The SetColumns method allows the user to cache certain properties for extremely fast access to those particular properties of the item. The SetColumns method is useful for iterating through the Items object. If you don't use this method, Microsoft Outlook must open each item to access the property. With the SetColumns method, Outlook only checks the properties that you have cached. Properties which are not cached are returned empty.
expression Required. An expression that returns one of the objects in the Applies To list.
Columns Required. A String containing the names of the properties to be cached, separated by commas.
For the Items object, SetColumns cannot be used, and will cause an error, with any property that returns an object, and it cannot be used with the following properties:
Note The ConversationIndex property cannot be cached using the SetColumns method in Office Outlook 2003. However, this property will not result in an error like the other properties listed above.
The following Visual Basic for Applications (VBA) example uses the Items collection to get the items in default Tasks folder, caches the Subject and DueDate properties and then displays the subject and due dates each in turn.
Sub SortByDueDate() Dim myOlApp As New Outlook.Application Dim myNameSpace As Outlook.NameSpace Dim myFolder As Outlook.MAPIFolder Dim myItem As Object Dim myItems As Outlook.Items Set myNameSpace = myOlApp.GetNamespace("MAPI") Set myFolder = myNameSpace.GetDefaultFolder(olFolderTasks) Set myItems = myFolder.Items myItems.SetColumns ("Subject, DueDate") For Each myItem In myItems MsgBox myItem.Subject & " " & myItem.DueDate Next myItem End Sub