title: C# Query: 'System.InvalidOperationException' | Additional information: Connection must be valid and open
body: <pre><code>connectionString = @"server=localhost;database=" + lbDatabase.SelectedItem.ToString() + ";userid=root;password=;";
  
          string query = "SELECT order_id FROM orders WHERE id = 1";
  
          MySqlConnection connect = new MySqlConnection(connectionString);
  
          MySqlCommand cmd = new MySqlCommand(query, connect);
  
          reader = cmd.ExecuteReader();
  </code></pre>
  
  <p>Hello,</p>
  
  <p>I have this problem when I run the following code. I get this not so very specific error:</p>
  
  <blockquote>
    <p>An unhandled exception of type 'System.InvalidOperationException'
    occurred in MySql.Data.dll</p>
    
    <p>Additional information: Connection must be valid and open.</p>
  </blockquote>
  
  <p>If anyone could help me out I would really appreciate it,</p>
  
  <p>Thank you.</p>