vb screen flicker problem

[zafar1]

i am using dynachart activex on a form. when the chart is refreshed the whole form flicker.

zafar

[Thomas Stockwell]

Is DoubleBuffer active on the form. in .NET 1.1 you can use the SetStyle command. If you use .NET 2.0 you can use SetStyle and/or the DoubleBuffer property. Either of these two ideas might help with the form flickering. Another possibility would be to see if the activeX has a refresh event and set a handler for the event that will also refresh the form before the flicker.

Regards, Thomas Stockwell Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning. Visit my homepage Oracle Studios[^]

[zafar1]

Thanks thomas I am actually working on vb6 is there any thing i can do. regards zafar

zafar

[gisTimmy]

The Windows API call for LockWindowUpdate will control your form flickering when you do a lot of updates to controls. In a code module, put this in your declaration section:

Declare Function LockWindowUpdate Lib "user32" \_
    (ByVal hWnd As Long) As Long

Then add this Sub to the same module.

Public Sub LockWindow(hWnd As Long, blnValue As Boolean)
    If blnValue Then
        LockWindowUpdate hWnd
    Else
        LockWindowUpdate 0
    End If
End Sub

When you are about to update the chart, call LockWindowUpdate:

'	Lock the form's window to prevent refresh
LockWindowUpdate Me.hWnd, True
'	Do your thing with the chart...
'	Unlock the window to show the updated form
LockWindowUpdate 0, False

I haven't tried this with chart controls, but it works OK with TreeViews and ListViews. ---------------------------------------------------------------------------------------------------

"It may not be rocket science, but then rocket science produced Apollo 13."

- GIS Timmy!?