OL97: Programming With EntryIDs, StoreIDs, and GetItemFromID (170991)

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Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft Support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs. If you have limited programming experience, you may want to contact the Microsoft fee-based consulting line at (800) 936-5200. For more information about the support options available from Microsoft, please see the following page on the World Wide Web: A common use of the GetItemFromID method is to create a link, or relationship, from one Outlook item to another. The Outlook Visual Basic Help file (Vbaoutl.hlp) documents this method.

For more information on obtaining the Outlook Visual Basic Help file, please see the following article in the Microsoft Knowledge Base: An example of when you might want to use the GetItemFromID method is if you created contact items for all members of a family instead of just having one contact item for the head of the household. You might want to create a custom contact form so that you can create "links" between all members of the family. This could be in the form of a list box on the custom contact form that would automatically include a list of other members of the family. Using the custom form, when you select a person from the list, their contact item would automatically display.

In a solution like this, you would typically create the links between the contact items by storing the related IDs with each contact. So each contact item might have 20 user-defined fields that store the IDs of up to 20 related contacts. VBScript code uses these IDs to retrieve the names of the other family members in order to populate the list and to retrieve the other contact item when the user selects a name from the list.

Each Outlook item (contacts, messages, appointments, and such) has a field called EntryID, which is a unique ID field generated by the messaging storage system for use with the MAPI folders which store the item.

Each MAPI folder has a field called StoreID, a unique ID field for that particular folder. Each folder also has an EntryID field.

When using the GetItemFromID method to retrieve an item based on its MAPI IDs, you need to specify both the EntryID of the item and the StoreID of the folder. Using the EntryID of the folder instead of the StoreID will generate an error, which may vary depending on the type of folder you are working with.

The following is a VBScript example which illustrates the use of the GetItemFromID method. The code retrieves the StoreID from the default Contacts folder, fills an array with the EntryIDs for all of the contacts in the folder, and finally retrieves a specific contact item.

   Sub OutlookEntryID()
   'The Outlook object library must be referenced
   Dim ol As Outlook.Application
   Dim olns As NameSpace
   Dim objFolder As Object
   Dim AllContacts As Object
   Dim Item As Object
   Dim I As Integer
   'If there are more than 500 contacts, change the following line:
   Dim EntryID(500) As String
   Dim StoreID As String
   Dim strFind As String
   ' Set the application object
   Set ol = New Outlook.Application
   ' Set the namespace object
   Set olns = ol.GetNamespace("MAPI")
   ' Set the default Contacts folder
   Set objFolder = olns.GetDefaultFolder(olFolderContacts)
   ' Get the StoreID, which is a property of the folder
   StoreID = objFolder.StoreID
   ' Set objAllContacts = the collection of all contacts
   Set AllContacts = objFolder.Items
   I = 0
   ' Loop to get all of the EntryIDs for the contacts
   For Each Item In AllContacts
      I = I + 1
      ' The EntryID is a property of the item
      EntryID(I) = Item.EntryID
   Next
   ' Randomly choose the 2nd Contact to retrieve
   ' In a larger solution, this might be the index from a listbox
   I = 2
   ' Both the StoreID and EntryID must be used to retrieve the item
   Set Item = olns.GetItemFromID(EntryID(I), StoreID)
   Item.Display
   End Sub