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if (mysqlReader2[0].ToString() != "0" )
connection = new MySql.Data.MySqlClient.MySqlConnection(MyConnectionString);
connection.Open();
MySqlCommand cmd_board = connection.CreateCommand();
MySqlCommand cmd_board2 = connection.CreateCommand();
cmd_board.CommandText = "SELECT wr_2 FROM gs_write_" + config.my_serv_table + " WHERE wr_1 != 1 AND wr_subject !='' LIMIT 0,5 ";
cmd_board2.CommandText = "SELECT count(*) as count1 FROM gs_write_" + config.my_serv_table + " WHERE wr_1 != 1 AND wr_subject !='' LIMIT 0,5 ";
MySql.Data.MySqlClient.MySqlDataReader mysqlReader1 = cmd_board.ExecuteReader();
MySql.Data.MySqlClient.MySqlDataReader mysqlReader2 = cmd_board2.ExecuteReader();
if (mysqlReader2[0].ToString() != "0" )
{
linkLabel1.Text = "";
while (mysqlReader1.Read())
{
if (mysqlReader1["wr_2"].ToString().Length > 10)
{
linkLabel1.Text += "\n" + mysqlReader1["wr_2"].ToString().Substring(0, 10) + "\n";
}
else
{
linkLabel1.Text += "\n" + mysqlReader1["wr_2"].ToString() + "\n";
}
}
}
while(reader.Read()){ string name = reader["name"].ToString(); // name为查询语句中的name列}
注意
使用datareader必须及时关闭,否则会与数据库建立长连接,消耗数据库的连接数。关闭连接使用Close()方法或使用Using方法让系统帮你自动释放。
如果datareader没有进行关闭,当程序存在若干未关闭的datareader的时候,客户端会连不上数据库的。