Listbox in asp.net not getting selected items

Question

I have multiple dropdown & listbox in my webpage.

I am trying to get a list of CategoryID from a lstCatID listbox i am able to populate

Answer 1

You are setting it to the same value every time:

foreach (ListItem li in lstCatID.Items)
{
    if (li.Selected == true)
    {
       // you are always using lstCatID.SelectedItem.Value.
        CatID += lstCatID.SelectedItem.Value + ",";
    }
}

When you actually want the value of the item in your loop that is selected:

foreach (ListItem li in lstCatID.Items)
{
    if (li.Selected == true)
    {
        // get the value of the item in your loop
        CatID += li.Value + ",";
    }
}