Getting all selected values from an ASP ListBox

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);

use GetSelectedIndices method of listbox

  List<int> selecteds = listbox_cities.GetSelectedIndices().ToList();

        for (int i=0;i<selecteds.Count;i++)
        {
            ListItem l = listbox_cities.Items[selecteds[i]];
        }