EnableVisualSty les and DoEvents

[Lance]

I've noticed that calling DoEvents is much slower in an application that has called Application.Ena bleVisualStyles in Sub Main. Furthermore, the performance seems to worsen each time that DoEvents is called.

To demonstrate what I'm experiencing, create an app with a Sub Main, a Main Form, and a Button (called Button1). Include the following code in Sub Main:

Application.Ena bleVisualStyles
Application.DoE vents
Application.Run (New MainForm)

Now, include the following code in the Click event handler of Button1:

For i As Integer = 1 to 8000
Application.DoE vents
Next i

On my system the first time that I click Button1 takes ~0.92 seconds. Subsequent clicks take 1.35, 1.73, 2.12, and 2.52 seconds. But, if I now remove Application.Ena bleVisualStyles from Sub Main, then clicking Button1 only takes ~0.07 seconds (and the time does not increase if I continue to click Button1).

Is this a known issue? Is there a fix? Would it help to enable visual styles via a manifest file rather than calling EnableVisualSty les?

I'm using .NET Framework v1.1 on Windows XP Pro (SP1).

Thanks,
Lance

[Jay B. Harlow [MVP - Outlook]]

Lance,

I thought that this technique was faily common. Am I wrong? Its fairly common in VB6. However! you are in VB.NET now! ;-)
Is there a better way? In VB.NET I would use a Thread or the Application.Idl e event to run the long
process. (I would favor a Thread over Application.Idl e, mostly becuase a
Thread is easier).

http://msdn.microsoft.com/library/de...dComponent.asp

Review that entire section of MSDN.

Hope this helps
Jay

"Lance" <zi***@hotmail. com> wrote in message
news:36******** *************** ***********@mic rosoft.com... Thanks for the example!

The reason for my interest is when DoEvents is called from within a long loop in order for an app to respond to the user while the loop is executing.
I thought that this technique was faily common. Am I wrong? Is there a
better way? If not, then it seems to me that in this case having DoEvents
take 13+ times longer can be an issue, depending on the size and structure
of the loops.
Thanks again,
Lance

[Jay B. Harlow [MVP - Outlook]]

For those of you looking at Whidbey (VS.NET 2004), I found this class which
should simplify adding Threading to a Windows Forms application!

http://longhorn.msdn.microsoft.com/l...undworker.aspx

Jay

"Jay B. Harlow [MVP - Outlook]" <Ja************ @msn.com> wrote in message
news:eP******** ******@TK2MSFTN GP11.phx.gbl...

Lance,

I thought that this technique was faily common. Am I wrong? Its fairly common in VB6. However! you are in VB.NET now! ;-)

Is there a better way?

In VB.NET I would use a Thread or the Application.Idl e event to run the

long process. (I would favor a Thread over Application.Idl e, mostly becuase a
Thread is easier).

http://msdn.microsoft.com/library/de...dComponent.asp
Review that entire section of MSDN.

Hope this helps
Jay

"Lance" <zi***@hotmail. com> wrote in message
news:36******** *************** ***********@mic rosoft.com...

Thanks for the example!

The reason for my interest is when DoEvents is called from within a long loop in order for an app to respond to the user while the loop is

executing. I thought that this technique was faily common. Am I wrong? Is there a
better way? If not, then it seems to me that in this case having DoEvents
take 13+ times longer can be an issue, depending on the size and structure
of the loops.

Thanks again,
Lance

[Peter Huang]

Hi Lance,

Thanks for your quickly reply!

I can reproduce the behavior. Also I have reported it to our product group,
I will get back with more information here ASAP.

Thank you for your understanding.

Best regards,

Peter Huang
Microsoft Online Partner Support

Get Secure! - www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.

[Lance]

Thanks for the links!

[Lance]

Wow! BackgroundWorke r looks awesome! Now you really have to tell me how to get Whidbey :)

[Jay B. Harlow [MVP - Outlook]]

Lance,
Call MSDN customer support and ask for it.

http://msdn.microsoft.com/Longhorn/S...ng_GetLonghorn

Of course this means that you need to an MSDN subscriber.

Note the PDC version of Whidbey is an alpha/Technology Preview version. I
have not seen anything on getting on the Whidbey Beta yet.

Hope this helps
Jay

"Lance" <zi***@hotmail. com> wrote in message
news:01******** *************** ***********@mic rosoft.com...

Wow! BackgroundWorke r looks awesome! Now you really have to tell me how to get Whidbey :).

[Lance]

Thanks.

[Lance]

Thanks a lot for the info!