Question

Is it possible to have select all button in listbox? Any ideas how to implement it? Thanks.

Answer 1

// Set  - SelectionMode="Multiple" for your ListBox and then do

protected void LinkButton1_Click1(object sender, EventArgs e)
{
    foreach (ListItem li in ListBox1.Items)
    {
        li.Selected = true;
    }
}

Samples are available at:
http://forums.asp.net/t/1241640.aspx/1

and
http://www.aspnet101.com/2008/01/listbox-select-allselect-none/

and
select all items in the listbox in asp.net