Downloading attachments with in sub folders using graph api and C#

Question

I'm creating a solution to download attachments from an outlook365 account. The inbox of this account has subfolders and folders within the subfolders. The structure looks like below.

I've been trying to download the attachments but I'm only able to get the attachment from the messages in the main inbox.

But I want to look into the subfolders. So by studying the Microsoft graph document (https://learn.microsoft.com/en-us/graph/api/attachment-get?view=graph-rest-1.0&tabs=http#http-request) I found the below HTTP URL request.

GET /me/mailFolders/{id}/childFolders/{id}/.../messages/{id}/attachments/{id}
GET /users/{id | userPrincipalName}/mailFolders/{id}/childFolders/{id}/messages/{id}/attachments/{id}

GET /me/mailFolders/{id}/childFolders/{id}/.../messages/{id}/attachments/{id}/$value
GET /users/{id | userPrincipalName}/mailFolders/{id}/childFolders/{id}/messages/{id}/attachments/{id}/$value

I'm pretty new to C# I'm having a hard time converting above mentioned URL method to C#. Below is the current code I use to grab the messages and expand the attachments.

public static async Task<IMailFolderMessagesCollectionPage> GetAttachmentToday()
    {
        var DateToDay = DateTime.Now.ToString("dd.MM.yyyy");

        var SearchOption = new List<QueryOption>
        {
            new QueryOption("search", $"%22received:{DateToDay}%22")
        };

        try
        {
            var attachments = await graphClient.Me.MailFolders.Inbox.Messages
                .Request(SearchOption)
                .Top(5)
                .Select(a => new
                {
                    a.Subject,
                    a.HasAttachments
                })
                .Expand("attachments")
                .GetAsync();

            return attachments;
        }
        catch(ServiceException ex)
        {
            Console.WriteLine($"Error getting events: {ex.Message}");
            return null;
        }
    }

I can't figure out how to implement the Microsoft document URL suggestion to work with var attachments = await graphClient.Me.MailFolders.Inbox.Messages. Hope someone can point me down the right path.

Answer 1

I figure this out and used the example HTML code given by Microsoft documents. Which is below.

GET /me/mailFolders/{id}/childFolders/{id}/.../messages/{id}/attachments/{id}
GET /users/{id | userPrincipalName}/mailFolders/{id}/childFolders/{id}/messages/{id}/attachments/{id}

GET /me/mailFolders/{id}/childFolders/{id}/.../messages/{id}/attachments/{id}/$value
GET /users/{id | userPrincipalName}/mailFolders/{id}/childFolders/{id}/messages/{id}/attachments/{id}/$value

So based on the above code I came up with the below C# code.

//To get the first supfolder and it's ID.
var FirstSubFolderIDs = await graphClient.Me.MailFolders["Inbox"].ChildFolders
                    .Request()
                    .Select(fid => new
                    {
                        fid.Id,
                        fid.DisplayName
                    })
                    .GetAsync();
                
                foreach(var FirstSubFolderID in FirstSubFolderIDs)
                {
                    if(FirstSubFolderID.Id != null)
                    {   //Using the above ID to get the second folder and it's ID.
                        var SecondSubFolderIDs = await graphClient.Me.MailFolders["Inbox"]
                            .ChildFolders[$"{FirstSubFolderID.Id}"]
                            .ChildFolders
                            .Request()
                            .Select(sid => new
                            {
                                sid.Id,
                                sid.DisplayName
                            })
                            .GetAsync();

                        foreach (var SecondSubFolderID in SecondSubFolderIDs)
                        {
                            if(SecondSubFolderID.Id != null)
                            {   //Continuing on using the first 2 ID's to get the 3rd folder and it's ID.
                                var ThirdSubFolderIDs = await graphClient.Me.MailFolders["Inbox"]
                                    .ChildFolders[$"{FirstSubFolderID.Id}"]
                                    .ChildFolders[$"{SecondSubFolderID.Id}"]
                                    .ChildFolders
                                    .Request()
                                    .Select(tid => new
                                    {
                                        tid.Id,
                                        tid.DisplayName,
                                    })
                                    .GetAsync();               

                                foreach (var ThirdSubFolderID in ThirdSubFolderIDs)
                                {
                                    if(ThirdSubFolderID.DisplayName == "New")
                                    {   //Now you're at the last folder where the emails are at.
                                        var GetMessageAttachments = await graphClient.Me.MailFolders["Inbox"]
                                            .ChildFolders[$"{FirstSubFolderID.Id}"]
                                            .ChildFolders[$"{SecondSubFolderID.Id}"]
                                            .ChildFolders[$"{ThirdSubFolderID.Id}"]
                                            .Messages
                                            //.Request(SearchOption)
                                            .Request()
                                            .Expand("attachments")
                                            .Select(gma => new
                                            {   
                                                gma.Id,
                                                gma.Subject,
                                                gma.HasAttachments,                                               
                                                gma.Attachments
                                            })
                                            .GetAsync();

                                        //Get Message count that includes attachments
                                        var MessageCount = GetMessageAttachments.Count;

                                        if (MessageCount != 0)
                                        {
                                          //Do what you want here
                                        }

Decided to answer my question so someone else might find this helpful.