Code extract :
TimeSpan DayDifference = Convert.ToDateTime("2009-1-7").Subtract(Convert.ToDateTime("2009-1-1"));
To find the difference of the days, here we have used Subtract method. The Subtract method does not take start date into consideration. Hence, to get the exact number of days for the date range we need to add one more day to the result.
Response.Write("Number of Days : " + DayDifference.Days+1);