TomBecker.net

Monday, February 11, 2008

Moving items up or down in a listbox

So I really didn't think this was that complicated to do. Changing the order of items that are displayed in a standard list box. Nothing all that fancy. It being a Monday, I decided to try and not think and just to grab some code from somewhere on the internet.

I was surprised by the wide variety of different ways to do this and all of them seemed overly complicated. One involving a nested for loop or another messing with the data source and saying that it only worked when the box was bound. Craziness.

All of this seemed way to complicated. So I broke down and thought about it for a second, and came up with (I think) the easiest way to move an item up or down in a list box control in .Net.

'down button press
Private Sub btnDown_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnDown.Click


Dim index As Integer = Me.lbxSortOrder.SelectedIndex
Dim itemCount As Integer = Me.lbxSortOrder.Items.Count
Dim li As ListItem = Me.lbxSortOrder.Items(index)
Dim newIndex As Integer

If index = itemCount - 1 Then
   newIndex = index
Else
   newIndex = index + 1
End If

Me.lbxSortOrder.ClearSelection()
Me.lbxSortOrder.Items.Remove(li)
Me.lbxSortOrder.Items.Insert(newIndex, li)
li.Selected = True

End Sub

The up button press is the same exact thing except the text on the index needs to look like this:

   
If index = 0 Then
   newIndex = 0
Else
   newIndex = index - 1
End If

And thats it. I know it was simple, I thought about not posting this cause of its simplicity, but by looking what else was out there, I'll add my two cents.

Labels: .NET