a loading screen for a c# wpf listbox

Question

I'm using a list box where there are on average about 500 thumbnails (items) that can be sorted and searched.

Since I'm using default databinding and search descriptors (which I've heard are slow due to reflection) the list takes a noticeable pause of a few seconds loading, sorting, and searching (the list dynamically updates based on the contents of the search box so the first one or two letters typed are really slow).

I don't think I can fully do away with reflection give the timeframe for the project, and speed isn't super essential, but I'd like some kind of graphical indication of the delay so it doesn't confuse the user. How could I do something like a website video loading screen where the listbox grays out and some kind of loading circle indicates it's processing until the list is ready? Or even just grayed out with the words "Loading..." for a few seconds could work. Any ideas?

Thanks in advance for your help and suggestions!!!

Answer 1

Silverlight-Controlkit comes with a very handy "busyindicator"-control... too bad there seems to be no such thing for WPF by default.

But I found this seemfully comparable control for you: http://sweux.com/blogs/pombeiro/index.php/2009/12/01/a-busy-state-indicator-attached-behavior/

download-source: http://gallery.expression.microsoft.com/en-us/BusyIndicator

Answer 2

Try BackgroundWorker

Use the DoWork method to update your list dynamically based on the search keyword Use the ProgressChanged method to update your UI with some animation saying 'Loading'. A ProgressBar could be used

Use Dispatcher to access your list inside the DoWork method

Answer 3

Like Veer wrote, BackgroundWorker is probably your best bet.

For the graphical indication of progress and/or delay, take a look at

http://www.codeproject.com/KB/WPF/WPF_Loading_Wait_Adorner.aspx

It looks like pretty much exactly what you want to do.