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POWPF: What can cause a binding source to not be updated?
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copied!<p>I have a situation I'm not sure how to debug. I'm hoping someone can suggest why it might not be working and point me in the right direction.</p> <p>I have a TIFF image from a database which is exposed as a property of type <code>System.Data.Linq.Binary</code>. I want to display the individual frames from that TIFF image in an <code>ItemsControl</code> so I've written a converter that takes the Binary datatype and returns an <code>ObservableCollection</code> of BitmapFrames. I'm binding <code>ItemsControl.ItemsSource</code> to the Binary property using the converter along with <code>"Mode=TwoWay"</code> and <code>"UpdateSourceTrigger=PropertyChanged"</code>.</p> <p>The display of the images is working fine. The problem is that if I add a frame to the collection the display updates, but that change is not transferred back to the Binary property in the source object. The <code>ConvertBack()</code> method in my converter is never called (indicating to me that the binding is never even trying to update the source). If I manually make a call to <code>BindingExpression.UpdateSource()</code> as if it were set for <code>"UpdateSourceTrigger=Explicit"</code> the Binary property does update correctly.</p> <p>So if a binding is set for <code>"Mode=TwoWay"</code> and <code>"UpdateSourceTrigger=PropertyChanged"</code> and the object implements <code>INotifyPropertyChanged</code> (which <code>ObserverableCollection</code> does), why doesn't the binding actually try to update the source?</p> <p>Thanks!</p>

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