date difference using datepicker in wpf

Question

Im trying to calculate the how many days there are between two dates and display the result in a textblock, i am using wpf. However i get a nullable object must have a value

Answer 1

If you want to get the selected date, you're using the wrong property. DisplayDateStart and DisplayDateEnd limits the possible choices. They are nullable because it should be possible to create a date picker without any limitations. Change your start and finish assignments to use the DisplayDate property instead:

DateTime start = datePicker1.DisplayDate.Date;
DateTime finish = datePicker2.DisplayDate.Date;

You should also consider renaming your datepickers. Having controls named datePicker1 and datePicker2 is typically hard to remember. What about datePickerStart and datePickerEnd?

(Disclaimer: I know that WPF controls typically don't get a name, because they are databound so the name won't matter, but in this case they are explicitly accessed and should have proper names).