Search Size and Page Size

The DirectorySearcher.SizeLimit and DirectorySearcher.PageSize properties both affect the number of items that are returned by a search. The SizeLimit property sets the maximum number of items that will be returned by a search, but there may be other search result limitations imposed by the underlying directory service. For example, Active Directory limits the maximum number of search results to 1000. In this case, setting the SizeLimit property to a value greater than 1000 has no effect.

The PageSize property sets the maximum number of items in each page of results that will be returned by a search. The page size is also affected by the underlying directory service. With Active Directory, the largest page size is 1000. Any value over 1000 will be ignored. If PageSize is set to its default value (zero), no paging will occur and the maximum number of items returned by the search will be the lesser of SizeLimit and 1000.

To retrieve a set of results that is larger than 1000 items, you must set SizeLimit to its default value (zero) and set PageSize to a value that is less than or equal to 1000. For example, if a search will result in 12,000 items being returned and SizeLimit is set to 500, a total of 500 items will be returned. If, however, SizeLimit is set to zero and PageSize is set to 500, the search will return all 12,000 results in pages of 500 items, with the last page containing only 200 items. The paging occurs transparently to the application and the application does not have to perform any special processing other than setting the PageSize property to the proper value.