Google People API C# code to get list of contact groups

Question

I'm using the new Google People API to load the list of a user's Google contacts into my app. Here's some of my class - as I said it's straight from the online guide and it works fine. However I can't find any similar code to load the list of contact groups (eg family, workmates etc). I got this working before with the Contacts API and there is lots of sample code for that, but I can't find any for the People API. If this is still too broad a question please suggest how I can be more specific. Thanks.

using Google.Apis.Auth.OAuth2;
using Google.Apis.People.v1.Data;
using Google.Apis.People.v1;
using Google.Apis.Services; 

public class GoogleContacts
{
    private String m_client_secret = ".....";
    private String m_client_id = "......apps.googleusercontent.com";

    public GoogleContacts()
    {
        // Create OAuth credential.
        UserCredential credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
            new ClientSecrets
            {
                ClientId = m_client_id,
                ClientSecret = m_client_secret
            },
            new[] { "profile", "https://www.googleapis.com/auth/contacts.readonly" },
            "me",
            CancellationToken.None).Result;

        // Create the service.
        var service = new PeopleService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = "MyApp",
        });
        PeopleResource.ConnectionsResource.ListRequest peopleRequest =
            service.People.Connections.List("people/me");
        peopleRequest.RequestMaskIncludeField = new List<string>() {
        "person.addresses",
        "person.names"  };
        peopleRequest.SortOrder = (PeopleResource.ConnectionsResource.ListRequest.SortOrderEnum) 1;

       ListConnectionsResponse people = peopleRequest.Execute();

        if (people != null && people.Connections != null && people.Connections.Count > 0)
        {

            foreach (var person in people.Connections)
            {  //do stuff with people

// etc...

Answer 1

I eventually found a way to do it. Notice it's using PeopleService.v1 rather than People.v1. Here's a class to show the list of groups then the list of contacts:

using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;
using Google.Apis.PeopleService.v1;
using Google.Apis.PeopleService.v1.Data;

public class GoogleContacts
{

    private String m_client_secret = "......";
    private String m_client_id = ".......apps.googleusercontent.com";

    public GoogleContacts()
    {
        // Create OAuth credential.
        UserCredential credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
            new ClientSecrets
            {
                ClientId = m_client_id,
                ClientSecret = m_client_secret
            },
            new[] { "profile", "https://www.googleapis.com/auth/contacts.readonly" },
            "me",
            CancellationToken.None).Result;

        // Create the service.
        var service = new PeopleServiceService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = "My App",
        });

        // Groups list ////////////
        ContactGroupsResource groupsResource = new ContactGroupsResource(service);
        ContactGroupsResource.ListRequest listRequest = groupsResource.List();
        ListContactGroupsResponse response = listRequest.Execute();

        // eg to show name of each group
        List<string> groupNames = new List<string>();
        foreach (ContactGroup group in response.ContactGroups)
        {
            groupNames.Add(group.FormattedName);
        }
        ///////////////

        // Contact list ////////////
        PeopleResource.ConnectionsResource.ListRequest peopleRequest =
            service.People.Connections.List("people/me");
        peopleRequest.PersonFields = "names,emailAddresses";
        peopleRequest.SortOrder = (PeopleResource.ConnectionsResource.ListRequest.SortOrderEnum) 1;
        ListConnectionsResponse people = peopleRequest.Execute();

        // eg to show display name of each contact
        List<string> contacts = new List<string>();
        foreach (var person in people.Connections)
        {
            contacts.Add(person.Names[0].DisplayName);

        }
        ///////////////
    }
}