Question

How to get the last selected item in a .Net Forms multiselect ListBox? Apparently if I select an item in the listbox and then select another 10 the selected item is the first one.

I would like to obtain the last element that I selected/deselected.

Answer 1

I would take this general approach:

Listen for the SelectedIndexChanged event and scan through the SelectedIndices collection every time.

Keep a separate list of all selected indices, appending ones that have not been in the list, removing those that have been de-selected.

The separate list will contain the indexes in the chronological order they were selected by the user. The last element always is the most recently selected index.

// for the sake of the example, I defined a single List<int> List<int> listBox1_selection = new List<int>();  private void listBox1_SelectedIndexChanged(object sender, EventArgs e) {     TrackSelectionChange((ListBox)sender, listBox1_selection); }  private void TrackSelectionChange(ListBox lb, List<int> selection) {     ListBox.SelectedIndexCollection sic = lb.SelectedIndices;     foreach (int index in sic)         if (!selection.Contains(index)) selection.Add(index);      foreach (int index in new List<int>(selection))         if (!sic.Contains(index)) selection.Remove(index); }