public class DaysExceptionRule :
    ExceptionRule,
    INotifyCollectionChanged<ExceptionDay>

Public Class DaysExceptionRule
    Inherits ExceptionRule
    Implements INotifyCollectionChanged(Of ExceptionDay)

using DevExpress.XtraGantt.Exceptions;

DaysExceptionRule rule = new DaysExceptionRule() {
    StartDate = new DateTime(2019, 9, 12),
    Interval = 2
};
WorkTime morningWorkTime = new WorkTime(9, 12);
WorkTime afternoonWorkTime = new WorkTime(13, 18);
rule.Days.Add(new ExceptionDay(morningWorkTime));
rule.Days.Add(new ExceptionDay(afternoonWorkTime));

Imports DevExpress.XtraGantt.Exceptions

Dim rule As New DaysExceptionRule() With {
    .StartDate = New Date(2019, 9, 12),
    .Interval = 2
}
Dim morningWorkTime As New WorkTime(9, 12)
Dim afternoonWorkTime As New WorkTime(13, 18)
rule.Days.Add(New ExceptionDay(morningWorkTime))
rule.Days.Add(New ExceptionDay(afternoonWorkTime))

using DevExpress.XtraGantt;
using DevExpress.XtraGantt.Base.Scheduling;
using DevExpress.XtraGantt.Exceptions;
using DevExpress.XtraGantt.Scheduling;

private ExceptionRule[] CreateCustomRules() {

    DailyExceptionRule dailyException = new DailyExceptionRule() {
        StartDate = new DateTime(2019, 8, 19),
        Occurrences = 7
    };
    dailyException.WorkTimes.Add(new WorkTime(9, 12));

    DaysExceptionRule daysException = new DaysExceptionRule() {
        StartDate = new System.DateTime(2023, 9, 27, 0, 0, 0, 0),
        Occurrences = 1
    };

    // The rule applies to the first day of each month (January, 1; February, 1; etc.)
    MonthlyExceptionRule FirstDayInMonth = new MonthlyExceptionRule() {
        DayOfMonth = 1
    };
    FirstDayInMonth.Add(new WorkTime(10, 12));

    // The rule applies to the second Friday of each month.
    MonthlyDayOfWeekExceptionRule SecondFridayInMonth = new MonthlyDayOfWeekExceptionRule() {
        DayOfWeek = DayOfWeek.Friday,
        WeekOfMonth = WeekOfMonth.Second
    };
    SecondFridayInMonth.Add(new WorkTime(9, 12));

    // The rule applies to 31st December 5 times 
    // each two years starting from 12/31/2019.
    YearlyExceptionRule December31 = new YearlyExceptionRule() {
        DayOfMonth = 31,
        Month = Month.December,
        StartDate = new DateTime(2019, 12, 31),
        Interval = 2,
        Occurrences = 5
    };
    December31.Add(new WorkTime(9, 11));

    //The rule applies to the 256th day each year.
    YearlyDayOfYearExceptionRule Day256 = new YearlyDayOfYearExceptionRule() {
        DayOfYear = 256,
    };
    // Specify work hours for the 256th day.
    Day256.WorkTimes.Add(new WorkTime(9, 12));

    return new ExceptionRule[] { SecondFridayInMonth, FirstDayInMonth, dailyException, daysException, Day256, December31 };
}
ganttControl1.Exceptions.AddRange(CreateCustomRules());

Imports DevExpress.XtraGantt
Imports DevExpress.XtraGantt.Base.Scheduling
Imports DevExpress.XtraGantt.Exceptions
Imports DevExpress.XtraGantt.Scheduling

Private Function CreateCustomRules() As ExceptionRule()

    Dim dailyException As New DailyExceptionRule() With {
        .StartDate = New Date(2019, 8, 19),
        .Occurrences = 7
    }
    dailyException.WorkTimes.Add(New WorkTime(9, 12))

    Dim daysException As New DaysExceptionRule() With {
        .StartDate = New Date(2023, 9, 27, 0, 0, 0, 0),
        .Occurrences = 1
    }

    ' The rule applies to the first day of each month (January, 1; February, 1; etc.)
    Dim FirstDayInMonth As New MonthlyExceptionRule() With {.DayOfMonth = 1}
    FirstDayInMonth.Add(New WorkTime(10, 12))

    ' The rule applies to the second Friday of each month.
    Dim SecondFridayInMonth As New MonthlyDayOfWeekExceptionRule() With {
        .DayOfWeek = DayOfWeek.Friday,
        .WeekOfMonth = WeekOfMonth.Second
    }
    SecondFridayInMonth.Add(New WorkTime(9, 12))

    ' The rule applies to 31st December 5 times 
    ' each two years starting from 12/31/2019.
    Dim December31 As New YearlyExceptionRule() With {
        .DayOfMonth = 31,
        .Month = Month.December,
        .StartDate = New Date(2019, 12, 31),
        .Interval = 2,
        .Occurrences = 5
    }
    December31.Add(New WorkTime(9, 11))

    'The rule applies to the 256th day each year.
    Dim Day256 As New YearlyDayOfYearExceptionRule() With {.DayOfYear = 256}
    ' Specify work hours for the 256th day.
    Day256.WorkTimes.Add(New WorkTime(9, 12))

    Return New ExceptionRule() { SecondFridayInMonth, FirstDayInMonth, dailyException, daysException, Day256, December31 }
End Function
ganttControl1.Exceptions.AddRange(CreateCustomRules())