Sending email using Microsoft graph with attachment. Microsoft code example unclear - email

Question

HI I am trying to use Microsoft graph api to send messages.
Previously, I was sending messages/emails with the graph api without attachment. Now I need to attach 10 attachment each.
So I looked for examples and got to the Microsoft document and it shows the following code
GraphServiceClient graphClient = new GraphServiceClient( authProvider );
var attachment = new FileAttachment
{
Name = "smile",
ContentBytes = Convert.FromBase64String("R0lGODdhEAYEAA7")
};
await graphClient.Me.Messages["{message-id}"].Attachments
.Request()
.AddAsync(attachment);
Link:
https://learn.microsoft.com/en-us/graph/api/message-post-attachments?view=graph-rest-1.0&tabs=csharp
My question is what it is showing is not clear I am not sure I would I use message-id. Also I dont see if the Message is created and how the attachment is created.
Can someone help please.

Answer 1

You may refer to this document to learn the example about how to send email with attachments. And the below is my test code, it worked for me, I used client credential flow to provide authentication..
using Azure.Identity;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Graph;
public class HomeController : Controller
{
private readonly IWebHostEnvironment _appEnvironment;
public HomeController(IWebHostEnvironment appEnvironment)
{
_appEnvironment = appEnvironment;
}
public async Task<string> sendMailAsync() {
var scopes = new[] { "https://graph.microsoft.com/.default" };
var tenantId = "your_tenant_name.onmicrosoft.com";
var clientId = "azure_ad_clientid";
var clientSecret = "client_secret";
var clientSecretCredential = new ClientSecretCredential(
tenantId, clientId, clientSecret);
var graphClient = new GraphServiceClient(clientSecretCredential, scopes);
var a = _appEnvironment.WebRootPath;//I have a file stored in my project
var file = a + "\\hellow.txt";
byte[] fileArray = System.IO.File.ReadAllBytes(#file);
//string base64string = Convert.ToBase64String(fileArray);
var message = new Message
{
Subject = "Meet for lunch?",
Body = new ItemBody
{
ContentType = BodyType.Text,
Content = "The new cafeteria is open."
},
ToRecipients = new List<Recipient>()
{
new Recipient
{
EmailAddress = new EmailAddress
{
Address = "xxx#outlook.com"
}
}
},
Attachments = new MessageAttachmentsCollectionPage()
{
new FileAttachment
{
Name = "attachment.txt",
ContentType = "text/plain",
ContentBytes = fileArray
}
}
};
await graphClient.Users["user_id"]
.SendMail(message, null)
.Request()
.PostAsync();
return "success";
}
}