Updating ListView items in realtime. how?

[Ruth Ivimey Cook]

Hi folks, Background: I am creating a control using VS2005 .NET Framework that reports on the progress of some background processes. There is no concept of data entry or selection here; the only user action is to scroll the list if required. The current implementation of this uses a ListBox-derived control with drawing code implemented in the DrawItem event handler. That code works (more or less) fine when the data that backs each item in the list is static. I have two items that change dynamically: a progress bar and a text field that must be able to change fairly quickly over time. The current implementation includes custom drawing code for the whole - there are no child controls. My problem is that although I can change the value of the data field easily enough, all I can think of doing to make the ListBox aware of the change is to call Invalidate() for the whole control, and the paint events don't keep up, and the resulting effect is very jerky - tending in fact towards only updating once the progress reaches 100% The reason for a global Invalidate is that I am not aware of anything in ListBox that enables me to discover where an individual item is on screen, so I can't paint it explicitly or do a bounded invalidate. I am wondering if ListView offers that ability, but can't see it if that's so. So, to put the question straight: With an owner drawn list box/view, how to I tell the control that a (sub)item must be repainted now - preferably this instant - because the data backing it has changed? Regards Ruth Ruth Ivimey-Cook VS2005 / C# & VB

[Robert Rohde]

The ListBox has a public GetItemRectangle[^] function which will tell you the bounds. You could put this one into the Invalidate call.

[Ruth Ivimey Cook]

I eventually solved the problem using the List View SubItem Bounds property, which returns the bounds of the specific SubItem. I check that the bounds are contained by the parent's ClientRectangle, to avoid invalidate calls for items that are invisible, then pass the Bounds into the Invalidate call as Robert suggested. This is still slightly flickery, but not too bad. Thanks. Ruth Ivimey-Cook VS2005 / C# & VB