Flicker free Listview

[selimsl]

Hi,
I am using Listview control on my project. I add items to the listview control cyclically. I mean I fill the listview with values and then after a time period I refill the listview with the new values. I do it with the code below. But everytime I refill listview it flickers. For example I drag scrollbar of listview down and when it flickers, scrollbar goes up to its default position.

The procedure below is called cyclically

        '******************************
        Dim intIndex As UInt16 = intStartingAddress
        '******************************
        'Clear Listview
        lvwDisplayData.Items.Clear()
        '******************************
        For Each intTemp As UInt16 In intArray
            'Declare a ListViewItem Object
            Dim objListViewItem As New ListViewItem
            'Set the Properties of the ListViewItem Object
            objListViewItem.Text = intIndex.ToString
            objListViewItem.SubItems.Add(intTemp.ToString)
            'Add the ListViewItem Object to the ListView
            lvwDisplayData.Items.Add(objListViewItem)
            intIndex += 1
        Next
        '******************************

 

[ousoonerjoe]

Take a look at the following. It will cause the control to stop refreshing then once fully loaded you can turn it back on:

			lstDetail.BeginUpdate()
			'For Loop
			'    do code stuff.
			'Next
			lstDetail.EndUpdate()

--------------------------------------------------
Stubbornness is a virtue -- if you are right. --Chuck Noll
--------------------------------------------------

 

[selimsl]

Dear ousoonerjoe ,

I applied your suggestion on my code, but unfortunately it didn't work.

On the web I found same thread, they said DoubleBuffered solved this issue, but I don't know how to apply it on my code.

 

[selimsl]

the link of the thread

http://www.vbforums.com/showthread.php?t=342255

 

[selimsl]

The problem with my code is listview.items.clear()

I have created a form that uses ListView. How do I clear the contents of the listview so that I can update the data?
If I use clear keyword this causes strange behaviour I mentioned before.

 

[jebenson]

Well, the link you posted does have an answer:

Public Class ffListView
Inherits ListView

Public Sub New()
Me.DoubleBuffered = True
End Sub
End Class

They way you would use this is to create a new class in your project, then copy this code into the class. Next, open the <formname>.designer.vb file and in it find the line that declares the listview in question. It will look something like this:

Me.ListView1 = New System.Windows.Forms.ListView

Change it to this:

Me.ListView1 = New ffListView

That should be all you need. Post back and lets us know how it goes.



I used to rock and roll every night and party every day. Then it was every other day. Now I'm lucky if I can find 30 minutes a week in which to get funky. - Homer Simpson

Arrrr, mateys! Ye needs ta be preparin' yerselves fer Talk Like a Pirate Day!

 

[selimsl]

When I use ffListView Class nothing can be read from listview. I mean I added 30 rows to the listview but nothing can be read on the listview. I checked items.count property and it says count=30.

Instead of this I changed the code which was post with the code below

        '******************************
        Dim intIndex As UInt16 = 0
        '******************************
        'lvwDisplayData.BeginUpdate()
        '******************************
        For Each intTemp As UInt16 In intArray
            'Add the ListViewItem Object to the ListView
            lvwDisplayData.Items(intIndex).SubItems(1).Text = intTemp.ToString
            intIndex += 1
        Next
        '******************************
        'lvwDisplayData.EndUpdate()
        '******************************

By doing this I gave up using clear keyword and I edit rows directly with SubItems(1).Text keyword. Now scrollbar doesn't go up automatically and I can select any row. About flicker, there is still little flicker, but not so much as before. I think it is normal, isn't ?
By the way this procedure is called approximately every 300 msec.