public EwsItemList DownloadItemIds(
	FolderId id,
	ItemView view,
	bool unreadOnly
)

Public Function DownloadItemIds ( 
	id As FolderId,
	view As ItemView,
	unreadOnly As Boolean
) As EwsItemList

Parameters

id

Type: FolderId
The ID of the folder. Null reference (Nothing in Visual Basic) not allowed.

view

Type: ItemView
The settings which specify how many items to download, offset, and ordering. If a null reference, all the matching items are downloaded.

unreadOnly

Type: SystemBoolean
If true, only unread items are considered for download; otherwise, all the items.

Return Value

To specify the folder by its name, first get its ID with FindFolderIdByShortName(FolderId, String) or FindFolderIdByFullName(String) method.

Usually, you'll immediately pass the returned list to a method like DownloadItems(IEnumerableEwsItem, EwsItemParts). However, once you downloaded the item IDs, you can also store UniqueId values elsewhere and later recreate EwsItem objects from that strings using EwsItem(String) constructor.

Items are returned in the default sorting order which usually means "newer first" in Exchange. This is different from IMAP and POP3, where "older first" is the default.

Note
In the returned collection of EwsItem objects, you can access their Id and UniqueId properties only. Accessing other properties will cause an exception (because only ID was loaded for each item).

Note
This method is not implemented in .NET Core. Use DownloadItemIdsAsync(FolderId, ItemView, Boolean) instead.

Reference