Remove many Date in WPF Datepicker

Question

Goal:
I want to blackout all dates before start date and after end date.

The user shall only select between start and end date in the WPF datepicker.

Problem:
I have seen that you have to make manual work to write specific date to blackout a date. I do not know how to make it when you have lots of date. I'am are talking 'bout removing all dates in 2011 ,2012 etc.

Information:
The data of start date and end date is dynamically. They will interchangeably.