ado.net后台代码

构造函数连接数据库：  public SqlHelper()           {             string conn = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;             conns = new SqlConnection(conn);            }        打开数据库连接：         private SqlConnection Getconn()         {             if (conns.State == ConnectionState.Closed)             {                 conns.Open();               }             return conns;         }

执行带参数的增删改： 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;         } 执行带参数的查询： public DataTable Execuquery(string cmdText, SqlParameter[] paras, CommandType ct)         {             DataTable dt = new DataTable();             using (cmd = new SqlCommand(cmdText, Getconn()))             {                 cmd.CommandType = ct;                 cmd.Parameters.AddRange(paras);                 sdr = cmd.ExecuteReader();                 dt.Load(sdr);                 sdr.Close();                 return dt;             }         }