Download/Retrieve Email from Gmail account in C#¶

In previous section, I introduced how to retrieve email over SSL connection. In this section, I will introduce how to download email from your Gmail account in C#.

Sections:

Introduction
Gmail App Password
[C# Example - Retrieve email from Gmail account]
Gmail IMAP OAUTH
[C# Example - Retrieve Unread/New Email from Gmail Account]
TLS 1.2

Introduction¶

Gmail POP3 server address is pop.gmail.com. It requires SSL connection on 995 port, and you should use your Gmail email address as the user name for user authentication.

Gmail IMAP4 server address is imap.gmail.com. It requires SSL connection on 993 port, and you should use your Gmail email address as the user name for user authentication. For example: your email is gmailid@gmail.com, and then the user name should be gmailid@gmail.com.

To retrieve email from Gmail account, you need to enable POP3 or IMAP4 access in your gmail account settings.

Because Gmail POP3 server doesn’t work like normal POP3 server, it hides old emails automatically even the email was not deleted, so we suggest that you use IMAP4 protocol.

Server	Port	SSL	Protocol
pop.gmail.com	995	SSL required	Pop3
imap.gmail.com	993	SSL required	Imap4 (recommended)

Gmail App Password¶

To help keep your account secure, starting May 30, 2022, Google will no longer support the use of third-party apps or devices which ask you to sign in to your Google Account using only your username and password.

Therefore, you should sign in using App Passwords. An App Password is a 16-digit passcode that gives a less secure app or device permission to access your Google Account. App Passwords can only be used with accounts that have 2-Step Verification turned on. You need to use App Password instead of the user password for user authentication.

Another solution is Gmail OAUH, please see Gmail IMAP OAUTH section.

Note

Remarks: All of examples in this section are based on first section: A simple C# project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference to your project.

[C# Example - Retrieve email from Gmail account]¶

The following example codes demonstrate how to download email from Gmail account using IMAP4 protocol.

Because Gmail POP3 server doesn’t work like normal POP3 server, it hides old emails automatically even the email was not deleted, so we suggest that you use IMAP4 protocol.

Note

To get the full sample projects, please refer to Samples section.

using System;
using System.Globalization;
using System.IO;
using EAGetMail; //add EAGetMail namespace

namespace receiveemail
{
    class Program
    {
        // Generate an unqiue email file name based on date time
        static string _generateFileName(int sequence)
        {
            DateTime currentDateTime = DateTime.Now;
            return string.Format("{0}-{1:000}-{2:000}.eml",
                currentDateTime.ToString("yyyyMMddHHmmss", new CultureInfo("en-US")),
                currentDateTime.Millisecond,
                sequence);
        }

        static void Main(string[] args)
        {
            try
            {
                // Create a folder named "inbox" under current directory
                // to save the email retrieved.
                string localInbox = string.Format("{0}\\inbox", Directory.GetCurrentDirectory());
                // If the folder is not existed, create it.
                if (!Directory.Exists(localInbox))
                {
                    Directory.CreateDirectory(localInbox);
                }

                // Create app password in Google account
                // https://support.google.com/accounts/answer/185833?hl=en
                // Gmail IMAP4 server is "imap.gmail.com"
                MailServer oServer = new MailServer("imap.gmail.com",
                                "gmailid@gmail.com",
                                "your app password",
                                ServerProtocol.Imap4);

                // Enable SSL connection.
                oServer.SSLConnection = true;

                // Set 993 SSL port
                oServer.Port = 993;

                MailClient oClient = new MailClient("TryIt");
                oClient.Connect(oServer);

                MailInfo[] infos = oClient.GetMailInfos();
                Console.WriteLine("Total {0} email(s)\r\n", infos.Length);
                for (int i = 0; i < infos.Length; i++)
                {
                    MailInfo info = infos[i];
                    Console.WriteLine("Index: {0}; Size: {1}; UIDL: {2}",
                        info.Index, info.Size, info.UIDL);

                    // Receive email from IMAP4 server
                    Mail oMail = oClient.GetMail(info);

                    Console.WriteLine("From: {0}", oMail.From.ToString());
                    Console.WriteLine("Subject: {0}\r\n", oMail.Subject);

                    // Generate an unqiue email file name based on date time.
                    string fileName = _generateFileName(i + 1);
                    string fullPath = string.Format("{0}\\{1}", localInbox, fileName);

                    // Save email to local disk
                    oMail.SaveAs(fullPath, true);

                    // Mark email as deleted from IMAP4 server.
                    oClient.Delete(info);
                }

                // Quit and expunge emails marked as deleted from IMAP4 server.
                oClient.Quit();
                Console.WriteLine("Completed!");
            }
            catch (Exception ep)
            {
                Console.WriteLine(ep.Message);
            }
        }
    }
}

Gmail IMAP OAUTH¶

By default, you can generate an App Passwords, and use this app password instead of the user password for IMAP4 authentication.

