StorageItem object (Outlook)

A message object in MAPI that is always saved as a hidden item in the parent folder and stores private data for Outlook solutions.


A StorageItem object is stored at the folder level, allowing it to roam with the account and be available online or offline.

The Outlook object model does not provide any collection object for StorageItem objects. However, you can use Folder.GetTable to obtain a Table with all the hidden items in a Folder, when you specify the TableContents parameter as olHiddenItems. If keeping your data private is of a high concern, you should encrypt the data before storing it.

Once you have obtained a StorageItem object, you can do the following to store solution data:

  • Add attachments to the item for storage.

  • Use explicit built-in properties of the item such as Body to store custom data.

  • Add custom properties to the item using UserProperties.Add method. Note that in this case, the optional AddToFolderFields and DisplayFormat arguments of the UserProperties.Add method will be ignored.

  • Use the PropertyAccessor object to get or set custom properties.

The default message class for a new StorageItem is IPM.Storage. If the StorageItem existed as a hidden message in a version of Outlook prior to Microsoft Office Outlook 2007, the message class will remain unchanged. In order to prevent modification of the message class, StorageItem does not expose an explicit MessageClass property.

For more information on storing solution data using the StorageItem object, see Storing Data for Solutions.


The following code sample in Visual Basic for Applications shows how to use the StorageItem object to store private solution data. It saves the data in a custom property of a StorageItem object in the Inbox folder. The following describes the steps.

  1. The code sample calls Folder.GetStorage to obtain an existing StorageItem object that has the subject "My Private Storage" in the Inbox. If no StorageItem with that subject already exists, GetStorage creates a StorageItem object with that subject.

  2. If the StorageItem is newly created, the code sample creates a custom property "Order Number" for the object. Note that "Order Number" is a property of a hidden item in the Inbox.

  3. The code sample then assigns a value to "Order Number" and saves the StorageItem object.

Sub AssignStorageData() 
 Dim oInbox As Outlook.Folder 
 Dim myStorage As Outlook.StorageItem 
 Set oInbox = Application.Session.GetDefaultFolder(olFolderInbox) 
 ' Get an existing instance of StorageItem, or create new if it doesn't exist 
 Set myStorage = oInbox.GetStorage("My Private Storage", olIdentifyBySubject) 
 ' If StorageItem is new, add a custom property for Order Number 
 If myStorage.Size = 0 Then 
 myStorage.UserProperties.Add "Order Number", olNumber 
 End If 
 ' Assign a value to the custom property 
 myStorage.UserProperties("Order Number").Value = 100 
End Sub 





See also

Outlook Object Model Reference

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