C# ASP.NET Simple Select Problem

Question

I am having a problem is getting a value from mysql using c#. The connection string is right, but it throws the following error: Invalid attempt to access a field before calling Read()

Can anyone tell me the problem which occurs in the code below

            string strConnection = ConfigurationSettings.AppSettings["ConnectionString"];
            MySqlConnection connection = new MySqlConnection(strConnection);
            MySqlCommand command = connection.CreateCommand();
            MySqlDataReader reader;
            command.CommandText = "SELECT application_domain_name FROM `test`.`application_domains` WHERE idapplication_domains = " + reference;
            connection.Open();
            reader = command.ExecuteReader();

            lblApplicationDomain.Text = reader.GetString(0);

            connection.Close();

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Joe Stefanelli
– Joe Stefanelli

2011-06-01 18:46:32 +00:00
Commented Jun 1, 2011 at 18:46 — Joe Stefanelli
– Joe Stefanelli, Commented Jun 1, 2011 at 18:46

aL3891 · Accepted Answer · 2011-06-01 18:47:19Z

2

You must call reader.Read() before accessing the results. Before you do that, the reader 'cursor' will be placed before the first element. Placing the cursor before the first element will make the behavior consistent even if the result set is empty.

edited Jun 1, 2011 at 18:47

answered Jun 1, 2011 at 18:44

aL3891

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Comments

Tejs · Accepted Answer · 2011-06-01 18:46:09Z

0

You need to call reader.Read() at least once. Like a normal SqlDataReader, the pattern is like so:

while(reader.Read())
{
    .. Do Stuff
}

while(sqlDataReader.MoveNext())
{
   .. Do Stuff
}

answered Jun 1, 2011 at 18:46

Tejs

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