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This guide covers common mail operations including sending messages, reading mail, managing folders, and working with attachments.

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Getting Started

using Microsoft.Graph;
using Microsoft.Graph.Models;
using Microsoft.Graph.Me.SendMail;

var graphClient = new GraphServiceClient(authProvider);

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Sending Mail

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Send a Simple Email

1

Create the message

var message = new Message
{
    Subject = "Hello from Microsoft Graph",
    Body = new ItemBody
    {
        ContentType = BodyType.Text,
        Content = "This is a test email sent using the Microsoft Graph .NET SDK."
    },
    ToRecipients = new List<Recipient>
    {
        new Recipient
        {
            EmailAddress = new EmailAddress
            {
                Address = "[email protected]"
            }
        }
    }
};
2

Send the message

var requestBody = new SendMailPostRequestBody
{
    Message = message,
    SaveToSentItems = true
};

await graphClient.Me.SendMail
    .PostAsync(requestBody);

​
Send HTML Email

var message = new Message
{
    Subject = "HTML Email",
    Body = new ItemBody
    {
        ContentType = BodyType.Html,
        Content = @"
            <html>
                <body>
                    <h1>Welcome!</h1>
                    <p>This is an <strong>HTML</strong> email.</p>
                </body>
            </html>"
    },
    ToRecipients = new List<Recipient>
    {
        new Recipient
        {
            EmailAddress = new EmailAddress
            {
                Address = "[email protected]",
                Name = "John Doe"
            }
        }
    }
};

var requestBody = new SendMailPostRequestBody
{
    Message = message,
    SaveToSentItems = true
};

await graphClient.Me.SendMail
    .PostAsync(requestBody);

​
Send Email with CC and BCC

var message = new Message
{
    Subject = "Project Update",
    Body = new ItemBody
    {
        ContentType = BodyType.Text,
        Content = "Here's the latest update on the project."
    },
    ToRecipients = new List<Recipient>
    {
        new Recipient
        {
            EmailAddress = new EmailAddress { Address = "[email protected]" }
        }
    },
    CcRecipients = new List<Recipient>
    {
        new Recipient
        {
            EmailAddress = new EmailAddress { Address = "[email protected]" }
        },
        new Recipient
        {
            EmailAddress = new EmailAddress { Address = "[email protected]" }
        }
    },
    BccRecipients = new List<Recipient>
    {
        new Recipient
        {
            EmailAddress = new EmailAddress { Address = "[email protected]" }
        }
    },
    Importance = Importance.High
};

var requestBody = new SendMailPostRequestBody
{
    Message = message,
    SaveToSentItems = true
};

await graphClient.Me.SendMail
    .PostAsync(requestBody);

​
Sending Mail with Attachments

​
Add File Attachment

var message = new Message
{
    Subject = "Document for Review",
    Body = new ItemBody
    {
        ContentType = BodyType.Text,
        Content = "Please review the attached document."
    },
    ToRecipients = new List<Recipient>
    {
        new Recipient
        {
            EmailAddress = new EmailAddress { Address = "[email protected]" }
        }
    },
    Attachments = new List<Attachment>
    {
        new FileAttachment
        {
            Name = "report.pdf",
            ContentType = "application/pdf",
            ContentBytes = File.ReadAllBytes("path/to/report.pdf")
        }
    }
};

var requestBody = new SendMailPostRequestBody
{
    Message = message,
    SaveToSentItems = true
};

await graphClient.Me.SendMail
    .PostAsync(requestBody);

​
Add Multiple Attachments

var attachments = new List<Attachment>
{
    new FileAttachment
    {
        Name = "document.docx",
        ContentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
        ContentBytes = File.ReadAllBytes("document.docx")
    },
    new FileAttachment
    {
        Name = "spreadsheet.xlsx",
        ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
        ContentBytes = File.ReadAllBytes("spreadsheet.xlsx")
    }
};

var message = new Message
{
    Subject = "Multiple Files",
    Body = new ItemBody
    {
        ContentType = BodyType.Text,
        Content = "Please find the attached files."
    },
    ToRecipients = new List<Recipient>
    {
        new Recipient
        {
            EmailAddress = new EmailAddress { Address = "[email protected]" }
        }
    },
    Attachments = attachments
};

var requestBody = new SendMailPostRequestBody
{
    Message = message,
    SaveToSentItems = true
};

await graphClient.Me.SendMail
    .PostAsync(requestBody);

