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Force update of bound combobox when validation changes bound source property

Posted By:      Posted Date: October 12, 2010    Points: 0   Category :WPF

.NET 3.5SP1, VS 2008

I have inherited a system for maintenance and I'm working my way through defect reports.  Once such issue involves insuring a combobox value is reset to a known good value when a validation failure occurs.  The combobox is bound to a source property loaded which is initialized when the user selects a case for update.  According to this post it is an issue inside of WPF to ignore value changes when processing an update to the source (at least that's how I interpret the post).  Unfortunately for me, the UpdateSourceTrigger for a combobox is PropertyChanged, so the suggested approach does not fit my needs.  I tried it anyway, just to be certain.

I've created a test app which mimics the application design and exhibits the behavior I'm attempting to work around.  At this point, I'm at a loss how to proceed further.  I'm certain there's something I'm missing and would appreciate a nudge in the proper direction.

xaml window:

<Window x:Class="TestWpf.ComboTest

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