Retrieve Email from IMAP4 server in VB.NET¶

In previous section, I introduced retrieving email from POP3 server in VB.NET. In this section, I will introduce the IMAP4 server.

Sections:

Introduction
[VB.NET Example - Retrieve email from IMAP4 inbox]
[VB.NET Example - Retrieve email from “Deleted Items”]
TLS 1.2

Introduction¶

IMAP4 protocol is different with POP3 protocol. First of all, IMAP4 supports retrieving email from different mail folder and folder management. Secondly, IMAP4 supports mail flags management. Therefore, we can do more things with IMAP4 server. To better understand the IMAP4 protocol, please see the following examples.

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 IMAP4 inbox]¶

The following example codes demonstrate how to download email from IMAP4 server default mailbox. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

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

Imports System.Globalization
Imports System.Text
Imports System.IO
Imports EAGetMail 'imports EAGetMail namespace

Module Module1

    Function _generateFileName(ByVal sequence As Integer) As String
        Dim currentDateTime As DateTime = DateTime.Now
        Return String.Format("{0}-{1:000}-{2:000}.eml",
                            currentDateTime.ToString("yyyyMMddHHmmss", New CultureInfo("en-US")),
                            currentDateTime.Millisecond,
                            sequence)
    End Function

    Sub Main()

        Try
            ' Create a folder named "inbox" under current directory
            ' to save the email retrieved.
            Dim localInbox As String = String.Format("{0}\inbox", Directory.GetCurrentDirectory())

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

            Dim oServer As New MailServer("imap.emailarchitect.net",
                        "test@emailarchitect.net",
                        "testpassword",
                        ServerProtocol.Imap4)

            ' Enable SSL/TLS connection, most modern email server require SSL/TLS connection by default.
            oServer.SSLConnection = True
            oServer.Port = 993

            ' If your server doesn't support SSL/TLS connection, please use the following codes
            ' oServer.SSLConnection = False
            ' oServer.Port = 143

            Console.WriteLine("Connecting server ...")

            Dim oClient As New MailClient("TryIt")
            oClient.Connect(oServer)

            Dim infos As MailInfo() = oClient.GetMailInfos()
            Console.WriteLine("Total {0} email(s)", infos.Length)

            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)

                ' Retrieve email from IMAP 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 unqiue email file name based on date time.
                Dim fileName As String = _generateFileName(i + 1)
                Dim fullPath As String = String.Format("{0}\{1}", localInbox, fileName)

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

                ' Mark email as deleted from IMAP server.
                oClient.Delete(info)

            Next

            ' Quit and expunge emails marked as deleted from IMAP server.
            oClient.Quit()
            Console.WriteLine("Completed!")

        Catch ep As Exception
            Console.WriteLine(ep.Message)
        End Try

    End Sub
End Module

Because IMAP4 protocol supports folder access, so we can retrieve email from other mailbox rather than default “INBOX”. POP3 protocol doesn’t support this feature.

[VB.NET Example - Retrieve email from “Deleted Items”]¶

The following example codes demonstrate how to retrieve emails from “Deleted Items” in an IMAP4 account. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

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

Imports System.Globalization
Imports System.Text
Imports System.IO
Imports EAGetMail 'imports EAGetMail namespace

Module Module1

    ' if you want to search sub folder, use parentfolder\subfolder as folderPath
    ' for example: inbox\mysubfolder
    Function FindFolder(ByVal folderPath As String, ByRef folders As Imap4Folder()) As Imap4Folder
        For i As Integer = 0 To folders.Length - 1
            Dim folder As Imap4Folder = folders(i)
            ' Folder was found.
            If String.Compare(folder.LocalPath, folderPath, True) = 0 Then
                Return folder
            End If

            folder = FindFolder(folderPath, folder.SubFolders)
            If Not (folder Is Nothing) Then
                Return folder
            End If
        Next

        ' No folder found
        Return Nothing
    End Function

    Function _generateFileName(ByVal sequence As Integer) As String
        Dim currentDateTime As DateTime = DateTime.Now
        Return String.Format("{0}-{1:000}-{2:000}.eml",
                            currentDateTime.ToString("yyyyMMddHHmmss", New CultureInfo("en-US")),
                            currentDateTime.Millisecond,
                            sequence)
    End Function

    Sub Main()

        Try
            ' Create a folder named "inbox" under current directory
            ' to save the email retrieved.
            Dim localInbox As String = String.Format("{0}\inbox", Directory.GetCurrentDirectory())

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

            Dim oServer As New MailServer("imap.emailarchitect.net",
                        "test@emailarchitect.net",
                        "testpassword",
                        ServerProtocol.Imap4)

            ' Enable SSL/TLS connection, most modern email server require SSL/TLS connection by default.
            oServer.SSLConnection = True
            oServer.Port = 993

            ' If your server doesn't support SSL/TLS connection, please use the following codes
            ' oServer.SSLConnection = False
            ' oServer.Port = 143

            Console.WriteLine("Connecting server ...")

            Dim oClient As New MailClient("TryIt")
            oClient.Connect(oServer)

            ' Lookup folder based on path.
            Dim folder As Imap4Folder = FindFolder("Deleted Items", oClient.GetFolders())
            If folder Is Nothing Then
                Throw New Exception("Folder was not found")
            End If

            ' Select this folder
            oClient.SelectFolder(folder)

            Dim infos As MailInfo() = oClient.GetMailInfos()
            Console.WriteLine("Total {0} email(s)", infos.Length)

            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)

                ' Retrieve email from IMAP 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 unqiue email file name based on date time.
                Dim fileName As String = _generateFileName(i + 1)
                Dim fullPath As String = String.Format("{0}\{1}", localInbox, fileName)

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

                ' Mark email as deleted from IMAP server.
                oClient.Delete(info)

            Next

            ' Quit and expunge emails marked as deleted from IMAP server.
            oClient.Quit()
            Console.WriteLine("Completed!")

        Catch ep As Exception
            Console.WriteLine(ep.Message)
        End Try

    End Sub
End Module

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 retrieve email from Exchange Server with Web Service protocol.

Tutorial Index

Retrieve Email from IMAP4 server in VB.NET¶

Introduction¶

[VB.NET Example - Retrieve email from IMAP4 inbox]¶

[VB.NET Example - Retrieve email from “Deleted Items”]¶

TLS 1.2¶

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