Why this UWP ComboBox can be blank after initialization but works fine for selection?

Question

I have a ComboBox like this

Answer 1

It's blank because you don't have anything selected in the first place. If I'm not mistaken, you have to either use SelectedItem to bind your selection or SelectedValue with SelectedValuePath.

I actually never use SelectedValue with SelectedValuePath myself, so after initializing collection of items which ComboBox.ItemSource will be binded to - for example ObservableCollection Persons {get; set;} - I also set selected item property Person SelectedPerson {get; set;} to one of the values from collection. Then I bind ComboBox.SelectedItem to this property, so on initialization it shows predefined selected value.

I guess you can achieve the same with SelectedValue and SelectedValuePath, but you have to use them together as described here.