如果没有new创建对象,后面的(8)mysqldatareader.Close(); 需要关闭吗?谢谢高人解答!!! (6) 用SqlDataReader对象读行 mysqldatareader.Read(); (7) 显示SqlDataReader对象中的数值 yourtextbox.Text=mysqldatareader = mysqlcommand.ExecuteReader(); mysqldatareader.Read(); this.hisname.Text = mysqldatareader["Name" ].ToString(); this.hissex.Text = mysqldatareader["Sex"].ToString(); this.hisadress.Text = mysqldatareader ["Address"].ToString(); this.hisbirthday.Text = mysqldatareader["Birthday"].ToString(); mysqldatareader.Close
mysqlcon.Close();
mysqlcon.Dispose();
}
#endregion
#region 创建MySqlDataReader 对象
///
MySqlDataReader: 包含sql语句执行的结果,并提供一个方法从结果中阅读一行。 MySqlTransaction: 代表一个SQL事务在一个MySQL数据库。 查询结果是返回MySqlDataReader对象,MySqlDataReader包含sql语句执行的结果,并提供一个方法从结果中阅读一行。 1) 查询 a.查询条件固定 string sql= "select * from user"; MySqlCommand cmd = new MySqlCommand(sql,conn); MySqlDataReader reader =cmd.ExecuteReader();//执行ExecuteReader()返回一个MySqlDataReader对象 while (reader.Read())//初始索引是-1, ); cmd.Parameters.AddWithValue("para1", username); cmd.Parameters.AddWithValue("para2", password); MySqlDataReader
set; } public STATE state { get; set; } public Email() { } public Email(MySqlDataReader 获取User实例 /// /// <param name="reader">MySqlDataReader实例</param> public void LoadFromReader(MySqlDataReader reader) { id = reader[0].ToString().ToInt(); 获取User实例 /// /// <param name="reader">MySqlDataReader实例</param> public void LoadFromReader(MySqlDataReader reader) { id = reader[0].ToString().ToInt();
在做数据库的查询过程中,使用方法ExecuteReader,其返回结果为MySqlDataReader,由于参考的信息有误,走了好长时间的弯路,记录下来; string connectionStr string sqlContent = "select * from t_user"; MySqlConnection sqlConnection = null; MySqlDataReader
( 注意:调用该方法后,一定要对MySqlDataReader进行Close ) /// /// <param name="strSQL">查询语句 </param> /// <returns>MySqlDataReader</returns> public static MySqlDataReader ExecuteReader strSQL, connection); try { connection.Open(); MySqlDataReader ( 注意:调用该方法后,一定要对MySqlDataReader进行Close ) /// /// <param name="strSQL">查询语句 </param> /// <returns>MySqlDataReader</returns> public static MySqlDataReader ExecuteReader
sqlC.Open(); MySqlCommand Sqlquery = new MySqlCommand("show tables", sqlC); // MySqlDataReader
查询表格中的所有数据 MySqlCommand mySqlCommand = new MySqlCommand(sql, mysql); MySqlDataReader username字段的值 MySqlCommand mySqlCommand = new MySqlCommand(sql, mysql); MySqlDataReader
cmd.CommandText = "select * from info"; cmd.CommandType = CommandType.Text; using (MySqlDataReader
""; OpenDatabase(); MySqlCommand cmd = new MySqlCommand("SELECT * FROM contents", con); MySqlDataReader
conn.Open(); cmd.CommandText = "SELECT * FROM t_customers"; using (MySqlDataReader
MySqlCommand cmd = new MySqlCommand("select * from userinfo where name ='plane'",conn); //解析数据 MySqlDataReader
parameters</param> /// <returns>SqlDataReader type of data collection</returns> public static MySqlDataReader { PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters); MySqlDataReader email"; MySqlParameter commandParameters = new MySqlParameter("@email", email); MySqlDataReader
连接必须先打开数据库 20 cmd.CommandText = "Select * from T_Users"; 21 using (MySqlDataReader conn.Open(); 33 cmd.CommandText = "select * from t_users "; 34 using (MySqlDataReader { 41 conn.Open(); 42 cmd.CommandText = "select * from t_users"; 43 using (MySqlDataReader conn.CreateCommand()) 75 { 76 conn.Open(); 77 cmd.CommandText = "select * from t_users"; 78 using (MySqlDataReader cmd.CommandText = sql; cmd.Parameters.AddRange(parameters); using (MySqlDataReader
MySsqlCommand MySqlCommand cmd = new MySqlCommand(sql, sqlCon); //执行SQL并且返回查询结果 MySqlDataReader
Conn.Open(); } } // 查询,获取DataReader public static MySqlDataReader
我得到它 不能隐式转换类型“MySql.Data.MySqlDataReader”到 “System.Data.SqlClient的。 SqlDataReader’ 我在做什么错在这里?
null) { cmd.Parameters.AddRange(pms); } conn.Open(); return cmd.ExecuteScalar(); } } } public static MySqlDataReader
{ return command(sql).ExecuteNonQuery(); } //返回查询结果的方法 public MySqlDataReader
MySsqlCommand MySqlCommand cmd = new MySqlCommand(sql, sqlCon); //执行SQL并且返回查询结果 MySqlDataReader