The ObservableCollection (or any collection that implements ICollectionChange) exposes an event (CollectionChanged) and the Databinding will subscribe to this to monitor changes in the collection, when one occur it will cause the control to refresh it's datasource.
This is similar to objects that implement INotifyPropertyChange, those will expose a PropertyChanged event that will trigger an update in the UI whenever the control value of the property changed (or more precisely when the event is fired) Miguel A. Madero Reyes <http://www.miguelmadero.com/> www.miguelmadero.com (blog) <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED] +61 (0) 406-704-161 623/243 Pyrmont Street Pyrmont, NSW, 2009 Australia P "Please reconsider your environmental responsibility before printing this e-mail" The information in this e-mail is confidential and may be legally privileged. It is intended solely for the addressee. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Muhammad Niaz Sent: Saturday, 1 November 2008 10:58 PM To: listserver@ozSilverlight.com Subject: [OzSilverlight] SL Combobox problem.? Hi All, I have a Combobox in SL App when I remove item from the collection (ObservableCollection<UserDTO>/List< UserDTO >) work fine, but the issue that Combobox not update its items-Containing area when its bind with ObservableCollection, mean if there were 4 items in Combobox then will remain 3 but total space of items-Containing remain 4. And but when its bind to List<> then it only delete the item from collection but not from Combobox area, mean if there were 4 items in Combobox then will remain even 4. why, here is some code: XAML: <ComboBox x:Name="ddlUser" Canvas.ZIndex="2" Grid.Row="0" Grid.Column="1" DisplayMemberPath="name" ToolTipService.ToolTip="Select user." Style="{StaticResource NormalDropDownListStyle}" /> CS: private ObservableCollection<UserDTO> resultUserDTO = new ObservableCollection<UserDTO>(); private List<UserDTO> resultUserDTO = new List<UserDTO>(); also why should I use List<> over ObservableCollection.? Enen though I call this like, ddlUser.UpdateLayout(); ddlUser.SelectedItem = innerUserDTO; Thanks & Regards, Muhammad Niaz Software Engineer Intagleo Systems Pvt Ltd www.intagleo.co.uk ------------------------------------------------------------------- OzSilverlight.com - to unsubscribe from this list, send a message back to the list with 'unsubscribe' as the subject. Powered by mailenable.com - List managed by www.readify.net ------------------------------------------------------------------- OzSilverlight.com - to unsubscribe from this list, send a message back to the list with 'unsubscribe' as the subject. Powered by mailenable.com - List managed by www.readify.net