title: InvalidOperationException was unhandled
body: <p>I receive no errors when i compile the program, however as soon as I click the save button
  I receive 'InvalidOperationException was unhandled'. <em>cmd.ExecuteNonQuery();</em> Is then highlighted, ive spent a while on this and no luck. Hope you can help.</p>
  
  <pre><code>private void save_Click(object sender, EventArgs e)
  {
      MySqlConnection con = new MySqlConnection("host=" ";user="";password=""; database="" ;");
      con.Open();
  
      MySqlCommand cmd = new MySqlCommand("INSERT INTO Staff (username, password, FirstName, SecondName, Phone, Email, Role, Phone 2, Fax)" + "values" + "("+username+","+password+","+Fname+","+Lname+","+Phone+","+email+","+role+","+Phone2+","+Fax+")");
      cmd.BeginExecuteNonQuery();
      cmd.ExecuteNonQuery();
  
      con.Close();            
  
      MessageBox.Show("Data Inserted");
      con.Close();          
  }
  </code></pre>