                try
                {
                    int count = 0;
                    for (int n = 0; n < SQLTextList.Count; n++)
                    {
                        string strsql = SQLTextList[n];
                        if (strsql.Trim().Length > 1)
                        {
                            cmd.CommandText = strsql;
                            count += cmd.ExecuteNonQuery();
                        }
                    }
                    tx.Commit();
                    return count;
                }
                catch
                {
                    tx.Rollback();
                    return 0;
                }
            }
        }

        /// <summary>
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
        /// </summary>
        /// <param name="strSQL">SQL语句</param>
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
        /// <returns>影响的记录数</returns>
        public int ExecuteSqlInsertImg(string strSQL, byte[] fs)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand(strSQL, connection);
                MySqlParameter myParameter = new MySqlParameter("@fs", SqlDbType.Image);
                myParameter.Value = fs;
                cmd.Parameters.Add(myParameter);
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (MySqlException e)
                {
                    throw e;
                }
                finally
                {
                    cmd.Dispose();
                    connection.Close();
                }
            }
        }


        //执行单条插入语句，并返回id，不需要返回id的用ExceuteNonQuery执行。
        /// <summary>
        /// 执行插入语句并返回Id，不需返回Id的用其它执行方法
        /// </summary>
        /// <param name="strSql">Sql语句</param>
        /// <param name="parameters">此参数为Null时进行</param>
        /// <returns></returns>
        public int ExecuteInsert(string strSql, MySqlParameter[] parameters)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand(strSql, connection);
                try
                {
                    connection.Open();
                    if (parameters != null) cmd.Parameters.AddRange(parameters);
                    cmd.ExecuteNonQuery();
                    cmd.CommandText = @"select LAST_INSERT_ID()";
                    //此方法估计也可直接用  select   @@identity 获得，两值基本都是全局服务，使用时不能关闭Connection
                    int value = Int32.Parse(cmd.ExecuteScalar().ToString());
                    return value;
                }
                catch (Exception e)
                {
                    throw e;
                }
            }
        }

        /// <summary>
        /// 无参查询语句，返回MySqlDataReader ( 注意：调用该方法后，一定要对MySqlDataReader进行Close )
        /// </summary>
        /// <param name="strSqlText">查询语句</param>
        /// <returns>MySqlDataReader</returns>
        public MySqlDataReader ExecuteReader(string strSqlText)
        {
            MySqlConnection conn = new MySqlConnection(connectionString);
            MySqlCommand cmd = new MySqlCommand(strSqlText, conn);
            try
            {
                conn.Open();
                MySqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                return myReader;
            }
            catch (MySqlException e)
            {
                throw e;
            }
        }

        /// <summary>
        ///  带参查询语句，返回MySqlDataReader ( 注意：调用该方法后，一定要对MySqlDataReader进行Close )
        /// </summary>
        /// <param name="strSqlText">查询语句</param>
        /// <param name="cmdParas">参数列表</param>
        /// <returns>MySqlDataReader</returns>
        public MySqlDataReader ExecuteReader(string strSqlText, params MySqlParameter[] cmdParas)
        {
            MySqlConnection connection = new MySqlConnection(connectionString);
            MySqlCommand cmd = new MySqlCommand();
            try
            {
                PrepareCommand(cmd, connection, null, strSqlText, cmdParas);
                MySqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);//不加using，执行conn关闭后自动关闭Reader
                cmd.Parameters.Clear();
                return myReader;
            }
            catch (MySqlException e)
            {
                throw e;
            }
        }

        /// <summary>
        /// 执行查询语句，无参数，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataSet</returns>
        public DataSet Query(string SQLString)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (MySqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }

        /// <summary>
        /// 执行语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">Sql语句</param>
        /// <param name="Times">执行时间</param>
        /// <returns></returns>
        public DataSet Query(string SQLString, int Times)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (MySqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }
        /// <summary>
        /// 带参查询语句，返回DataSet
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <param name="cmdParms">参数列表</param>
        /// <returns>DataSet</returns>
        public DataSet Query(string SQLString, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand();
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                using (MySqlDataAdapter da = new MySqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                    }
                    catch (MySqlException ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    return ds;
                }
            }
        }




