Connection must be valid and open error

Question

I'm getting error: Connection must be valid and open when I start this program. I searched on google and only found 2 people that have the same error. Is it possible to fix this ?? Thx

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Data.Odbc;
using System.Data.Sql;
namespace WindowsFormsApplication1
{
static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        string connectionString = "Server=localhost;Uid=root;Pwd=******;Database=testing;";
        MySql.Data.MySqlClient.MySqlConnection connection = new MySql.Data.MySqlClient.MySqlConnection(connectionString);

        connection.Open();

        string insertQuery = "ALTER TABLE `user` ADD lol INT";
        MySql.Data.MySqlClient.MySqlCommand myCommand = new MySql.Data.MySqlClient.MySqlCommand(insertQuery);
        myCommand.ExecuteNonQuery();
        connection.Close();
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1());
    }
}
}

Why did you put the odbc tag ? This question has nothing to do with ODBC... — Thomas Levesque, Nov 20 '10 at 14:35
Hey, you asked the same thing one hour ago: http://stackoverflow.com/questions/4232943/database-query-c-not-working — Fernando, Nov 20 '10 at 14:36

score 21 · Accepted Answer · answered Nov 20 '10 at 14:33

21

You need to tell your command about your connection object. Add the connection parameter to this line:

MySql.Data.MySqlClient.MySqlCommand myCommand = new MySql.Data.MySqlClient.MySqlCommand(insertQuery, connection);

answered Nov 20 '10 at 14:33

Tahbaza

9,486
2
26
39

score 4 · Answer 2 · answered Nov 20 '10 at 14:33

4

Your command has no connection assignet to it. Try passing the connection to the the command's constructor like this:

MySql.Data.MySqlClient.MySqlCommand myCommand = new MySql.Data.MySqlClient.MySqlCommand(insertQuery, connection);

answered Nov 20 '10 at 14:33

Fernando

4,029
1
26
35

Connection must be valid and open error

2 Answers2

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