SQLHelper助手类

/*
* 创建时间：2013-10-12 14:52
* 说明：数据库助手类
*/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace DAL
{
public class SQLHelper
{
private SqlConnection conn = null;
private SqlCommand cmd = null;
private SqlDataReader sdr = null;
public SQLHelper()
{
string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
conn = new SqlConnection(connStr);
}

private SqlConnection GetConn()
{
if (conn.State == ConnectionState.Closed)
{
conn.Open();
}
return conn;
}

#region 执行不带参数的SQL增删改语句或存储过程
/// <summary>
/// 执行不带参数的SQL增删改语句或存储过程
/// </summary>
/// <param name="cmdText">SQL增删改语句或存储过程</param>
/// <param name="ct">命令类型</param>
/// <returns>返回更新记录数</returns>
public int ExecuteNonQuery(string cmdText,CommandType ct)
{
int res;
try
{
cmd = new SqlCommand(cmdText, GetConn());
cmd.CommandType = ct;
res = cmd.ExecuteNonQuery();
}
catch (Exception ex)
{

throw ex;
}
finally
{
if (conn.State==ConnectionState.Open)
{
conn.Close();
}
}
return res;
}
#endregion

#region 执行带参数的SQL增删改语句或存储过程
/// <summary>
/// 执行带参数的SQL增删改语句或存储过程
/// </summary>
/// <param name="cmdText">SQL增删改语句或存储过程</param>
/// <param name="paras">参数集合</param>
/// <param name="ct">命令类型</param>
/// <returns>返回更新的记录数</returns>
public int ExecuteNonQuery(string cmdText, SqlParameter[] paras,CommandType ct)
{
int res;
using (cmd = new SqlCommand(cmdText, GetConn()))
{
cmd.CommandType = ct;
cmd.Parameters.AddRange(paras);
res = cmd.ExecuteNonQuery();
}
return res;
}
#endregion

#region 执行不带参数的SQL查询语句或存储过程
/// <summary>
/// 执行不带参数的SQL查询语句或存储过程
/// </summary>
/// <param name="cmdText">SQL查询语句或存储过程</param>
/// <param name="ct">命令类型</param>
/// <returns></returns>
public DataTable ExecuteQuery(string cmdText,CommandType ct)
{
DataTable dt = new DataTable();
cmd = new SqlCommand(cmdText, GetConn());
cmd.CommandType = ct;
using(sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
{
dt.Load(sdr);
}
return dt;
}
#endregion

#region 执行带参数的查询SQL语句或存储过程
/// <summary>
/// 执行带参数的查询SQL语句或存储过程
/// </summary>
/// <param name="cmdText">查询SQL语句或存储过程</param>
/// <param name="paras">参数集合</param>
/// <param name="ct">命令类型</param>
/// <returns></returns>
public DataTable ExecuteQuery(string cmdText, SqlParameter[] paras, CommandType ct)
{
DataTable dt = new DataTable();
cmd = new SqlCommand(cmdText, GetConn());
cmd.CommandType = ct;
cmd.Parameters.AddRange(paras);
using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
{
dt.Load(sdr);
}
return dt;
}
#endregion

#region 返回执行不带参数的SQL语句的第一行第一列的值
/// <summary>
/// 返回执行不带参数的SQL语句的第一行第一列的值
/// </summary>
/// <param name="cmdText">SQL语句</param>
/// <returns></returns>
public string ExecuteScalar(string cmdText)
{
try
{
cmd = new SqlCommand(cmdText, GetConn());
object obj = cmd.ExecuteScalar();
if (obj!=null)
{
return obj.ToString();
}
return "";
}
catch (Exception ex)
{

throw ex;
}
finally
{
if (conn.State == ConnectionState.Open)
{
conn.Close();
}
}
}
#endregion

}
}