Since you are using two pages, each needs its own WebscheduleInfo object
So when you open up your DayView Page - use a query string that contains the monthview's clicked date or that pages WebScheduleInfo's ActiveDay.
Then in the page load of your DayView page - retreive the query string and set the DayView's WebscheduleInfo's ActiveDay property.
Here is a help link to the WebScheduleInfo's ActivDayUtc property:
Here is a help link on setting the active day: