Specifying Exceptions to Recurring Appointments and Meetings

Topic Last Modified: 2006-06-12

Exceptions are specific appointments that are added, modified, or deleted from the pattern of a recurring appointment or meeting. For example, if a recurring pattern generates a meeting that falls on a holiday, you can define an exception to that one instance of the recurring pattern.

Collaboration Data Objects (CDO) uses IRecurrencePattern objects and IException objects to define exceptions to recurring appointments and meetings. The following table shows how each object can be used.

Object	Type	Action
IRecurrencePattern	Add	Adds a set of instances.
IRecurrencePattern	Delete	Deletes a set of instances.
IException	Add	Adds a single instance.
IException	Delete	Deletes a single instance.
IException	Modify	Changes the properties of one or more instances (equivalent to a Microsoft® Outlook® exception).

To specify an exception to a recurring appointment or a meeting

1. Create the recurring appointment or meeting.
2. Create an Exception object by using the Add method on the Exceptions collection of the Appointment object, or create a RecurrencePattern object by using the Add method on the RecurrencePatterns collection.
3. Set the properties of the Exception or RecurrencePattern object to specify appointment instances that are being added, deleted, or modified.

This topic contains Microsoft Visual Basic®, Microsoft C#, and Visual Basic .NET code examples.

Example

Visual Basic

The following example creates a recurring meeting and reschedules the 7th instance to start 2 hours later.

' Reference to Microsoft ActiveX Data Objects 2.5 Library
' Reference to Microsoft CDO for Exchange 2000 Library

' Note: It is recommended that all input parameters be validated when they are
' first obtained from the user or user interface.
Function CreateApptWithException(iMbx As IMailbox) As CDO.Appointment

    Dim iAppt       As New Appointment
    Dim Config      As New Configuration
    Dim RRULE       As IRecurrencePattern
    Dim iCalMsg     As CalendarMessage
    Dim EXDATE      As IException
    Dim RDATE       As IException
    Dim Conn        As New ADODB.Connection
    Conn.Provider = "ExOLEDB.DataSource"

    With iAppt
        'Set the first appointment properties
        .StartTime = Now
        .EndTime = DateAdd("n", 60, Now)   ' 60 minute appointment starting now
        .Subject = "Read the Exchange SDK Docs."
        .Location = "My Office"

        'Create the RecurrencePattern object
        Set RRULE = .RecurrencePatterns.Add("Add")

        'Define the recurrence pattern
        RRULE.Frequency = cdoDaily  'use a daily pattern
        RRULE.Interval = 1  'every day
        RRULE.PatternEndDate = DateAdd("d", 7, Now) 'the last appointment, 7 days from now at this time.

        'Delete an appointment instance
        Set EXDATE = .Exceptions.Add("Delete")
        'The ID is the start time of the instance being deleted
        EXDATE.RecurrenceID = DateAdd("d", 7, Now) ' Except the 7th day...reschedule.

        'Add an appointment instance
        Set RDATE = .Exceptions.Add("Add")
        ' Start 2 hours later on the seventh day
        RDATE.StartTime = DateAdd("n", -60, DateAdd("d", 7, Now))
        RDATE.EndTime = DateAdd("d", 7, Now)

        'Save the appointment to the organizer's calendar
        Conn.Open iMbx.BaseFolder
        .DataSource.SaveToContainer iMbx.Calendar, Conn

    ' Clean up.
        Conn.Close
        Set Conn = Nothing

    End With
    Set CreateApptWithException = iAppt

End Function

C#

The following example creates a recurring meeting and reschedules the 7th instance to start 2 hours later.

// Reference to Microsoft ActiveX Data Objects 2.5 Library
// Reference to Microsoft CDO for Exchange 2000 Library

// Note: It is recommended that all input parameters be validated when they are
// first obtained from the user or user interface.
static CDO.Appointment CreateApptWithException(CDO.IMailbox iMbx)
{
   try
   {
      // Variables.
      CDO.Appointment iAppt = new CDO.Appointment();
      CDO.Configuration Config = new CDO.Configuration();
      CDO.IRecurrencePattern RRULE;
      CDO.IException EXDATE;
      CDO.IException RDATE;
      ADODB.Connection Conn = new ADODB.Connection();
      Conn.Provider = "ExOLEDB.DataSource";

      // Set the first appointment properties.
      iAppt.StartTime = DateTime.Now;

