Question

I’m trying to build an ‘edit’ page for a database record that can be edited and saved back to the database. One of the fields will be a multi-select listbox that will need to highlight the appropriate list items in a hard-coded list when loaded.

Using C#, how do I populate a multi-select listbox — with the appropriate items selected — based on the comma-delimited string from a database field? I’ve researched a few solutions that involve loops, but I have been unable to get them to work with my limited C# skillset.

This is all I have now, before I got stuck. You’ll see that it doesn’t account for multiple values in the string. Is there a function like ‘contains’ that I can check to see if the value matches? I’m still missing some (probably basic) C# logic and coding here.

int i; for (i = 0; i <= CATEGORYListBox.Items.Count - 1; i++) {     if (reader['CATEGORY'].ToString() == CATEGORYListBox.Items(i).Value)     {         CATEGORYListBox.Items(i).Selected = True;                        } } 

…

<asp:ListBox ID='CATEGORYListBox' runat='server'>     <asp:ListItem Value='Circulation'>Circulation</asp:ListItem>     <asp:ListItem Value='Interactive Media'>Interactive Media</asp:ListItem>     <asp:ListItem Value='Classified'>Classified</asp:ListItem>     <asp:ListItem Value='Publishing'>Publishing</asp:ListItem>     <asp:ListItem Value='Editorial'>Editorial</asp:ListItem>     <asp:ListItem Value='Retail'>Retail</asp:ListItem>  </asp:ListBox> 

Thanks everyone.

Answer 1

This is brute force and ugly, but it should work. It looks like your code above is some sort of hybrid between VB and C#. The code below is C# only. Also, consider not doing your ADO.Net in your codebehind.

for (int i = 0; i < CATEGORYListBox.Items.Count; i++) {     foreach (string category in reader['CATEGORY'].ToString().Split(','))     {         if (category != CATEGORYListBox.Items[i].Value) continue;         CATEGORYListBox.Items[i].Selected = true;         break;     } }