collections.md

Collections in the Microsoft Graph SDK for iOS

Getting a collection

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

[[[[[[graphClient me] drive] items:<item_id>] children] request] getWithCompletion:
    ^(MSCollection *children, MSGraphDriveItemChildrenCollectionRequest *nextRequest, NSError *error){
        // Returns a MSCollection, 
        // another children request if there are more children to get, 
        // or an error if one occurred.
}];

MSCollection has the following:

Name	Description
value	An NSArray of entity types, e.g. MSGraphDriveItem
nextLink	An NSURL used to get to the next page of items, if another page exists.
additionData	An NSDictionary to any additional values returned by the service. In this case, none.

The completion handler also supplies a request object called nextRequest of the same type as the original request. If there is another page of items this object can be used to make the next page request on the collection. If there are no pages left this object will be nil.

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 addItem method:

MSGraphDriveItem *newFolder = [[MSGraphDriveItem alloc] init];
newFolder.name = <new_folder_name>;
newFolder.folder = [[MSGraphFolder alloc] init];
[[[[[[graphClient me] drive] items:<item_id>] children] request] addItem:newFolder withCompletion:^(MSGraphDriveItem *item, NSError *error){
    //returns the new item or an error if there was one.
}];

Expanding a collection

To expand a collection, you call expand on the CollectionRequest object with the string you want to expand:

MSGraphDriveItemChildrenCollectionRequest *request = [[[[[[[odClient] me] drive] items:<item_id>] children] request] expand:@"<property to expand>"];

[request getWithCompletion:^(MSCollection *children, MSGraphDriveItemChildrenCollectionRequest *nextRequest, NSError *error){
    // children will have a collection of MSGraphDriveItems, that will have the relevant property populated
}];

Collections as entity properties

Collections that are returned as part of an entity, as opposed to requesting the collection directly, are exposed as an NSArray of contained types. For example, if a MSGraphDriveItem is requested with children expanded:

[[[[[[graphClient me] drive] root] request] expand:@"children"] getWithCompletion:^(MSGraphDriveItem *item, NSError *error) {
    // item.children is an NSArray of MSGraphDriveItem
    for (MSGraphDriveItem *child in item.children) {
        // Do something with the child item
    }
}];