Is there a way to block dates?

[MalinEbbesen]

Let's say there are no available appointments at certain dates, is there any way to let the user know this? Gray out certain dates or block them?

[ME-MarvinE]

Yes. The only way to customise a day is to set the DayTemplate property of the CalendarView. You can set this to a DataTemplate containing your own custom view, or you can use a DayView to replicate the existing look and functionality. The 'Customising a day' example in the sample app does this and would be useful to look at.

When using a DayView, the essential properties you need to set to replicate existing functionality are the IsSelected, IsToday, IsCurrentMonth, and IsInvalid properties. You can view more info of how these states work (at the bottom of the page) as well as all the properties in the DayView at the DayView Properties wiki page. The Event Calendar example in the sample app is also something you can reference for appointment-style DayViews.