一个ASP.NET的MYSQL的数据库操作类自己封装的

/** 
* 类说明：对mysql数据库的操作类 
*/ 
using System; 
using System.Data; 
using MySql.Data.MySqlClient; 


namespace Niunan.BYLW.Utility 
{ 
/// <summary>对MYSQL数据库的操作类 
/// 
/// </summary> 
public class MYSQLHelper 
{ 
private MySqlConnection conn = null; 
private MySqlCommand cmd = null; 
private MySqlDataReader sdr = null; 


public MYSQLHelper() 
{ 
//string connStr = WebConfigurationManager.ConnectionStrings["connStr"].ToString(); 
string connStr = "server=localhost;database=test;uid=root;pwd=123456;charset=utf8"; 
conn = new MySqlConnection(connStr); 
} 


/// <summary>创建Command对象 
/// 
/// </summary> 
/// <param name="sql">SQL语句</param> 
public void CreateCommand(string sql) 
{ 
conn.Open(); 
cmd = new MySqlCommand(sql, conn); 
} 


/// <summary>添加参数 
/// 
/// </summary> 
/// <param name="paramName">参数名称</param> 
/// <param name="value">值</param> 
public void AddParameter(string paramName, object value) 
{ 
cmd.Parameters.Add(new MySqlParameter(paramName, value)); 
} 


/// <summary>执行不带参数的增删改SQL语句 
/// 
/// </summary> 
/// <param name="cmdText">增删改SQL语句</param> 
/// <param name="ct">命令类型</param> 
/// <returns></returns> 
public bool ExecuteNonQuery() 
{ 
int res; 
try 
{ 
res = cmd.ExecuteNonQuery(); 
if (res > 0) 
{ 
return true; 
} 
} 
catch (Exception ex) 
{ 
throw ex; 
} 
finally 
{ 
if (conn.State == ConnectionState.Open) 
{ 
conn.Close(); 
} 
} 
return false; 
} 


/// <summary>执行查询SQL语句 
/// 
/// </summary> 
/// <param name="cmdText">查询SQL语句</param> 
/// <returns></returns> 
public DataTable ExecuteQuery() 
{ 
DataTable dt = new DataTable(); 
using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)) 
{ 
dt.Load(sdr); 
} 
return dt; 
} 


/// <summary>返回查询SQL语句查询出的结果的第一行第一列的值 
/// 
/// </summary> 
/// <returns></returns> 
public string ExecuteScalar() 
{ 
string res = ""; 
try 
{ 
object obj = cmd.ExecuteScalar(); 
if (obj != null) 
{ 
res = obj.ToString(); 
} 
} 
catch (Exception ex) 
{ 
throw ex; 
} 
finally 
{ 
if (conn.State == ConnectionState.Open) 
{ 
conn.Close(); 
} 
} 
return res; 
} 
} 
}