[RESOLVED] ListBox question

[el84]

Hi

I am trying to arrange a listbox so that as each individual line is entered (happens to be a list of files harvested from a directory one by one) then the earliest item displayed pops off the top, so that the latest items.add is always showing.

I did this with vb6 by default as far as I can see. How in 2010 please?

[.paul.]

to always add the new item at the top of the listbox:

ListBox1.Items.Insert(0, "new item")

[el84]

Thanks, but I want to add items at the foot and *have the earlier items scroll off the top*

[MattP]

Have a look at the ListBox's TopIndex Property.

[.paul.]

this works:

ListBox1.Items.Add("new item")
Dim maxItems As Integer = ListBox1.Height \ ListBox1.GetItemHeight(0)
ListBox1.TopIndex = ListBox1.Items.Count - maxItems

[el84]

Hate to look a gift horse in the mouth, but isn't there a simpler way? What I am actually doing is showing in a list box the names of files I am copying from one drive to another, one by one as they get copied. I want to add each file to the foot and when the box is full, have the earliest files drop off the top, so that the latest file is always shown at the foot.

[.paul.]

maybe someone else knows a way, but that's my solution

[el84]

OK. Do I have to put those lines inside the loop as the routine loops through all the files (there could be hundreds) or I can I set it once?

[Shaggy Hiker]

There may be an easier way, but I don't know of an automatic way, which is probably what you are looking for. I don't know of a property setting that will cause the listbox to automatically scroll to the bottom.

[MattP]

this works:

ListBox1.Items.Add("new item")
Dim maxItems As Integer = ListBox1.Height \ ListBox1.GetItemHeight(0)
ListBox1.TopIndex = ListBox1.Items.Count - maxItems

You don't need to calculate the number of items that will fit in the ListBox.

Imports System.ComponentModel

Public Class Form1

    Dim MyBindingList As BindingList(Of String)

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        MyBindingList = New BindingList(Of String) From {"Item 1", "Item 2", "Item 3", "Item 4", "Item 5"}
        ItemsListBox.DataSource = MyBindingList
    End Sub

    Private Sub InsertButton_Click(sender As Object, e As EventArgs) Handles InsertButton.Click
        MyBindingList.Add("New Item")
        ItemsListBox.TopIndex = ItemsListBox.Items.Count - 1
    End Sub
End Class

[Shaggy Hiker]

I got distracted and got in a bit late.

The question you need to answer for yourself is: How do you want this to behave? After all, if you were to toss items into the listbox as fast as you obtained them, it is likely that the listbox will be pretty much a blur, as it will be scrolling by at a good clip most likely. That may not look good no matter what. Therefore, you might consider only adjusting the Listbox every N items, or so. Alternatively, you might want to only update on a timer, though that could get much more tricky. I think it comes down to the visual result that you want.

[el84]

I am not worried about any such limitation. I simply want to list the files from the earliest to the last as they copy, and I want the earliest to drop off the top when the listbox becomes full.

[dunfiddlin]

ListBox1.Items.Add(filename)
            ListBox1.SelectedIndex = ListBox1.Items.Count - 1

[el84]

Yep! That's it. Had just found it by Googling at length, and have been trying it. Just put that second line in after each item is added (ie in the loop). Thanks all!