MVP please help - ShowDialog() very slow

Tech-Archive recommends: Fix windows errors by optimizing your registry

Hi,

Development is done under XP SP2, C# .NET, Visual Studio .NET 2003, .NET
v1.1

I have a System.Windows.Form that displays a dialog when a button is
pressed.

The dialog has a list box, a text box used as a typing helper, and two
buttons in it.

The list box has approximately 50,000 items in it.

The first time the dialog is displayed it takes over 20 seconds, and even
subsequent calls to show it take almost as long (a mere 18-19 seconds), even
though the documentation says that any calls to ShowDialog() after the first
one are really only changing the visibility of the dialog.

In the Visual Studio debugger, it is the actual call to ShowDialog() that is
taking so long.

Task manager shows intense CPU activity during the 20 seconds, but little
memory activity.

With only a few thousand items there is no problem.

Once the dialog is displayed, I use a typing helper to scroll the list box
to different places; this all happens very quickly - no performance issues
at all once it is displayed.

Are there any callbacks that could be being invoked during ShowDialog() ?

Can anyone help?

Thanks in advance,
Chris Hough



.

Quantcast