Day/Week Event Calendar All Day Events with Exchange Web Services

You can use IsAllDayEvent property:

DataAllDayField = "IsAllDayEvent"

See also:
https://msdn.microsoft.com/en-us/library/microsoft.exchange.webservices.data.appointmentschema.isalldayevent(v=exchg.80).aspx

Thanks Dan!

I have tried that but I get the error "Property accessor 'IsAllDayEvent' on object 'Microsoft.Exchange.WebServices.Data.Appointment' threw the following exception:'You must load or assign this property before you can read its value.'"

Okay never mind, I just realized that the AppointmentSchema.IsAllDayEvent was not being loaded as a part of the CalendarView PropertySet. For those having this same issue using Exchange Web Services be sure to add AppointmentSchema.IsAllDayEvent to your CalendarView PropertySet when loading your appointments:

Dim calendar As CalendarFolder = FindDefaultCalendarFolder()

Dim cView As New CalendarView(startDate, endDate, 50)

cView.PropertySet = New PropertySet(AppointmentSchema.Subject, AppointmentSchema.Start, AppointmentSchema.End, AppointmentSchema.Id, AppointmentSchema.IsAllDayEvent) '<=== Make sure you add "AppointmentSchema.IsAllDayEvent"

Dim appointments As FindItemsResults(Of Appointment) = calendar.FindAppointments(cView)

Great, thanks for the update!