VB.NET - Parse winmail.dat (TNEF)

The following vb.net codes demonstrate how to parse MAPI winmail.dat in email.

When an Outlook user composes and sends a message using either Rich Text Format or HTML Format, Outlook automagically generates a file, winmail.dat, and attaches it to the end of the email. The winmail.dat contains the rich text body and original attachments. To parse winmail.dat (TNEF stream) file, we should use DecodeTNEF method.


Before you can use the following sample codes, you should download the EAGetMail Installer and install it on your machine at first. Full sample projects are included in this installer.

Install from NuGet

You can also install the run-time assembly by NuGet. Run the following command in the NuGet Package Manager Console:

Install-Package EAGetMail


If you install it by NuGet, no sample projects are installed, only .NET assembly is installed.

Add reference

To use EAGetMail POP3 & IMAP Component in your project, the first step is “Add reference of EAGetMail to your project”. Please create or open your project with Visual Studio, then go to menu -> Project -> Add Reference -> .NET -> Browse..., and select Installation path\Lib\[netversion]\EAGetMail.dll, click Open-> OK, the reference will be added to the project, you can start to use it to retrieve email and parse email in your project.

add reference in c#/vb.net/managed c++/cli

.NET assembly

Because EAGetMail has separate builds for .Net Framework, please refer to the following table and choose the correct dll.

Separate builds of run-time assembly for .Net Framework 2.0, 4.0, 4.5, 4.6.1, 4.7.2, 4.8.1, .NET 6.0, NET 7.0, .NET 8.0, .NET Standard 2.0 and .Net Compact Framework 2.0, 3.5.

File .NET Framework Version
Lib\net20\EAGetMail.dll Built with .NET Framework 2.0
It requires .NET Framework 2.0, 3.5 or later version.
Lib\net40\EAGetMail.dll Built with .NET Framework 4.0
It requires .NET Framework 4.0 or later version.
Lib\net45\EAGetMail.dll Built with .NET Framework 4.5
It requires .NET Framework 4.5 or later version.
Lib\net461\EAGetMail.dll Built with .NET Framework 4.6.1
It requires .NET Framework 4.6.1 or later version.
Lib\net472\EAGetMail.dll Built with .NET Framework 4.7.2
It requires .NET Framework 4.7.2 or later version.
Lib\net481\EAGetMail.dll Built with .NET Framework 4.8.1
It requires .NET Framework 4.8.1 or later version.
Lib\net6.0\EAGetMail.dll Built with .NET 6.0
It requires .NET 6.0 or later version.
Lib\net7.0\EAGetMail.dll Built with .NET 7.0
It requires .NET 7.0 or later version.
Lib\net8.0\EAGetMail.dll Built with .NET 8.0
It requires .NET 8.0 or later version.
Lib\netstandard2.0\EAGetMail.dll Built with .NET Standard 2.0
It requires .NET Standard 2.0 or later version.
Lib\net20-cf\EAGetMail.dll Built with .NET Compact Framework 2.0
It requires .NET Compact Framework 2.0, 3.5 or later version.
Lib\net35-cf\EAGetMail.dll Built with .NET Compact Framework 3.5
It requires .NET Compact Framework 3.5 or later version.

VB.NET - Parse winmail.dat (TNEF) - example

The following example codes demonstrate parsing winmail.dat - TNEF stream.

In order to run it correctly, please change email server, user, password, folder, file name value to yours.


To get full sample projects, please download and install EAGetMail on your machine.

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

Module Module1
    Private Sub ParseEmail(ByVal emlFile As String)
        Dim oMail As New Mail("TryIt")
        oMail.Load(emlFile, False)

        If oMail.IsEncrypted Then
                ' This email is encrypted, we decrypt it by user default certificate.
                ' you can also use specified certificate like this
                ' Dim oCert As New Certificate()
                ' oCert.Load("c:\test.pfx", "pfxpassword", _
                ' Certificate.CertificateKeyLocation.CRYPT_USER_KEYSET)
                ' oMail = oMail.Decrypt(oCert)
                oMail = oMail.Decrypt(Nothing)
            Catch ep As Exception
            End Try
        End If

        If oMail.IsSigned Then
                ' This email is digital signed.
                Dim signerCert As Certificate = oMail.VerifySignature()
                ' You can add the certificate to your certificate storage like this
                ' signerCert.AddToStore(
                '  Certificate.CertificateStoreLocation.CERT_SYSTEM_STORE_CURRENT_USER,
                '  "addressbook")
                ' Then you can use send the encrypted email back to this sender.
                Console.WriteLine("This email contains a valid digital signature.")
            Catch ep As Exception
            End Try
        End If

        ' Decode winmail.dat (TNEF) and RTF body automatically

        ' Parse Mail From/Sender
        Console.WriteLine("From: {0}", oMail.From.ToString())

        ' Parse Mail To/Recipient
        Dim addrs As MailAddress() = oMail.[To]
        For i As Integer = 0 To addrs.Length - 1
            Console.WriteLine("To: {0}", addrs(i).ToString())

        ' Parse Mail CC
        addrs = oMail.Cc
        For i As Integer = 0 To addrs.Length - 1
            Console.WriteLine("To: {0}", addrs(i).ToString())

        ' Parse Mail Subject
        Console.WriteLine("Subject: {0}", oMail.Subject)

        ' Parse Mail Text/Plain body
        Console.WriteLine("TextBody: {0}", oMail.TextBody)

        ' Parse Mail Html Body
        Console.WriteLine("HtmlBody: {0}", oMail.HtmlBody)

        ' Parse Attachments
        Dim atts As Attachment() = oMail.Attachments
        For i As Integer = 0 To atts.Length - 1
            Dim att As Attachment = atts(i)
            Console.WriteLine("Attachment: {0}", att.Name)
    End Sub

    Sub Main()
            ParseEmail("c:\my folder\test.eml")
        Catch ex As Exception
        End Try

    End Sub
End Module



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