Database Conection C# ExecuteNonReader with MySql

Question

I have some issue's, ive seen a peace of code on the internet only this whas done with Oledb.

Now i have rewrited the code for MySQL.data.mysqlclient as followed:

MySqlDataReader dr = null;
        MySqlCommand cmd = null;
        string cmdstr = "SELECT * FROM users WHERE email='"+UsrName.Text+"' and password='"+PassWrd.Text+"' LIMIT 1";
        dr = cmd.ExecuteNonReader();
        cmd = new MySqlCommand(cmdstr, connection);
        cmd.Dispose();

        if (dr.Read() == true)
        {
            MessageBox.Show("Succesvol ingelogd");
        }
        else
        {
            MessageBox.Show("Geen juiste gegevens");
        }
        connection.Close();

    }

Now the problem is another method for dr = cmd.ExecuteNonReader().

UPDATE----------------

string server;
        string database;
        string uid;
        string password;
        server = "localhost";
        database = "cmstt";
        uid = "root";
        password = "";
        string connectionString;
        connectionString = "SERVER=" + server + ";" + "DATABASE=" +
        database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";

        MySqlConnection connection = new MySqlConnection(connectionString);

        connection.Open();

        MySqlDataReader dr = null;
        MySqlCommand cmd = null;
        string cmdstr = "SELECT * FROM users WHERE email='"+UsrName.Text+"' and pass='"+PassWrd.Text+"' LIMIT 1";
        dr = cmd.ExecuteReader();
        cmd = new MySqlCommand(cmdstr, connection);


        if (dr.Read() == true)
        {
            MessageBox.Show("Succesvol ingelogd");
        }
        else
        {
            MessageBox.Show("Geen juiste gegevens");
        }
        cmd.Dispose();
        connection.Close();

Your code clearly open to SQL Injection. Please use parameterized SQL like cmd.Parameters.Add("@email", email); — Soner Gönül
– Soner Gönül, Commented Dec 9, 2012 at 17:30
Oh yeah, Little Bobby tables. imgs.xkcd.com/comics/exploits_of_a_mom.png — Pacane
– Pacane, Commented Dec 9, 2012 at 17:35

Moiz · Accepted Answer · 2012-12-09 17:50:21Z

2

It will be ExecuteReader() not ExecuteNonReader()

// mention your connection and connection string here.

        connection.open()

        SqlDataReader dr = null;
        MySqlCommand cmd = null;
        string cmdstr = "SELECT * FROM users WHERE email='"+UsrName.Text+"' and password='"+PassWrd.Text+"' LIMIT 1";

        cmd = new MySqlCommand(cmdstr, connection);
        dr = cmd.ExecuteReader();

        if (dr.Read() == true)
        {
            MessageBox.Show("Succesvol ingelogd");
        }
        else
        {
            MessageBox.Show("Geen juiste gegevens");
        }
        connection.Close();

    }

edited Dec 9, 2012 at 17:50

answered Dec 9, 2012 at 17:27

Moiz

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2 Comments

Joshua Maerten Over a year ago

dr = cmd.ExecuteReader(); nullReferenceException was unhandled : Object reference not set to an instance of an object.

Moiz Over a year ago

make sure you have open connection of sql server.

kgu87 · Accepted Answer · 2012-12-09 17:26:41Z

0

You are disposing cmd prematurely. Dispose it just before you close the connection.

answered Dec 9, 2012 at 17:26

kgu87

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1 Comment

Joshua Maerten Over a year ago

connection is open and cmd is desposed before connection close. Still have the error

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