Moving items in a CheckedListBox

Posted by Marcus Hammarberg on February 20, 2008
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This is a very common requirement in applications and one that i always need to think a few extra minutes (hours, if you want) before i get it.

The GUI contains a CheckedListBox (or any other list) and the user want to be able to move the items up and down in the list. Yes i know - it seems trivial at first...

Here is one solution that uses a single method that is called with a parameter to indicate if the item is to be moved up or down.


'''
''' Moves an item in the listbox
'''

Private Sub MoveItemInListbox(ByVal up As Boolean)
' Check that something is selected
If chklst.SelectedItem Is Nothing Then
MessageBox.Show("Nothing selected")
Exit Sub
End If

' No flicker - on
chklstStycken.BeginUpdate()

' Remember the selected stuff, index, the item itself and if the item is
' checked or not
Dim selectedIndex As Integer = chklst.SelectedIndex
Dim selectedItem As Object = chklst.SelectedItem
Dim checked As Boolean = chklst.GetItemChecked(selectedIndex)

' Remove the item
chklst.Items.RemoveAt(selectedIndex)

' Calculate the new index
Dim newIndex As Integer = selectedIndex
If up Then
newIndex = newIndex - 1
Else
newIndex = newIndex + 1
End If

' Check that the index is within our bounds
If nyttIndex > chklstStycken.Items.Count - 1 Or nyttIndex < 0 Then
Exit Sub
End If

' Put the item back in the list and check it if needed
chklst.Items.Insert(newIndex , selectedItem)
chklst.SetItemChecked(newIndex , checked)

' Set focus on the moved item
chklstStycken.SelectedIndex = newIndex
chklstStycken.EndUpdate()
end sub



Yeah - i've ripped the solution from http://www.msnewsgroups.net/group/microsoft.public.dotnet.languages.csharp/topic21474.aspx, if you don't trust me.

Published by Marcus Hammarberg on Last updated