or
public class CalendarItemViewModel : AppointmentBase{ public LaborTrackingSession Model { get; private set; } public override DateTime Start { get { return Model.StartTime.DateTime; } set { Model.StartTime = value; OnPropertyChanged(() => Start); } } public override DateTime End { get { return Model.EndTime.HasValue ? Model.EndTime.Value.DateTime : SystemTime.Now().DateTime; } set { Model.EndTime = value; OnPropertyChanged(() => End); } } ...}<telerik:GridViewDataColumn Header="Start Date" Width="135" Name="StartDateColumn" EditTriggers="CurrentCellClick" DataFormatString="{}{0:M/d/yyyy hh:mm tt}" CellStyleSelector="{StaticResource startDateCellStyleSelector}" DataMemberBinding="{Binding StartDate}"> <telerik:GridViewDataColumn.CellEditTemplate> <DataTemplate> <telerik:RadDateTimePicker SelectableDateStart="{Binding SelectableStartDate}" SelectedValue="{Binding StartDate, Mode=TwoWay}"/> </DataTemplate> </telerik:GridViewDataColumn.CellEditTemplate> <telerik:GridViewDataColumn.HeaderCellStyle> <Style TargetType="telerik:GridViewHeaderCell"> <Setter Property="Background" Value="#437F7B"/> <Setter Property="Foreground" Value="White"/> </Style> </telerik:GridViewDataColumn.HeaderCellStyle></telerik:GridViewDataColumn>