The viewmodel Proptery should look like this I was fighting with this issue for a while. To String())); private Key Type _Selected Key = new Key Type(); public Key Type Selected Key #endregion Selected Key I had this problem with a Combo Box displaying a list of colors ( List ).In my case I was using in complex type (List) as the Item Source and was using a Key Type as the selected value. Selecting a color was possible but it wasnt displayed when the selection closed (although the property was changed!
In order to avoid that use the Keep Alive property of your pages.
This will result in only the Loaded event being fired when navigating back to a page you have already visited.
The second step is to let our custom User class implement the INotify Property Changed interface.
By doing that, our User objects are capable of alerting the UI layer of changes to its properties.
I'm not sure if this is just an issue with the way the Combo Box and MVVM pattern works. I have had similar issues and it was solved by making sure I was implementing IEquatable properly.
When the binding occurs, it is trying to see if the objects match so make sure you are properly implementing your equality checking.
Example: I have noticed this behavior before as well.
I have noticed that the Selected Index property doesn't cause the same bug.
What seems to be the issue is that the Selected Value/Selected Item is occurring before the Item source is finished loading.