c# - Getting all selected values from an ASP ListBox

Question

I have an ASP ListBox that has the SelectionMode set to "Multiple". Is there any way of retreiving ALL selected elements and not just the last one?

<asp:ListBox ID="lstCart" runat="server" Height="135px" Width="267px" SelectionMode="Multiple"></asp:ListBox>

Using lstCart.SelectedIndex just returns the last element (as expected). Is there something that will give me all selected?

Answer 1

You can use the ListBox.GetSelectedIndices method and loop over the results, then access each one via the items collection. Alternately, you can loop through all the items and check their Selected property.

// GetSelectedIndices
foreach (int i in ListBox1.GetSelectedIndices())
{
    // ListBox1.Items[i] ...
}

// Items collection
foreach (ListItem item in ListBox1.Items)
{
    if (item.Selected)
    {
        // item ...
    }
}

// LINQ over Items collection (must cast Items)
var query = from ListItem item in ListBox1.Items where item.Selected select item;
foreach (ListItem item in query)
{
    // item ...
}

// LINQ lambda syntax
var query = ListBox1.Items.Cast<ListItem>().Where(item => item.Selected);