MS Graph API C# Add user to group

Question

I've been investigating how to add (and later remove) a user from an Azure AD group using the Microsoft Graph API (the dotnet/C# library available on nuget).

Nuget MS Graph API

Ignoring all else around getting a connected GraphServiceClient etc. I'm trying code very similar to the sample below, not getting any exception (suggesting things are fine) but when I get the group once again via the API, it's not got any members still!

Interestingly (as an aside), when I ask for memberOf property on the user object and tell it to expand it, it comes back null still.

var user = await client.Users[userPrincipalName]
             .Request()
               .Select("id,memberOf")
                 .Expand("memberOf")
                   .GetAsync();

var group = await client.Groups[groupId]
              .Request()
                .Select("members")
                  .Expand("members")
                    .GetAsync();

group.Members.Add(user);

await client.Groups[groupId].Request().UpdateAsync(group);

// userPrincipalName => "test.user@mytenant.com"
// groupId => the object GUID for the group

Does anyone know what I'm doing wrong here? The docs I used to come up with this code were based on the links to the following documents:

API doc for 'group'

Adding a member to a group

Also, I tried to style the approach on the solution suggested here to setting licenses for users:

Assign user license via Graph API

As usual, thanks for any help.

Peter

Additional

I've also tried poking around in the graph API looking at potentially updating the .Members property/resource rather than the group itself:

await client.Groups[groupId].Members.Request(). // <-- Only has GetAsync()

But it only has the GetAync() method available to it.

Updated based on answer

var usersGroups = await client.Users[userPrincipalName].MemberOf.Request().GetAsync();

if (!usersGroups.Any(g => g is Group && g.Id == groupId))
{
    // User is not a member of the group, add them.
    var user = await client.Users[userPrincipalName].Request().Select("id").GetAsync();
    await client.Groups[groupId].Members.References.Request().AddAsync(user);
}

I've added the code snippet above based on the answer, as I think it succinctly answers the issue regarding adding members.

Thanks to Nan Yu for the answer.

Answer 1

To add user to Group ,you could use :

User userToAdd = await graphClient.Users["objectID"].Request().GetAsync(); 
await graphClient.Groups["groupObjectID"].Members.References.Request().AddAsync(userToAdd);

To get members of a group :

        List<ResultsItem> items = new List<ResultsItem>();

        // Get group members. 
        IGroupMembersCollectionWithReferencesPage members = await graphClient.Groups[id].Members.Request().GetAsync();

        if (members?.Count > 0)
        {
            foreach (User user in members)
            {
                // Get member properties.
                items.Add(new ResultsItem
                {
                    Properties = new Dictionary<string, object>
                    {
                        { Resource.Prop_Upn, user.UserPrincipalName },
                        { Resource.Prop_Id, user.Id }
                    }
                });
            }
        }

Get groups the current user is a direct member of ,you could try :

IUserMemberOfCollectionWithReferencesPage memberOfGroups = await graphClient.Users["testnanyu@testbasic1.onmicrosoft.com"].MemberOf.Request().GetAsync();

            if (memberOfGroups?.Count > 0)
            {
                foreach (var directoryObject in memberOfGroups)
                {

                    // We only want groups, so ignore DirectoryRole objects.
                    if (directoryObject is Group)
                    {
                        Group group = directoryObject as Group;
                        items.Add(new ResultsItem
                        {
                            Display = group.DisplayName,
                            Id = group.Id
                        });
                    }

                }
            }