got the solution on the telerik-forum:
An easy and convenient way of achieving such functionality would be using the RadScheduler TimeSlotCreated server-side event and apply a css class to all time slot objects associated with a specific date as shown in the code snippet below:
Markup code:
<telerik:RadScheduler runat="server" ID="RadScheduler1" OnTimeSlotCreated="RadScheduler1_TimeSlotCreated"></telerik:RadScheduler>
Code behind:
protected void RadScheduler1_TimeSlotCreated(object sender, TimeSlotCreatedEventArgs e)
{
if (RadScheduler1.SelectedView == SchedulerViewType.WeekView)
{
if (e.TimeSlot.Start.Date.Day == 23 )
{
e.TimeSlot.CssClass = "red";
}
}
}
css code:
<style type="text/css">
html .RadScheduler .red {
background: red;
}
</style>
Special thanks to Boyan Dimitrov of Telerik