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?

Answer 1

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]];
        }

Answer 2

try using this code I created using VB.NET :

Public Shared Function getSelectedValuesFromListBox(ByVal objListBox As ListBox) As String
    Dim listOfIndices As List(Of Integer) = objListBox.GetSelectedIndices().ToList()
    Dim values As String = String.Empty

    For Each indice As Integer In listOfIndices
        values &= "," & objListBox.Items(indice).Value
    Next indice
    If Not String.IsNullOrEmpty(values) Then
        values = values.Substring(1)
    End If
    Return values
End Function

I hope it helps.

Answer 3

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);