Listbox problem

I am binding xml data to a list box. It works fine and all the data is successfully added to the list box. However when the form is submitted and if i try to retrieve any vallue from the list box it gives me no value at all. It is always giving me the 0 index value.

On the other hand if i manually put data in a list box as shown below without any data binding, i can retrieve the value. Can anyone please tell me what is the problem.

<vbcode>
<asp:ListBox ID="List"
runat="server">

<asp:ListItem>Item 1</asp:ListItem>
<asp:ListItem>Item 2</asp:ListItem>
<asp:ListItem>Item 3</asp:ListItem>
<asp:ListItem>Item 4</asp:ListItem>

</asp:ListBox>
</vbcode>

Make sure you rebind it every time, usually in the OnLoad event of the page.