Screen flickering

Question

Hi,

I have a program with 2 forms.when 2nd form activates there is flickeing.

what to do to avoid screen flickering?

(application.screen updating=false) not workiing

plz help

kuttu7

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kuttu7

Answer 1

Hi Kuttu,

Welcome to the MSDN Forum.

Please just try to make two very simple forms to test this scenario. If it is still flicker, there should be something with your computer and nothing to do with your code, and then you can try this forum: http://answers.microsoft.com/en-us 

If it is still flickering, so please post the related code here, I will try to help you out.

Best regards,

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Mike Feng
MSDN Community Support | Feedback to us
Please remember to mark the replies as answers if they help and unmark them if they provide no help.

Answer 2

Visual Studio will suggest that DoubleBuffering your form and controls will eliminate screen flicker.  It will, but not as easily as you might wish.  Just setting the form’s “DoubleBuffered” property to “True” may not be enough.  Eventually, I put the following together using ideas from various internet sources.

If needed, the sub “Stop_Flicker” can be called by every form in your project resulting in every control being fully “DoubledBuffered”.  If you add controls to your form, not to worry, they will be noted and processed.  If you have a control that has particularly heavy 3M (manipulation, modification and movement) activities, using “.SuspendLayout” and “.ResumeLayout” is a good idea.

Note:  The routine “Stop_Flicker” is recursive and it needs a “stop” or “escape” procedure to prevent potential stack overflow problems.  This simple “escape” should be tailored to particular situations.

Option Strict On

ImportsSystem.Drawing

ImportsSystem.Reflection

PublicClassForm1

PrivateSubBuffer(cnlWhat As Control)

   Dimtype As Type = cnlWhat.[GetType]()

   Dimparam As Object() = {ControlStyles.AllPaintingInWmPaint Or _

                            ControlStyles.UserPaint Or ControlStyles.DoubleBuffer, True}

   Dimflags As BindingFlags = BindingFlags.NonPublic Or BindingFlags.Instance

   Dimmethod As MethodInfo = type.GetMethod("SetStyle", flags)

   Try

     Ifmethod IsNot Nothing Then

        method.Invoke(cnlWhat, param)

      EndIf

   Catchex As Exception

      MsgBox(ex.Message, , cnlWhat.Name)   ' todo    send to error routine

   EndTry

 EndSub

PrivateSubStop_Flicker(cnlTarget As Control)

   StaticintFlikcount As Integer = 0       ' count for escape routine

        CallBuffer(cnlTarget)

        intFlikcount += 1

        IfintFlikcount < 999 Then

            IfcnlTarget.Controls.Count > 0 Then

                ForEachmyControl As Control In cnlTarget.Controls

                    CallStop_Flicker(myControl)

                Next

            EndIf

        EndIf

EndSub

PrivateSubForm1_Load(sender As System.Object, e As System.EventArgs) _

   Handles MyBase.Load

   CallStop_Flicker(Me)

EndSub

If you wish to examine the results in more detail, insert (modify) and use where needed:

   method = type.GetMethod("GetStyle", flags)

   param  = {ControlStyles.AllPaintingInWmPaint Or _

             ControlStyles.UserPaint Or ControlStyles.DoubleBuffer}

   MsgBox(method.Invoke(cnlWhat, param).ToString, , cnlWhat.Name)