      // Set the end time for 60 minutes from now.
      iAppt.EndTime = DateTime.Now.Add(TimeSpan.FromMinutes(60));
      iAppt.Subject = "Read the Exchange SDK Docs.";
      iAppt.Location = "My Office";

      // Create the RecurrencePattern object.
      RRULE = iAppt.RecurrencePatterns.Add("Add");

      // Define the recurrence pattern.  Use the daily pattern.
      RRULE.Frequency = CDO.CdoFrequency.cdoDaily;

      // Every day.
      RRULE.Interval = 1;

      // The last appointment, 7 days from now at this time.
      RRULE.PatternEndDate = DateTime.Now.Add(TimeSpan.FromDays(7));

      // Delete an appointment instance.
      EXDATE = iAppt.Exceptions.Add("Delete");

      // Reschedule the 7th day.  The ID is the start time of
      // the instance being deleted.
      EXDATE.RecurrenceID = DateTime.Now.Add(TimeSpan.FromDays(7));

      // Add an appointment instance.
      RDATE = iAppt.Exceptions.Add("Add");

      // Start 2 hours later on the seventh day.
      RDATE.StartTime = DateTime.Now.Add(TimeSpan.FromDays(7)-TimeSpan.FromMinutes(60));
      RDATE.EndTime = DateTime.Now.Add(TimeSpan.FromDays(7));

      // Save the appointment to the organizer's calendar.
      Conn.Open(iMbx.BaseFolder, "", "", -1);

      iAppt.DataSource.SaveToContainer(iMbx.Calendar, Conn,
         ADODB.ConnectModeEnum.adModeReadWrite,
         ADODB.RecordCreateOptionsEnum.adCreateNonCollection,
         ADODB.RecordOpenOptionsEnum.adOpenSource, "", "");

      Console.WriteLine("Appointment created.");

      // Close the connection.
      Conn.Close();

      return iAppt;
   }

   catch (Exception err)
   {
      Console.WriteLine(err.ToString());
      return null;
   }
}

Visual Basic .NET

The following example creates a recurring meeting and reschedules the 7th instance to start 2 hours later.

' Reference to Microsoft ActiveX Data Objects 2.5 Library
' Reference to Microsoft CDO for Exchange 2000 Library

' Note: It is recommended that all input parameters be validated when they are
' first obtained from the user or user interface.
Function CreateApptWithException(ByVal iMbx As CDO.IMailbox) As CDO.Appointment

Try
   ' Variables.
   Dim iAppt As New CDO.Appointment()
   Dim Config As New CDO.Configuration()
   Dim RRULE As CDO.IRecurrencePattern
   Dim EXDATE As CDO.IException
   Dim RDATE As CDO.IException
   Dim Conn As New ADODB.Connection()
   Conn.Provider = "ExOLEDB.DataSource"

   With iAppt

      ' Set the first appointment properties.
      .StartTime = Now

      ' Set the end time for 60 minutes from now.
      .EndTime = DateAdd(DateInterval.Minute, 60, Now)
      .Subject = "Read the Exchange SDK Docs."
      .Location = "My Office"

      ' Create the RecurrencePattern object.
      RRULE = .RecurrencePatterns.Add("Add")

      ' Define the recurrence pattern.  Use the daily pattern.
      RRULE.Frequency = CDO.CdoFrequency.cdoDaily

      ' Every day.
      RRULE.Interval = 1

      ' The last appointment, 7 days from now at this time.
      RRULE.PatternEndDate = DateAdd(DateInterval.Day, 7, Now)

      ' Delete an appointment instance.
      EXDATE = .Exceptions.Add("Delete")

      ' Reschedule the 7th day.  The ID is the start time of
      ' the instance being deleted.
      EXDATE.RecurrenceID = DateAdd(DateInterval.Day, 7, Now)

      ' Add an appointment instance.
      RDATE = .Exceptions.Add("Add")

      ' Start 2 hours later on the seventh day.
      RDATE.StartTime = DateAdd(DateInterval.Minute, -60, DateAdd(DateInterval.Day, 7, Now))
      RDATE.EndTime = DateAdd(DateInterval.Day, 7, Now)

      ' Save the appointment to the organizer's calendar.
      Conn.Open(iMbx.BaseFolder)
      .DataSource.SaveToContainer(iMbx.Calendar, Conn)

   End With

   Console.WriteLine("Appointment created.")

   ' Close the connection.
   Conn.Close()

   CreateApptWithException = iAppt

   Catch err As Exception
      Console.WriteLine(err.ToString())
      CreateApptWithException = Nothing
   End Try

End Function