​
Reading Mail

​
List Messages in Inbox

var messages = await graphClient.Me.Messages
    .GetAsync(requestConfiguration =>
    {
        requestConfiguration.QueryParameters.Top = 25;
        requestConfiguration.QueryParameters.Orderby = new[] { "receivedDateTime DESC" };
        requestConfiguration.QueryParameters.Select = new[] 
        { 
            "subject", 
            "from", 
            "receivedDateTime",
            "isRead"
        };
    });

foreach (var message in messages.Value)
{
    Console.WriteLine($"{message.Subject} - {message.ReceivedDateTime}");
}

​
Filter Messages

var unreadMessages = await graphClient.Me.Messages
    .GetAsync(requestConfiguration =>
    {
        requestConfiguration.QueryParameters.Filter = "isRead eq false";
    });

​
Get a Single Message

var message = await graphClient.Me.Messages["message-id"]
    .GetAsync();

Console.WriteLine($"Subject: {message.Subject}");
Console.WriteLine($"From: {message.From.EmailAddress.Address}");
Console.WriteLine($"Body: {message.Body.Content}");

​
Managing Messages

​
Mark as Read/Unread

var messageUpdate = new Message
{
    IsRead = true
};

await graphClient.Me.Messages["message-id"]
    .PatchAsync(messageUpdate);

​
Delete a Message

await graphClient.Me.Messages["message-id"]
    .DeleteAsync();

​
Move Message to Folder

var movePostBody = new MovePostRequestBody
{
    DestinationId = "folder-id"
};

await graphClient.Me.Messages["message-id"]
    .Move
    .PostAsync(movePostBody);

​
Reply to Message

1

Create reply

var reply = await graphClient.Me.Messages["message-id"]
    .CreateReply
    .PostAsync();
2

Update reply content

var replyUpdate = new Message
{
    Body = new ItemBody
    {
        ContentType = BodyType.Text,
        Content = "Thank you for your message. I'll get back to you soon."
    }
};

await graphClient.Me.Messages[reply.Id]
    .PatchAsync(replyUpdate);
3

Send the reply

await graphClient.Me.Messages[reply.Id]
    .Send
    .PostAsync();

​
Forward Message

var forwardPostBody = new ForwardPostRequestBody
{
    Comment = "FYI - please review this.",
    ToRecipients = new List<Recipient>
    {
        new Recipient
        {
            EmailAddress = new EmailAddress
            {
                Address = "[email protected]"
            }
        }
    }
};

await graphClient.Me.Messages["message-id"]
    .Forward
    .PostAsync(forwardPostBody);

​
Working with Mail Folders

​
List All Folders

var folders = await graphClient.Me.MailFolders
    .GetAsync();

foreach (var folder in folders.Value)
{
    Console.WriteLine($"{folder.DisplayName} ({folder.UnreadItemCount} unread)");
}

​
Create a Custom Folder

var newFolder = new MailFolder
{
    DisplayName = "Project Alpha"
};

var createdFolder = await graphClient.Me.MailFolders
    .PostAsync(newFolder);

​
Get Messages from Specific Folder

var messages = await graphClient.Me.MailFolders["folder-id"]
    .Messages
    .GetAsync();

​
Working with Attachments

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List Message Attachments

var attachments = await graphClient.Me.Messages["message-id"]
    .Attachments
    .GetAsync();

foreach (var attachment in attachments.Value)
{
    if (attachment is FileAttachment fileAttachment)
    {
        Console.WriteLine($"File: {fileAttachment.Name}");
        Console.WriteLine($"Size: {fileAttachment.Size} bytes");
    }
}

