Fix the Combobox with selectedvalue property
The Silverlight 4 implementation is bug-ridden. As soon as the SelectedValue is bound to a null value at target the binding breaks and no longer works.
Another big issue is if the value for the ItemSource property changes after the SelectedValue is bound, then binding breaks again and the currently selected value is no longer displayed.
Refer to this link for a work around to both issues: http://forums.lhotka.net/forums/p/9786/46097.aspx
It is worth noting that this issue does not occur when binding with SelectedItem, only when using the new SelectedValue (and SelectedValuePath) implementation does the above issues come into play.
Please re-open in order to correct this behavior that is both very frustrating and time wasting.
Chris Anderson commented
Adding the SelectedValue and SelectedValuePath properties to the ComboBox controls is really important for business applications in Silverlight. We really need it to support foreign key scenarios where for example we have a property ModelID on an object bound to the DataContext, which relates to a preloaded list/dictionaries of models (each with an ID and description) that is bound to the ItemsSource property. This is really really needed for any serious business application.
Jack Bond commented
It would also be really nice if you could navigate the ComboBox items via the keyboard, i.e., if i click 'm' it would skip to the first item starting with m, and then on repeated click of 'm' it would scroll to the next 'm' item. What would be nice about this behavior is that it would make the Silverlight Combobox work like EVERY OTHER COMBO BOX EVER IMPLEMENTED!!!