Hello,
I have problem with population DropDownList few times... First time is working, than I get first element choosed but rest of the list is empty:

                MainProgram.myConnectionHelper.Connection.Open();
                SqlCommand myCommand = new SqlCommand("SELECT Twr_Kod, Twr_Nazwa FROM Seven.TwrKarty WHERE Twr_Kod = 'W01 'or Twr_Kod = 'W06';", MainProgram.myConnectionHelper.Connection);
                //ddlRodzajMiesa.BeginUpdate(); 
                //ddlRodzajMiesa.DropDownStyle = RadDropDownStyle.DropDown;
                ddlRodzajMiesa.DataSource = null;
                ddlRodzajMiesa.ValueMember = "Twr_Kod";
                ddlRodzajMiesa.DisplayMember = "Twr_Nazwa";
                ddlRodzajMiesa.DataSource = myCommand.ExecuteReader();
                ddlRodzajMiesa.SelectedValue = 0;
                //ddlRodzajMiesa.DropDownStyle = RadDropDownStyle.DropDownList;
                //ddlRodzajMiesa.EndUpdate();
                MainProgram.myConnectionHelper.Connection.Close();



Thanks for any help in advance...

Hi Sebastian,

Thank you for writing.

I was not able to reproduce the observed behavior. This is why I attached my test project. Could you please check it and let me know how it differs from your real setup? 

I am converting this Forum thread into a support ticket in order to allow attachments.You can find it in your Telerik account.

I am looking forward to your reply.

Regards,
Dimitar
Telerik