Download/Retrieve Email from Gmail account in VB.NET

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 VB.NET.

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)

Important

If you got authentication error, you need to enable Allowing less secure apps or Sign in using App Passwords.

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

Note

Remarks: All of examples in this section are based on first section: A simple VB.NET 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.

[VB.NET 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.

Imports System.IO
Imports EAGetMail 'imports EAGetMail namespace

Module Module1
    Sub Main()
        ' Create a folder named "inbox" under current directory
        ' to save the email retrieved.
        Dim curpath As String = Directory.GetCurrentDirectory()
        Dim mailbox As String = [String].Format("{0}\inbox", curpath)

        ' If the folder is not existed, create it.
        If Not Directory.Exists(mailbox) Then
            Directory.CreateDirectory(mailbox)
        End If

        ' Gmail IMAP server is "imap.gmail.com"
        Dim oServer As New MailServer("imap.gmail.com", _
            "gmailid@gmail.com", "yourpassword", ServerProtocol.Imap4 )
        Dim oClient As New MailClient("TryIt")

        ' Enable SSL connection
        oServer.SSLConnection = True

        ' Set IMAP4 SSL port
        oServer.Port = 993

        Try
            oClient.Connect(oServer)
            Dim infos As MailInfo() = oClient.GetMailInfos()
            For i As Integer = 0 To infos.Length - 1
                Dim info As MailInfo = infos(i)
                Console.WriteLine("Index: {0}; Size: {1}; UIDL: {2}", _
                        info.Index, info.Size, info.UIDL)

                ' Receive email from Gmail server
                Dim oMail As Mail = oClient.GetMail(info)

                Console.WriteLine("From: {0}", oMail.From.ToString())
                Console.WriteLine("Subject: {0}" & vbCr & vbLf, oMail.Subject)

                ' Generate an email file name based on date time.
                Dim d As System.DateTime = System.DateTime.Now
                Dim cur As New System.Globalization.CultureInfo("en-US")
                Dim sdate As String = d.ToString("yyyyMMddHHmmss", cur)
                Dim fileName As String = [String].Format("{0}\{1}{2}{3}.eml", _
                    mailbox, sdate, d.Millisecond.ToString("d3"), i)

                ' Save email to local disk
                oMail.SaveAs(fileName, True)

                ' Mark email as deleted in Gmail Account
                oClient.Delete(info)
            Next

            ' Quit and purge emails marked as deleted from Gmail IMAP4 server.
            oClient.Quit()
        Catch ep As Exception
            Console.WriteLine(ep.Message)
        End Try

    End Sub
End Module

Gmail IMAP OAUTH

The Gmail IMAP and SMTP servers have been extended to support authorization via the industry-standard OAuth 2.0 protocol. Using OAUTH protocol, user can do authentication by Gmail Web OAuth instead of inputting user and password directly in application. This way is more secure, but a little bit complex.

Using Gmail IMAP OAUTH

Next Section

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

Appendix

Comments

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