Getting value of "System.Windows.Controls.TextBlock" when binding to Silverlight ComboBox

I'm attempting to use a Silverlight ComboBox with a static list of elements in a very simple binding scenario. The problem is the selected item is not returning me the Text of the TextBlock within the ComboBox and is instead returning "System.Windows.Controls.TextBlock".

My XAML is:

<ComboBo开发者_如何学Pythonx SelectedValue="{Binding Country, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}">
    <TextBlock FontSize="11" Text="Afghanistan" />
    <TextBlock FontSize="11" Text="Albania" />
    <TextBlock FontSize="11" Text="Algeria" /> 
</ComboBox>

In my C# file I'm binding to the ComboBox using:

Customer customer = new Customer() { Country = "Albania" };
DataContext = customer;

The binding does not result in Albania as the selected country and updating the ComboBox choice results in the Country being set to "System.Windows.Controls.TextBlock". I've tried fiddling around with DisplayMemberPath and SelectedValuePath but haven't found the answer. I suspect it's something really simple I'm missing.

---

Changing the ComboBox items to strings works. I'm not sure how you'd go about handling the case where TextBlocks were required for formatting...

<ComboBox SelectedValue="{Binding Country, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}">
    <System:String>Afghanistan</System:String>
    <System:String>Albania</System:String>
    <System:String>Algeria</System:String>
</ComboBox>