Validate the selected value in a WPF combobox

Question

Like the title says, I am trying to validate my form, but I have an issue getting the combobox value:

Answer 1

Stupid, stupid stupid lack of observation on my part. If you were to change the ComboBox's Text to SelectedValue instead like so:

One will get the selected value and NOT the text.

For those of you who might want to read on it, I found the original tutorial here.

WPF TextBox Validation with IDataErrorInfo