Date validation against data table

Question

i am re-writing a reservation system in MVC5 using C#.  New to both.  in the DB i have a table of blackout dates. the site owner enters records in the blackout table to exclude them from selection by the visitor.   structure id startdate enddate    use case (currently) visitor enters their arrival date system returns the count of the entered date being between an any of the  start and end dates in the blackout table and returns validation message if the count is > 0    what is the best approach to creating this validation routine in the MVC create form? TIA

George Benson · Answer

i guess i'm not being clear ... (not unusual for me!) in the create view  validation i need to test the entered date value against the records in the Blackout Dates table.   I originally did this with a javascript ajax call but how would i accomplish in C#?

Jaish Mathews · Answer

You might be asking the days between 2 dates and with that understanding, you always use TimeSpan to store date difference. Like below, TimeSpan has many useful properties.
DateTime d1 = new DateTime(2019,02,03);
DateTime d2 = new DateTime(2019, 02, 10);
TimeSpan dateDiff = d2 - d1;
int days = dateDiff.Days;