出现错误:myCommand_update.Connection.Open(); 在西线请大家帮看看:

[dongpo1]

下边的代码 ,提示 myCommand_update.Connection.Open(); 出错,为什么??

string myConnString="user id=sa;password=ddp;"+"initial catalog=use;"+"data source=192.168.10.19;"+"Connect Timeout=30";
string mySelectQuery = "SELECT * FROM [user] WHERE Userid='"+userid+"' AND Password='"+password+"'";
SqlConnection myConnection = new SqlConnection(myConnString);
SqlCommand myCommand = new SqlCommand(mySelectQuery,myConnection);
myConnection.Open();
SqlDataReader myReader;
myReader = myCommand.ExecuteReader();
if(myReader.Read())
{
DateTime datetime1 = DateTime.Now;
SqlCommand myCommand_update = new SqlCommand("UPDATE [user] SET datetime_temp='"+datetime1+"' WHERE userid='"+userid+"'",myConnection);
myCommand_update.Connection.Open();
myCommand_update.ExecuteNonQuery();
}

[rachy]

myCommand_update.Connection.Open();
去掉这句

[rachy]

因为连接myConnection的状态已经是打开的了

[thinkingforever]

myConnection在前面不是已经Open了吗?