数据库助手类（SQLHelper）

对数据库的增删改查，可以通 用数据库助手类（牛腩新闻发布系统视频）

using System; using System.Collections.Generic; using System.Text; using System.Data; using System.Data.SqlClient; using System.Configuration; namespace DAL { /// <summary> /// 数据库助手类 /// </summary> public class SQLHelper { private SqlConnection conn = null; private SqlCommand cmd = null; private SqlDataReader sdr = null; public SQLHelper() { string connStr = ConfigurationManager.ConnectionStrings["连接字符串名"].ConnectionString; conn = new SqlConnection(connStr); } private SqlConnection GetConn() { if (conn.State == ConnectionState.Closed) { conn.Open(); } return conn; } /// <summary> /// 执行不带参数的增删改SQL语句或存储过程 /// </summary> /// <param name="cmdText">增删改SQL语句或存储过程</param> /// <param name="ct">命令类型</param> /// <returns></returns> public int ExecuteNonQuery(string cmdText, CommandType ct) { int res; using (cmd = new SqlCommand(cmdText, GetConn())) { cmd.CommandType = ct; res = cmd.ExecuteNonQuery(); } return res; } /// <summary> /// 执行带参数的增删改SQL语句或存储过程 /// </summary> /// <param name="cmdText">增删改SQL语句或存储过程</param> /// <param name="ct">命令类型</param> /// <returns></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; } /// <summary> /// 执行查询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="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; } /// <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; } } }