How to: Filter Items that Do Not Have Categories
|Outlook Developer Reference|
This topic shows a code sample that uses a DAV Searching and Locating (DASL) query to filter items in the current folder that do not have any category assigned to them. Note that filtering items with an empty string in their categories requires a DASL query; the Microsoft Jet syntax does not support such filters.
When filtering an empty string with a DASL query, you can use the Is Null keyword. Is Null operations are useful to determine if a string property is empty or if a date property has been set. For more information, see Filtering Items Using Query Keywords.
The code sample sets up a DASL filter on the Categories property, which in the DASL query is expressed in the Office namespace as urn:schemas-microsoft-com:office:office#Keywords. The filter compares the value of the Categories property with an emptry string using the Is Null keyword. The code sample then applies the filer to items in the current folder. It then prints the number of items in the current folder that have been found to have no categories.