Question

I’m adding data to my listbox using this code :

    SqlCommand cmd1 = new SqlCommand("SELECT U_Naam, U_Voornaam, User_ID FROM Login ORDER BY U_Naam ASC", con);
    dr = cmd1.ExecuteReader();

    int teller = 0;

    while (dr.Read())
    {
        hulp = dr["U_Naam"].ToString() + " " + dr["U_Voornaam"].ToString();
        lbNiet.Items.Add(hulp);
        lbNiet.Items[teller].Value = dr["User_ID"].ToString();
        teller++;
    }

When I run the program and select an item in the list I want to get it’s value (Using selectedvalue). When I do this it allways gives a nullref (no value). I’ve read somewhere the selected item is lost after a postback ? How can I solve this ?

thanks !

Answer 1

I don’t think the selected item is lost after PostBack under normal circumstances – my guess is that you are accidently populating the ListBox again after PostBack so that when you make a selection, the system hits the Page_Init / Page_Load (or whatever event you choose to populate the ListBox in) and recreates all the options. Doing this would overwrite the currently selected option.

If that’s the case it’s easily avoided by check for PostBack first before repopulating the list.