        /// <summary>
        /// 准备命令语句
        /// </summary>
        /// <param name="cmd">Command命令</param>
        /// <param name="conn">Connection对象</param>
        /// <param name="trans">是否是事务</param>
        /// <param name="cmdText">语句</param>
        /// <param name="cmdParms">参数列表</param>
        private void PrepareCommand(MySqlCommand cmd, MySqlConnection conn, MySqlTransaction trans, string cmdText, MySqlParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = CommandType.Text;//cmdType;
            if (cmdParms != null)
            {
                foreach (MySqlParameter parameter in cmdParms)
                {
                    if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&
                        (parameter.Value == null))
                    {
                        parameter.Value = DBNull.Value;
                    }
                    cmd.Parameters.Add(parameter);
                }
            }
        }

        #endregion

        #region 参数转换
        /// <summary>
        /// 准备MysqlCommad参数
        /// </summary>
        /// <param name="cmd">MySqlCommand cmd对象</param>
        /// <param name="conn">MySqlConnection conn对象</param>
        /// <param name="trans">数据库事务</param>
        /// <param name="cmdType">text or StoredProcedure</param>
        /// <param name="cmdText">存储过程名</param>
        /// <param name="cmdParms">SqlCommand的参数</param>
        private void PrepareMySqlCommand(MySqlCommand cmd, MySqlConnection conn, MySqlTransaction trans, CommandType cmdType, string cmdText, MySqlParameter[] cmdParms)
        {
            //连接状态是否打开
            if (conn.State != ConnectionState.Open)
                conn.Open();

            cmd.Connection = conn;
            cmd.CommandText = cmdText;

            //Transact-SQL 事务
            if (trans != null)
                cmd.Transaction = trans;
            cmd.CommandType = cmdType;
            if (cmdParms != null)
            {
                foreach (MySqlParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }

        /// <summary>
        /// 放回一个MakeMySqlParameter
        /// </summary>
        /// <param name="name">参数名字</param>
        /// <param name="type">参数类型</param>
        /// <param name="size">参数大小</param>
        /// <param name="value">参数值</param>
        /// <returns>SQLiteParameter的值</returns>
        public MySqlParameter MakeMySqlParameter(string name, MySqlDbType type, int size, object value)
        {
            MySqlParameter parm = new MySqlParameter(name, type, size);
            parm.Value = value;
            return parm;
        }
        /// <summary>
        /// 创建MysqlParameter
        /// </summary>
        /// <param name="name">字段名称</param>
        /// <param name="type">数据类型</param>
        /// <param name="value">字段值</param>
        /// <returns>返回类型为MySqlParameter</returns>
        public MySqlParameter MakeMySqlParameter(string name, MySqlDbType type, object value)
        {
            MySqlParameter parm = new MySqlParameter(name, type);
            parm.Value = value;
            return parm;
        }
        #endregion

        #region 存储过程的调用
        /// <summary>
        /// 无参存储过程，用于插入修改删除表数据，无返回值
        /// </summary>
        /// <param name="ProcText">存储过程脚本</param>
        public void ExecuteProc(string ProcText)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand(ProcText, connection))
                {
                    try
                    {
                        cmd.CommandType = CommandType.StoredProcedure;
                        connection.Open();
                        cmd.ExecuteScalar();
                    }
                    catch (MySqlException e)
                    {
                        connection.Close();
                        throw new Exception(e.Message);
                    }
                }
            }
        }


        /// <summary>
        /// 带参存储过程，无返回值
        /// </summary>
        /// <param name="ProcText">存储过程脚本</param>
        /// <param name="cmdParms">参数MySqlParameter[] cmdParms</param>
        public void ExecuteProc(string ProcText, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand())
                {
                    try
                    {
                        cmd.CommandType = CommandType.StoredProcedure;
                        PrepareMySqlCommand(cmd, connection, null, CommandType.StoredProcedure, ProcText, cmdParms);
                        cmd.ExecuteScalar();
                    }
                    catch (MySqlException e)
                    {
                        connection.Close();
                        throw new Exception(e.Message);
                    }
                }
            }
        }
        /// <summary>
        /// 无参存储过程，返回DataSet
        /// </summary>
        /// <param name="ProcText">存储过程脚本</param>
        /// <returns>返回DataSet</returns>
        public DataSet ExecuteProcDataset(string ProcText)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand();
                PrepareMySqlCommand(cmd, connection, null, CommandType.StoredProcedure, ProcText, null);
                using (MySqlDataAdapter da = new MySqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                    }
                    catch (MySqlException ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    return ds;
                }
            }
        }

