Silverlight Binding Linear Order

I stumbled across this Silverlight “feature” today. Silverlight’s binding works in a linear order.

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<ComboBox SelectedValue="{Binding SelectedHour, Mode=TwoWay}" ItemsSource="{Binding Hours}" />

In the above code, selected value isn’t being set on page load. When I change the ComboBox my SelectedHour ViewModel property was being updated with a new value. This let me know that my binding is working. In further debugging I noticed SelectedHour property was being accessed before the Hours property. The binding was trying to set the selected value but the ComboBox was ignoring it because it didn’t have any values. For fun I tired moving ItemSource binding in front of the SelectedValue binding.

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<ComboBox ItemsSource="{Binding Hours}" SelectedValue="{Binding SelectedHour, Mode=TwoWay}" />

Everything started working perfectly. Now I know to watch the order of my XAML properties in Silverlight.

I began programming in C++ when I was in college. Odd for a business major, but hey I am a Dork. After college I got a job as System Administrator. As a System Administrator I was in charge of web administration. My journey as a PHP web developer had begun. Since that time I have gained an in depth knowledge of CSS, Javascript, XML and MySQL. With changes and advances to technology I have also began learning AJAX. I started Blue Fire Development to do freelance work in my spare time.

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