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ListView Filicker

Hi,

I have a ListView, often when I add a row to the view
(theListView.ListItems.add ...) the whole listview seems to be redrawn (Column headers and all!).  The end result is that it looks really bad as there is so much redrawing and flickering going on.  The sorted property is not enabled.

Any Ideas?  Is this supposed to happen?

Thanks,

Kevin
0
KevinG
Asked:
KevinG
1 Solution
 
MirkwoodCommented:
Do you use the refresh command or send the ListView_RedrawItems message?
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KevinGAuthor Commented:
Hi,

I am simply calling :

    Set itm = theFailView.ListItems.Add(, , location, 1, 1)

Every time this is called the whole listview is beign redrawed (including the ColumnHeaders).

Bye,

Kevin
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amebaCommented:
'Declarations
Private Declare Function SendMessage Lib "user32" Alias _
"SendMessageA" (ByVal hWnd As Long, ByVal wMsg As Long, _
ByVal wParam As Long, lParam As Long) As Long
Private Const WM_SETREDRAW = &HB
Private Const REDRAWOFF              As Long = 0
Private Const REDRAWON               As Long = 1

'Use this in your LoadListViev procedure:
    ' disable repainting
    Call SendMessage(hWnd, WM_SETREDRAW, REDRAWOFF, 0&)
    ' now add items to your listview
    ...
    ' enable repainting
    Call SendMessage(hWnd, WM_SETREDRAW, REDRAWON, 0&)
' Point-back guaranty:
' If this flickers, I guaranty return of your points
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amebaCommented:
But, this is not all.
After setting redrawon, you can use:
1. ListView.Refresh
2. Nothing, since next line will do refresh (e.g. setting Sorted property)
3. best
I am using sometimes:
Private Declare Sub InvalidateRect Lib "user32" _
(ByVal hWnd As Long, ByVal t As Long, ByVal bErase As Long)

    Call InvalidateRect(Ctl.hWnd, 0&, 0&)
' and my forms.ClipControls is set to False

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geonasCommented:
You can also use the LockWindowUpdate API as following:

1- Add the following declaration:

#If Win16 Then
    Declare Function LockWindowUpdate Lib _
        "User" (ByVal hWndLock As Integer) As Integer
#Else
    Declare Function LockWindowUpdate Lib _
        "user32" (ByVal hWndLock As Long) As Long
#End if

2- The hWndLock variable refers to the hWnd property of the form where you don't want to have screen updates shown. When you reissue the LockWindowUpdate with a value of 0 for hWndLock, you'll free up the screen and all updates will be shown instantly:

Dim lErr As Long
Dim x as Integer

'No ListView flicker, it will appear blank for
'just a moment...
Screen.MousePointer = vbHourglass
lErr = LockWindowUpdate(Me.hWnd)

For x=1 to 5000
    Set itm = theFailView.ListItems.Add(, , location, 1, 1)
    'Do whatever with itm
Next

'Now all the information is there
lErr = LockWindowUpdate(0)
Screen.MousePointer = vbDefault

Hope this will answer your question,

Regards
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