asp.net使用mysql数据库

Asp.net连接mysql 不推荐使用ODBC,推荐是用mysql官网提供的组件MySQL.Data.Dll，放在bin下面，添加引用即可

下面是封装的几个常用操作

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using MySql.Data.MySqlClient;
using System.Data;
using System.Text;

namespace WebApplication2
{
    public class DBHelper
    {
        public static string connectionString = "Host=127.0.0.1;UserName=root;Password=root;"
            +"Database=mmloo;Port=3306;CharSet=utf8;Allow Zero Datetime=true";

        public DBHelper(){}

        public static string DataTableToJson(DataTable dt)
        {
            StringBuilder jsonBuilder = new StringBuilder();
            jsonBuilder.Append("{"");
            jsonBuilder.Append(dt.TableName);
            jsonBuilder.Append("":[");
            jsonBuilder.Append("[");
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                jsonBuilder.Append("{");
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    jsonBuilder.Append(""");
                    jsonBuilder.Append(dt.Columns[j].ColumnName);
                    jsonBuilder.Append("":"");
                    jsonBuilder.Append(dt.Rows[i][j].ToString());
                    jsonBuilder.Append("",");
                }
                jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
                jsonBuilder.Append("},");
            }
            jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
            jsonBuilder.Append("]");
            jsonBuilder.Append("}");
            return jsonBuilder.ToString();
        }
        /// <summary>
        /// 执行sql语句，返回影响的记录数
        /// </summary>
        /// <param name="SQLString"></param>
        /// <returns></returns>
        public static int ExecuteNonQuery(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 (MySql.Data.MySqlClient.MySqlException e)
                    {
                        connection.Close();
                        throw e;
                    }
                }
            }
        }


        /// <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 static int ExecuteNonQuery(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 (MySql.Data.MySqlClient.MySqlException e)
                    {
                        throw e;
                    }
                }
            }
        }


        /// <summary> 
        /// 执行查询语句，返回DataTable 
        /// </summary> 
        /// <param name="SQLString">查询语句</param> 
        /// <returns>DataTable</returns> 
        public static DataTable ExecuteDataTable(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 (MySql.Data.MySqlClient.MySqlException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds.Tables[0];
            }
        }


        /// <summary> 
        /// 执行查询语句，返回DataSet 
        /// </summary> 
        /// <param name="SQLString">查询语句</param> 
        /// <returns>DataTable</returns> 
        public static DataTable ExecuteDataTable(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 (MySql.Data.MySqlClient.MySqlException ex)
                    {
                        throw new Exception(ex.Message);
                    }
                    return ds.Tables[0];
                }
            }
        }


        /// <summary>
        /// 创建cmd
        /// </summary>
        /// <param name="cmd"></param>
        /// <param name="conn"></param>
        /// <param name="trans"></param>
        /// <param name="cmdText"></param>
        /// <param name="cmdParms"></param>
        private static 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);
                }
            }
        }

    }
}