collections.md

Collections in the Microsoft Graph .NET Client Library

Whenever a request returns a collection of objects that allow paging or navigation into the collection, the library generates a complex collection page object.

Getting a collection

To retrieve a collection, like the list of groups in the service, you call GetAsync on the collection request:

await graphServiceClient
	    .Groups
	    .Request()
	    .GetAsync();

GetAsync returns an ICollectionPage<T> implementation on success and throws a ServiceException on error. For the groups collection, the type returned is IGraphServiceGroupsCollectionPage, which inherits ICollectionPage<Item>.

IGraphServiceGroupsCollectionPage contains three properties:

Name	Description
CurrentPage	An IList<Item>.
NextPageRequest	An IGraphServiceGroupsCollectionRequest 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.
AdditionalData	An IDictionary<string, object> to any additional values returned by the service. In this case, none.

Adding to a collection

Some collections, like the groups collection, can be changed. To create a group you can call:

var groupToCreate = new Group
    {
		GroupTypes = new List<string> { "Unified" },
		DisplayName = "Unified group",
		Description = "Best group ever",
		...
	};
	
var newGroup = await graphServiceClient
                         .Groups
						 .Request()
						 .AddAsync(groupToCreate);

AddAsync returns the created group on success and throws a ServiceException 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 graphServiceClient
                         .Me
                         .Drive
						 .Items[itemId]
						 .Children
						 .Request()
						 .Expand("thumbnails")
						 .GetAsync();