GetFreeBusy Method (Recipients Collection)

GetFreeBusy Method (Recipients Collection)

Exchange Server 2003

Topic Last Modified: 2004-06-09

The GetFreeBusy method returns a string representing the combined availability of all recipients for a meeting over a specified period of time.

strAvail = objRecipColl.GetFreeBusy(StartTime, EndTime, Interval)


On successful return, contains a string indicating the recipients' availability for each of the time slots in the specified time period.


Required. The Recipients collection object.


Required. Variant (vbDate format). Specifies the date/time of the beginning of the first time slot.


Required. Variant (vbDate format). Specifies the date/time of the end of the last time slot.


Required. Long. Specifies the length of each time slot in minutes. If this parameter is less than 1, GetFreeBusy returns CdoE_INVALID_PARAMETER.

The returned string length equals the number of time slots between StartTime and EndTime. Each character is the ASCII representation of the appropriate type library constant indicating the recipients' combined availability during a time slot:

ASCII character

Corresponding type library constant




Available for appointments or meetings throughout the time slot



At least one tentative commitment during the time slot



At least one confirmed commitment during the time slot



Designated as out-of-office (OOF) for at least part of the time slot

If there is any overlapping of commitments during a time slot, GetFreeBusy returns the most committed state, that is, the highest character value. For example, if one recipient already has a tentative meeting and another has a confirmed meeting scheduled during the same time slot, GetFreeBusy returns "2" for that time slot, corresponding to CdoBusy. CdoFree is not returned unless the entire time slot is free of commitments.

For performance reasons, calendaring clients typically do not publish appointments indefinitely into the future. For example, the CDO Library, Microsoft® Outlook®, Microsoft® Schedule+, and Microsoft Outlook Web Access (OWA) all publish appointments for a default maximum of three months including the current date. You can change this maximum by supplying "FreeBusyMonths" in the OptType parameter of the Session object's SetOption method.

The free/busy information is always published from the beginning of the current month. A consequence of this is that when the date is near the end of the current month, GetFreeBusy effectively returns future appointment information for one month less than the "FreeBusyMonths" option indicates.

If you call GetFreeBusy on a messaging user and specify time slots occupying more months than "FreeBusyMonths" allows, GetFreeBusy is likely to return CdoFree for every time slot past the maximum. Unless you are familiar with the behavior and publishing limits of a messaging user's calendaring client, you should not interpret CdoFree as meaning that the user is genuinely free for a time slot significantly in the future.

When a messaging user creates an appointment using Outlook, the calendar is not updated until logoff from Outlook. This means that changes to that user's free/busy information are not available to other messaging users until the Outlook user logs off.

When a messaging user's mailbox is first created using either Outlook or a CDO application, its free/busy information is not initialized until the user calls a method, such as GetDefaultFolder or GetFreeBusy, that initializes this information. If another messaging user calls GetFreeBusy on that user before the free/busy information is initialized, CDO returns CdoE_NOT_FOUND. This is not the case with a Schedule+ mailbox, which initializes its free/busy information immediately upon creation.

If a recipient represents a distribution list, the status of its individual members cannot be returned to you. A meeting request should be sent only to single messaging users. You can determine if a messaging user is a distribution list by checking the DisplayType property of the AddressEntry object representing that user. You can obtain the AddressEntry object underlying a recipient from that Recipient object's AddressEntry property.

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