public List<SchedulerRecurrenceType> RepeatItems { get; set; }

<DxScheduler DataStorage="@DataStorage" 
             AppointmentFormMode="SchedulerAppointmentFormMode.EditForm"
             AppointmentFormShowing="OnAppointmentFormShowing">
    <DxSchedulerWeekView ShowWorkTimeOnly="true" />
</DxScheduler>

@code {
    DxSchedulerDataStorage DataStorage = new DxSchedulerDataStorage() {
            AppointmentsSource = AppointmentCollection.GetAppointments(),
            AppointmentMappings = new DxSchedulerAppointmentMappings() {
                Start = "StartDate",
                End = "EndDate",
                Subject = "Caption",
                LabelId = "Label",
                StatusId = "Status"
            }
        };

    void OnAppointmentFormShowing(SchedulerAppointmentFormEventArgs args) {
        args.FormInfo.RepeatItems = new List<SchedulerRecurrenceType>() {
            SchedulerRecurrenceType.Yearly,
            SchedulerRecurrenceType.Weekly,
            SchedulerRecurrenceType.Never
        };
        ...
    }
}

public class Appointment {
    public Appointment() {}
    public int AppointmentType { get; set; }
    public DateTime StartDate { get; set; }
    public DateTime EndDate { get; set; }
    public string Caption { get; set; }
    public string Description { get; set; }
    public string Location { get; set; }
    public int Label { get; set; }
    public int Status { get; set; }
    public bool AllDay { get; set; }
    public string Recurrence { get; set; }
    public bool Accepted { get; set; }
}

public static partial class AppointmentCollection {
    public static List<Appointment> GetAppointments() {
        DateTime date = DateTime.Today;
        var dataSource = new List<Appointment>() {
                new Appointment {
                    Caption = "Install New Router in Dev Room",
                    StartDate = date + (new TimeSpan(0, 10, 0, 0)),
                    EndDate = date + (new TimeSpan(0, 12, 30, 0)),
                    Label = 6,
                    Status = 4
                },
                new Appointment {
                    Caption = "Upgrade Personal Computers",
                    StartDate = date + (new TimeSpan(0, 13, 0, 0)),
                    EndDate = date + (new TimeSpan(0, 15, 30, 0)),
                    Label = 1,
                    Status = 4
                },
                new Appointment {
                    Caption = "Website Redesign Plan",
                    StartDate = date + (new TimeSpan(1, 9, 30, 0)),
                    EndDate = date + (new TimeSpan(1, 12, 0, 0)),
                    Label = 1,
                    Status = 1,
                    Accepted = true
                },
                new Appointment {
                    Caption = "New Brochures",
                    StartDate = date + (new TimeSpan(1, 13, 30, 0)),
                    EndDate = date + (new TimeSpan(1, 15, 15, 0)),
                    Label = 8,
                    Status = 2,
                    Accepted = true
                },
                // ...
            };
        return dataSource;
    }
}