        /// <summary>
        /// 带参存储过程，返回DataSet
        /// </summary>
        /// <param name="ProcText">存储过程名</param>
        /// <param name="cmdParms">参数MySqlParameter[] cmdParms</param>
        /// <returns>返回DataSet</returns>
        public DataSet ExecuteProcDataset(string ProcText, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                MySqlCommand cmd = new MySqlCommand();
                PrepareMySqlCommand(cmd, connection, null, CommandType.StoredProcedure, ProcText, cmdParms);
                using (MySqlDataAdapter da = new MySqlDataAdapter(cmd))
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        da.Fill(ds, "ds");
                        cmd.Parameters.Clear();
                    }
                    catch (MySqlException ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    return ds;
                }
            }
        }
        #endregion

        #region 预留代码暂时用不上
        /*
        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的MySqlParameter[]）</param>
        public  void ExecuteSqlTran(Hashtable SQLStringList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                using (MySqlTransaction trans = conn.BeginTransaction())
                {
                    MySqlCommand cmd = new MySqlCommand();
                    try
                    {
                        //循环
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Key.ToString();
                            MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Value;
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条语句，实现数据库事务
        /// </summary>
        /// <param name="cmdList">SQL语句的泛式表（key为sql语句，value是该语句的MySqlParameter[]）</param>
        /// <returns>返回影响行数</returns>
        public  int ExecuteSqlTran(List<CommandInfo> cmdList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                using (MySqlTransaction trans = conn.BeginTransaction())
                {
                    MySqlCommand cmd = new MySqlCommand();
                    try
                    {
                        int count = 0;
                        //循环
                        foreach (CommandInfo myDE in cmdList)
                        {
                            string cmdText = myDE.CommandText;
                            MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Parameters;
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);

                            if (myDE.EffentNextType == EffentNextType.WhenHaveContine || myDE.EffentNextType == EffentNextType.WhenNoHaveContine)
                            {
                                if (myDE.CommandText.ToLower().IndexOf("count(") == -1)
                                {
                                    trans.Rollback();
                                    return 0;
                                }

                                object obj = cmd.ExecuteScalar();
                                bool isHave = false;
                                if (obj == null && obj == DBNull.Value)
                                {
                                    isHave = false;
                                }
                                isHave = Convert.ToInt32(obj) > 0;

                                if (myDE.EffentNextType == EffentNextType.WhenHaveContine && !isHave)
                                {
                                    trans.Rollback();
                                    return 0;
                                }
                                if (myDE.EffentNextType == EffentNextType.WhenNoHaveContine && isHave)
                                {
                                    trans.Rollback();
                                    return 0;
                                }
                                continue;
                            }
                            int val = cmd.ExecuteNonQuery();
                            count += val;
                            if (myDE.EffentNextType == EffentNextType.ExcuteEffectRows && val == 0)
                            {
                                trans.Rollback();
                                return 0;
                            }
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                        return count;
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的MySqlParameter[]）</param>
        public  void ExecuteSqlTranWithIndentity(System.Collections.Generic.List<CommandInfo> SQLStringList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                using (MySqlTransaction trans = conn.BeginTransaction())
                {
                    MySqlCommand cmd = new MySqlCommand();
                    try
                    {
                        int indentity = 0;
                        //循环
                        foreach (CommandInfo myDE in SQLStringList)
                        {
                            string cmdText = myDE.CommandText;
                            MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Parameters;
                            foreach (MySqlParameter q in cmdParms)
                            {
                                if (q.Direction == ParameterDirection.InputOutput)
                                {
                                    q.Value = indentity;
                                }
                            }
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            foreach (MySqlParameter q in cmdParms)
                            {
                                if (q.Direction == ParameterDirection.Output)
                                {
                                    indentity = Convert.ToInt32(q.Value);
                                }
                            }
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }

