VB.NET - Export emails from Outlook PST file to RFC822 message files (*.eml)¶

Imports Outlook = Microsoft.Office.Interop.Outlook
Imports System.Runtime.InteropServices
Imports EAGetMail
Imports System.IO

Module Module1

    ' Export emails from Outlook folder/PST file to rfc822 message files.
    Sub ExportMailItemToRfc822(ByRef folder As Outlook.Folder, ByVal destFolder As String)
        Dim items = folder.Items
        For i As Integer = 1 To items.Count
            Dim mailItem = CType(items(i), Outlook.MailItem)

            Dim tempMsgFile As String = String.Format("{0}\temp_{1}.msg", destFolder, i)
            mailItem.SaveAs(tempMsgFile, Outlook.OlSaveAsType.olMSGUnicode)

            Dim mail = New EAGetMail.Mail("TryIt")
            mail.LoadOMSG(tempMsgFile)
            mail.Update()

            Dim rfc822MessageFile As String = String.Format("{0}\rfc822_{1}.eml", destFolder, i)
            mail.SaveAs(rfc822MessageFile, True)

            File.Delete(tempMsgFile)
        Next
    End Sub

    Sub Main()

        Dim app = New Outlook.Application()
        Dim folder = app.GetNamespace("MAPI").
            GetDefaultFolder(Outlook.OlDefaultFolders.olFolderInbox)

        ' If you want to export emails from
        ' existed PST file, you can use the following codes.
        ' app.Session.AddStore("d:\tempFolder\test.pst");
        ' Dim folder = app.GetNamespace("MAPI").Folders.GetLast()

        ExportMailItemToRfc822(folder, "d:\destFolder")

        app.Quit()
    End Sub

End Module