However, Google will disable traditional user authentication in the future, switching to Google OAuth is strongly recommended now.

[C# Example - Retrieve Unread/New Email from Gmail Account]¶

Because IMAP/EWS/WebDAV support read mail flag, with this feature, we can also retrieve unread/new email only from Gmail like this

using System;
using System.Globalization;
using System.IO;
using EAGetMail; //add EAGetMail namespace

namespace receiveemail
{
    class Program
    {
        // Generate an unqiue email file name based on date time
        static string _generateFileName(int sequence)
        {
            DateTime currentDateTime = DateTime.Now;
            return string.Format("{0}-{1:000}-{2:000}.eml",
                currentDateTime.ToString("yyyyMMddHHmmss", new CultureInfo("en-US")),
                currentDateTime.Millisecond,
                sequence);
        }

        static void Main(string[] args)
        {
            try
            {
                // Create a folder named "inbox" under current directory
                // to save the email retrieved.
                string localInbox = string.Format("{0}\\inbox", Directory.GetCurrentDirectory());
                // If the folder is not existed, create it.
                if (!Directory.Exists(localInbox))
                {
                    Directory.CreateDirectory(localInbox);
                }

                // Create app password in Google account
                // https://support.google.com/accounts/answer/185833?hl=en
                // Gmail IMAP4 server is "imap.gmail.com"
                MailServer oServer = new MailServer("imap.gmail.com",
                                "gmailid@gmail.com",
                                "your app password",
                                ServerProtocol.Imap4);

                // Enable SSL connection.
                oServer.SSLConnection = true;

                // Set 993 SSL port
                oServer.Port = 993;

                MailClient oClient = new MailClient("TryIt");
                oClient.Connect(oServer);

                // retrieve unread/new email only
                oClient.GetMailInfosParam.Reset();
                oClient.GetMailInfosParam.GetMailInfosOptions = GetMailInfosOptionType.NewOnly;

                MailInfo[] infos = oClient.GetMailInfos();
                Console.WriteLine("Total {0} unread email(s)\r\n", infos.Length);
                for (int i = 0; i < infos.Length; i++)
                {
                    MailInfo info = infos[i];
                    Console.WriteLine("Index: {0}; Size: {1}; UIDL: {2}",
                        info.Index, info.Size, info.UIDL);

                    // Receive email from IMAP4 server
                    Mail oMail = oClient.GetMail(info);

                    Console.WriteLine("From: {0}", oMail.From.ToString());
                    Console.WriteLine("Subject: {0}\r\n", oMail.Subject);

                    // Generate an unqiue email file name based on date time.
                    string fileName = _generateFileName(i + 1);
                    string fullPath = string.Format("{0}\\{1}", localInbox, fileName);

                    // Save email to local disk
                    oMail.SaveAs(fullPath, true);

                    // mark unread email as read, next time this email won't be retrieved again
                    if(!info.Read)
                    {
                        oClient.MarkAsRead(info, true);
                    }

                    // if you don't want to leave a copy on server, please use
                    // oClient.Delete(info);
                    // instead of MarkAsRead
                }

                // Quit and expunge emails marked as deleted from IMAP4 server.
                oClient.Quit();
                Console.WriteLine("Completed!");
            }
            catch (Exception ep)
            {
                Console.WriteLine(ep.Message);
            }
        }
    }
}

TLS 1.2¶

TLS is the successor of SSL, more and more Email servers require TLS 1.2 encryption now.

If your operating system is Windows XP/Vista/Windows 7/Windows 2003/2008/2008 R2/2012/2012 R2, and you got connection error with SSL/TLS connection, you need to enable TLS 1.2 protocol in your operating system like this:

Enable TLS 1.2 on Windows XP/Vista/7/10/Windows 2008/2008 R2/2012

Next Section

At next section I will introduce how to download emails from Yahoo account.

Tutorial Index

Download/Retrieve Email from Gmail account in C#¶

Introduction¶

Gmail App Password¶

[C# Example - Retrieve email from Gmail account]¶

Gmail IMAP OAUTH¶

[C# Example - Retrieve Unread/New Email from Gmail Account]¶

TLS 1.2¶

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