        /// <summary>
        /// 执行多条SQL语句，实现数据库事务。
        /// </summary>
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的MySqlParameter[]）</param>
        public  void ExecuteSqlTranWithIndentity(Hashtable SQLStringList)
        {
            using (MySqlConnection conn = new MySqlConnection(connectionString))
            {
                conn.Open();
                using (MySqlTransaction trans = conn.BeginTransaction())
                {
                    MySqlCommand cmd = new MySqlCommand();
                    try
                    {
                        int indentity = 0;
                        //循环
                        foreach (DictionaryEntry myDE in SQLStringList)
                        {
                            string cmdText = myDE.Key.ToString();
                            MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Value;
                            foreach (MySqlParameter q in cmdParms)
                            {
                                if (q.Direction == ParameterDirection.InputOutput)
                                {
                                    q.Value = indentity;
                                }
                            }
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                            int val = cmd.ExecuteNonQuery();
                            foreach (MySqlParameter q in cmdParms)
                            {
                                if (q.Direction == ParameterDirection.Output)
                                {
                                    indentity = Convert.ToInt32(q.Value);
                                }
                            }
                            cmd.Parameters.Clear();
                        }
                        trans.Commit();
                    }
                    catch
                    {
                        trans.Rollback();
                        throw;
                    }
                }
            }
        }

        /// <summary>
        /// 执行一条计算查询结果语句，返回查询结果（object）。
        /// </summary>
        /// <param name="SQLString">计算查询结果语句</param>
        /// <param name="cmdParms">准备好的参数列表</param>
        /// <returns>查询结果（object）</returns>
        public  object GetSingle(string SQLString, params MySqlParameter[] cmdParms)
        {
            using (MySqlConnection connection = new MySqlConnection(connectionString))
            {
                using (MySqlCommand cmd = new MySqlCommand())
                {
                    try
                    {
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                        object obj = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                        {
                            return null;
                        }
                        else
                        {
                            return obj;
                        }
                    }
                    catch (MySqlException e)
                    {
                        throw e;
                    }
                }
            }
        }


       */

        #endregion
    }
}

创建字符串扩展类 StringExt.cs

namespace DLMESWebAPI.Core
{
    public static class StringExt
    {
        /// <summary>
        /// 给字符串两边添加单引号（同时会将内部单引号替换成双单引号）
        /// </summary>
        /// <param name="S"></param>
        /// <returns></returns>
        public static string QuotedStr(this string S)
        {
            return "'" + S.Replace("'", "''") + "'";
        }

        /// <summary>
        /// 给字符串两边添加括号
        /// </summary>
        /// <param name="str">字符串</param>
        /// <returns>返回带括号的字符串</returns>
        public static string BracketStr(this string S)
        {
            return "(" + S + ")";
        }

        /// <summary>
        /// 使用And连接两个SQL条件
        /// </summary>
        /// <param name="strCondition1"></param>
        /// <param name="strCondition2"></param>
        /// <returns></returns>
        public static string ConcatSQL(this string S, string strCondition2)
        {
            if (S.Trim() == "" || strCondition2.Trim() == "")
            {
                return S + strCondition2;
            }
            return S + " and " + strCondition2;
        }
    }
}

3.4 编写API控制器

Controllers文件夹下，创建类QRController.cs

我这里就只给你们提供，自动编号获取的函数。

     /// <summary>
        /// 自动编号
        /// </summary>
        /// <param name="a_objData">传入数据实体</param>
        /// <returns></returns>
        [HttpPost]
        public ActionResult GetAutoCode([FromBody] object a_objData)
        {
            string l_strErrorCode = "C04";//错误码
            ActionResult m_Result = new ActionResult();

            if (a_objData == null && a_objData.ToString().Length == 0)
            {
                m_Result.Validate = false;
                m_Result.RetInfo = new CRetInfo() { ErrorCode = l_strErrorCode + "1", IsSUCD = false, ErrorMsg = Const.ct_strIsNullParam };
                m_Result.Data = new CData() { Obj = null, Table = null, cByte = null, Tostring = "" };
                return m_Result;
            }

            string l_strData = a_objData.ToString();
            AutoCodeRuleModel l_DataModel = new AutoCodeRuleModel();
            try
            {
                l_DataModel = JsonConvert.DeserializeObject<AutoCodeRuleModel>(l_strData);
            }
            catch (Exception ex)
            {
                m_Result.Validate = false;
                m_Result.RetInfo = new CRetInfo() { ErrorCode = l_strErrorCode + "2", IsSUCD = false, ErrorMsg = Const.ct_strAnalysisFail + ex.Message };
                m_Result.Data = new CData() { Obj = null, Table = null, cByte = null, Tostring = "" };
                return m_Result;
            }

