Collections in the OneDrive SDK for C#

You can use the OneDrive SDK for C# to work with item collections in OneDrive.

Getting a collection

To retrieve a collection, like a folder's children, you call GetAsync:

await oneDriveClient
          .Drive
		  .Items[itemId]
		  .Children
		  .Request()
		  .GetAsync();

GetAsync returns an ICollectionPage<T> implementation on success and throws a OneDriveException on error. For children collections, the type returned is IChildrenCollectionPage, which inherits ICollectionPage<Item>.

IChildrenCollectionPage contains three properties:

Name	Description
CurrentPage	An IList<Item>.
NextPageRequest	An IChildrenPageRequest used to get to the next page of items, if another page exists. This value will be null if there is not a next page.
AdditionData	An IDictionary<string, object> to any additional values returned by the service. In this case, none.

Adding to a collection

Some collections, like the children of a folder, can be changed. To add a folder to the children of an item, you can call the AddAsync method:

var folderToCreate = new Item { Name = "New folder", Folder = new Folder() };
var newFolder = await oneDriveClient
                          .Drive
						  .Items[itemId]
						  .Children
						  .Request()
						  .AddAsync(folderToCreate);

AddAsync returns the created item on success and throws a OneDriveException on error.

Expanding a collection

To expand a collection, you call Expand on the collection request object with the string value of the expand:

var children = await oneDriveClient
                         .Drive
						 .Items[itemId]
						 .Children
						 .Request()
						 .Expand("thumbnails")
						 .GetAsync();

Special collections

Some API calls will return collections with added properties. These properties will always be in the additional data dictionary. These collections are also their own objects (subclasses of ICollectionPage<T>) that will have these properties attached to them.

To get the delta of an item you call:

var deltaCollectionPage = await oneDriveClient
                                    .Drive
									.Items[itemId]
									.Delta(deltaToken)
									.Request()
									.GetAsync();

IItemDeltaCollectionPage is an ICollectionPage<Item> object with a Token property and a DeltaLink property. The token link can be used to pass into Delta: when you want to check for more changes. You can also construct a delta request with the DeltaLink property. The NextPageRequest is an IItemDeltaRequest to be used for paging purposes and will be null when there are no more changes.