Double-Buffering Exception

[Dave Veeneman]

I'm drawing a graphic directly to a form, using a Paint event handler. All
works well, except that the graphic flickers when I resize the form. So, I
implement double-buffering for the form using the following function:

public void EnableDoubleBuf fering()
{
this.SetStyle(C ontrolStyles.Us erPaint, true);
this.SetStyle(C ontrolStyles.Al lPaintingInWmPa int, true);
this.SetStyle(C ontrolStyles.Do ubleBuffer, true);
this.UpdateStyl es();
}

I call the function from the form's constructor, and I get an
ArgumentExcepti on saying that an invalid parameter was used.. The call stack
indicates the exception is thrown in the System.Drawing library.

The code runs fine if I disable the EnableDoubleBuf fering() call, but of
course I still have flicker.

Am I missing something here? Any help figuring this out is much appreciated.

Dave Veeneman
Chicago

[Val Savvateev]

Re: Double-Buffering Exception

At what line are you getting the exception? I'm using double buffering in
one of my controls too. The order is a little bit different -
this.SetStyle(C ontrolStyles.Al lPaintingInWmPa int, true);

this.SetStyle(C ontrolStyles.Us erPaint, true);

this.SetStyle(C ontrolStyles.Do ubleBuffer, true);



I think your problem is that you call UpdateStyles method (I don't) - it has
a bit different purpose (it updates other kind of styles).



"Dave Veeneman" <nospam@nospam. com> wrote in message
news:O%23VIXWXV DHA.1316@TK2MSF TNGP12.phx.gbl. ..[color=blue]
> I'm drawing a graphic directly to a form, using a Paint event handler. All
> works well, except that the graphic flickers when I resize the form. So, I
> implement double-buffering for the form using the following function:
>
> public void EnableDoubleBuf fering()
> {
> this.SetStyle(C ontrolStyles.Us erPaint, true);
> this.SetStyle(C ontrolStyles.Al lPaintingInWmPa int, true);
> this.SetStyle(C ontrolStyles.Do ubleBuffer, true);
> this.UpdateStyl es();
> }
>
> I call the function from the form's constructor, and I get an
> ArgumentExcepti on saying that an invalid parameter was used.. The call[/color]
stack[color=blue]
> indicates the exception is thrown in the System.Drawing library.
>
> The code runs fine if I disable the EnableDoubleBuf fering() call, but of
> course I still have flicker.
>
> Am I missing something here? Any help figuring this out is much[/color]
appreciated.[color=blue]
>
> Dave Veeneman
> Chicago
>
>[/color]

[Dave Veeneman]

Re: Double-Buffering Exception

Thanks! I'll give that a try.

For the benefit of anyone else reading this posting-- the code I originally
used came from the DotNet SDK documentation, which means the example in that
documentation may not work correctly.

--
Dave Veeneman
Chicago

[Piers Lawson]

Double-Buffering Exception

Did you ever find a solution? I get the same exception,
though I'm using slightly different styles:

DoubleBuffer, AllPaintingInWm Paint, UserPaint, Opaque
ResizeRedraw.

I get the exception:

System.Argument Exception: Invalid parameter used.

By dropping the AllPaintingInWm Paint the problem went
away, but of course my flicker returns.

Piers

[Piers Lawson]

Double-Buffering Exception

I just looked through the call exception stack and noticed
Dispose was in there. At the end of my OnPaint method I
have been calling e.Graphics.Disp ose(). I removed this
line an evrything started working!

I guess with double buffering on you shouldn't Dispose of
the graphics surface?

Piers

[Dave Veeneman]

Re: Double-Buffering Exception

Isn't that odd? Thanks!

"Piers Lawson" <PiersDROPTHIS@ gibber.freeserv e.co.uk> wrote in message
news:5ad401c357 6c$8c262360$a00 1280a@phx.gbl.. .[color=blue]
> I just looked through the call exception stack and noticed
> Dispose was in there. At the end of my OnPaint method I
> have been calling e.Graphics.Disp ose(). I removed this
> line an evrything started working!
>
> I guess with double buffering on you shouldn't Dispose of
> the graphics surface?
>
> Piers[/color]

[Dave Veeneman]

Re: Double-Buffering Exception

Isn't that odd? Thanks!

"Piers Lawson" <PiersDROPTHIS@ gibber.freeserv e.co.uk> wrote in message
news:5ad401c357 6c$8c262360$a00 1280a@phx.gbl.. .[color=blue]
> I just looked through the call exception stack and noticed
> Dispose was in there. At the end of my OnPaint method I
> have been calling e.Graphics.Disp ose(). I removed this
> line an evrything started working!
>
> I guess with double buffering on you shouldn't Dispose of
> the graphics surface?
>
> Piers[/color]