            //查询表是否存在
            MySQLHelper mySQL = new MySQLHelper();
            try
            {
                bool l_bExists = mySQL.Exists(l_DataModel.表);
                if (!l_bExists)
                {
                    m_Result.Validate = false;
                    m_Result.RetInfo = new CRetInfo() { ErrorCode = l_strErrorCode + "3", IsSUCD = false, ErrorMsg = Const.ct_strTableNotExists};
                    m_Result.Data = new CData() { Obj = null, Table = null, cByte = null, Tostring = "" };
                    return m_Result;
                }
            }
            catch (Exception ex)
            {
                m_Result.Validate = false;
                m_Result.RetInfo = new CRetInfo() { ErrorCode = l_strErrorCode + "4", IsSUCD = false, ErrorMsg = Const.ct_strFetchFail + ex.Message };
                m_Result.Data = new CData() { Obj = null, Table = null, cByte = null, Tostring = "" };
                return m_Result;
            }

            //取编号
            try
            {
                string l_strAutoCode = AutoCodeClient.GetAutoCode(l_DataModel.编号规则, l_DataModel.表, l_DataModel.字段);
                m_Result.Validate = true;
                m_Result.RetInfo = new CRetInfo() { ErrorCode = l_strErrorCode + "5", IsSUCD = true, ErrorMsg = Const.ct_strFetchSuccess };
                m_Result.Data = new CData() { Obj = null, Table = null, cByte = null, Tostring = l_strAutoCode };
            }
            catch (Exception ex)
            {
                m_Result.Validate = false;
                m_Result.RetInfo = new CRetInfo() { ErrorCode = l_strErrorCode + "6", IsSUCD = false, ErrorMsg = Const.ct_strFetchFail + ex.Message };
                m_Result.Data = new CData() { Obj = null, Table = null, cByte = null, Tostring = "" };
            }
            return m_Result;
        }

四、运行效果

4.1 调用方式

【业务编号】获取方式，已部署API服务，支持多端（pad、PC）获取业务编号。
URL： http://172.16.**.*:8888/API/QR/GetAutoCode
http请求方式：POST
数据类型：json
调用样例：
{
“编号规则”: “[一位年份]A0N[流水编号];6”,
“表”: “t_codenumbertest”,
“字段”: “编号”
}

4.2 参数说明

“编号规则”：自动编号的规则定义
“表”：业务编号最终，保存的数据库表。
“字段”：表字段。如“钨条标签打印纪录表”字段“钨条编号”是单据号，那么 表=“钨条标签打印纪录表”、字段=“钨条编号”
其它问题：
①编号规则可根据需求添加 “规则类型”，目前支持：
[一位年份]
[两位年份]
[四位年份]
[两位月份]
[紧缩天数] --10日以内的天数，占用1位
[两位天数]
[设备前缀]
[流水编号]
②规则中，“固定值”如何设置？
不加中括号 []，均为固定值，编码自动保留。
③规则中，流水号位数如何设置？
流水号默认4位，如果有特殊需要+分号+数字。如：“[流水编号];6”，是系统出6位流水号。
“编号规则”: “[一位年份]A0N[流水编号];6”,

4.3 运行效果

我采用Postman给你看一下效果，真实项目涉及公司机密，不便于展示。
① “编号规则”: “[一位年份]A0N[流水编号];6”,

② “编号规则”: “SO[四位年份][两位月份][流水编号];4”,

③ “编号规则”: “[两位年份][两位月份][流水编号]PZ;10”,

你想怎么定义规则，编号就怎么生成。

五、资源链接

略，联系我获取。