​
Download Attachment

var attachment = await graphClient.Me.Messages["message-id"]
    .Attachments["attachment-id"]
    .GetAsync();

if (attachment is FileAttachment fileAttachment)
{
    var fileBytes = fileAttachment.ContentBytes;
    await File.WriteAllBytesAsync(fileAttachment.Name, fileBytes);
    Console.WriteLine($"Downloaded: {fileAttachment.Name}");
}

​
Complete Example

using Microsoft.Graph;
using Microsoft.Graph.Models;
using Microsoft.Graph.Models.ODataErrors;

public class MailManager
{
    private readonly GraphServiceClient _graphClient;

    public MailManager(GraphServiceClient graphClient)
    {
        _graphClient = graphClient;
    }

    public async Task SendEmailWithRetryAsync(
        string to,
        string subject,
        string body,
        List<string> attachmentPaths = null)
    {
        var message = new Message
        {
            Subject = subject,
            Body = new ItemBody
            {
                ContentType = BodyType.Html,
                Content = body
            },
            ToRecipients = new List<Recipient>
            {
                new Recipient
                {
                    EmailAddress = new EmailAddress { Address = to }
                }
            }
        };

        // Add attachments if provided
        if (attachmentPaths?.Any() == true)
        {
            message.Attachments = new List<Attachment>();
            
            foreach (var path in attachmentPaths)
            {
                var fileName = Path.GetFileName(path);
                var contentBytes = await File.ReadAllBytesAsync(path);
                
                message.Attachments.Add(new FileAttachment
                {
                    Name = fileName,
                    ContentBytes = contentBytes
                });
            }
        }

        var requestBody = new SendMailPostRequestBody
        {
            Message = message,
            SaveToSentItems = true
        };

        try
        {
            await _graphClient.Me.SendMail
                .PostAsync(requestBody);
            
            Console.WriteLine("Email sent successfully!");
        }
        catch (ODataError error)
        {
            Console.WriteLine($"Failed to send email: {error.Error.Message}");
            throw;
        }
    }

    public async Task ProcessUnreadEmailsAsync()
    {
        var messages = await _graphClient.Me.Messages
            .GetAsync(config =>
            {
                config.QueryParameters.Filter = "isRead eq false";
                config.QueryParameters.Top = 50;
                config.QueryParameters.Orderby = new[] { "receivedDateTime DESC" };
            });

        foreach (var message in messages.Value)
        {
            Console.WriteLine($"Processing: {message.Subject}");
            
            // Mark as read
            var update = new Message { IsRead = true };
            await _graphClient.Me.Messages[message.Id]
                .PatchAsync(update);

            // Download attachments
            var attachments = await _graphClient.Me.Messages[message.Id]
                .Attachments
                .GetAsync();

            foreach (var attachment in attachments.Value)
            {
                if (attachment is FileAttachment fileAttachment)
                {
                    await File.WriteAllBytesAsync(
                        Path.Combine("downloads", fileAttachment.Name),
                        fileAttachment.ContentBytes
                    );
                }
            }
        }
    }

    public async Task<MailFolder> CreateAndOrganizeFolderAsync(
        string folderName,
        string fromAddress)
    {
        // Create folder
        var newFolder = new MailFolder
        {
            DisplayName = folderName
        };

        var folder = await _graphClient.Me.MailFolders
            .PostAsync(newFolder);

        // Move messages from specific sender to new folder
        var messages = await _graphClient.Me.Messages
            .GetAsync(config =>
            {
                config.QueryParameters.Filter = 
                    $"from/emailAddress/address eq '{fromAddress}'";
            });

        foreach (var message in messages.Value)
        {
            var moveBody = new MovePostRequestBody
            {
                DestinationId = folder.Id
            };

            await _graphClient.Me.Messages[message.Id]
                .Move
                .PostAsync(moveBody);
        }

        return folder;
    }
}

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Next Steps

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