In RadTreeView control if we click on parent node with out expanding its children then in OnClientNodeChecked event its showing children nodes count as 0.

Code

<Rad:RadTreeView ID="tvwTreeDetails" runat="server" Width="400px"  AfterClientCheck="AfterCheckLookup" OnClientNodeChecked="AfterCheck" OnClientNodeClicked="AfterCheck" OnClientNodeClicking="AfterCheck"
                        OnClientNodeChecking="ClientNodeChecking" MultipleSelect="true" CheckBoxes="true" TriStateCheckBoxes="true" ></Rad:RadTreeView>

function AfterCheck(sender, args) {
    var node = args.get_node();

<telerik:RadCalendar  ID="cldDates" runat="server" AutoPostBack="true" OnDayRender="rCalander_Render"  ShowRowHeaders="false" ShowOtherMonthsDays="false" MultiViewRows="3" Skin="Simple">
</telerik:RadCalendar>

        List<DateTime> enddates = new List<DateTime>();
        List<DateTime> StartDates = new List<DateTime>();
        public void rCalander_Render(object sender, Telerik.Web.UI.Calendar.DayRenderEventArgs e)
        {
 
            var bookingdates2 = from d in DbContext.ihh_Bookings where d.lngHouseID == HouseID && d.dtmEndDate >= new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1) && (d.lngBookingStatusID != 7 && d.lngBookingStatusID != 1 && d.lngBookingStatusID != 10) select d;
 
 
            foreach (ihh_Booking w in bookingdates2)
            {
 
 
                //var bookingdates = from d in DbContext.ihh_HouseBookings_Webs where d.HouseID == HouseID select d;
                //foreach (ihh_HouseBookings_Web w in bookingdates)
                //{
 
                if (e.Day.Date == w.dtmStartDate)
                {
 
                    StartDates.Add(w.dtmStartDate.Value);
                }
                if (e.Day.Date >= w.dtmStartDate && e.Day.Date <= w.dtmEndDate)
                {
                    e.Day.IsSelectable = false;
                    e.Cell.BackColor = System.Drawing.Color.Red;
                    e.Cell.ToolTip = "Booked";
                    cldDates.SpecialDays.Add(e.Day);
 
                }
 
                if (e.Day.Date == w.dtmEndDate)
                {
                    e.Day.IsSelectable = false;
                    e.Cell.BackColor = System.Drawing.Color.FromArgb(Convert.ToInt32("1EA7D8", 16));
                    e.Cell.ToolTip = "Check Out";
                    cldDates.SpecialDays.Add(e.Day);
                    enddates.Add(w.dtmEndDate.Value);
                }
 
 
            }
            foreach (DateTime t in StartDates)
            {
 
                if (enddates.Contains(t) && e.Day.Date == t)
                {
                    e.Day.IsSelectable = false;
                    e.Cell.BackColor = System.Drawing.Color.Purple;
                    e.Cell.ToolTip = "Check out/In";
                    cldDates.SpecialDays.Add(e.Day);
                }
 
            }
            DateTime dtStartDate = (cldDates.CalendarView as Telerik.Web.UI.Calendar.View.MonthView).MonthStartDate;
            DateTime dtEndDate = (cldDates.CalendarView as Telerik.Web.UI.Calendar.View.MonthView).MonthEndDate;
 
            if ((e.Day.Date < dtStartDate || e.Day.Date > dtEndDate))
            {
                // e.Cell.Visible = false;
                e.Cell.BackColor = System.Drawing.Color.White;
 
            }

        }