Bugs in System.Net.Mail.MailMessage (.NET 2.0 SP1)

Question

Some time ago I reported about bugs in System.Net.Mail.MailMessage (.NET 2.0), hoping for a fix in SP1 of .NET 2.0. Well, unfortunately most of them still exist.

1. With MailMessage.Headers there is a bug where headers will have white space in an encoded text. This will lead to non-RFC2047 compliant messages, which will increase the SPAM rating of the message. MailAddresses (also to be considered as headers) are effected as well.
2. Quoted-Printable encoding is not limited to a maximum of 76 characters in System.Net.Mail. RFC2045 requires that Quoted-Printable encoding encodes lines be no more than 76 characters long. If longer lines are to be encoded with the Quoted-Printable encoding, "soft" line breaks must be used.
3. MailMessage.To.ToString() returns the encoded string only after the message was sent. According to the documentation this should be the case no matter whether the message was already sent or not.

As a matter of fact I hacked System.Net.Mail using Reflection, published here (relevant class: Bugfixer.cs).

I consider these bugs very simple to fix, so I'm just wondering what else I could do to make this happen?

Norbert

Answer 1

Said issues are on our radar. We're on track to fix them in an upcoming release. Unfortunately I cannot be more specific than that.

 

and thanks for bringing this to our attention. Again. In fact, you should try again if you don't see this fixed in SP2. These posts are really processed and comes to our attention.

Answer 2

Is there a solution to the quoted printable lines being too long yet? I can't imagine how this has gone un-fixed for years now.

Our application uses the .Net SMTP engine to deliver email alerts to users, and now because of this quoted printable bug, our emails are often marked as spam.

PLEASE tell me this is actually on the radar to be fixed. It was allegedly in 3.5 or 3.5 SP1, but it's still broken. It's not like these email RFC standards are new and a few bugs would be understandable. And now that spam software is looking for this specifically, it's unacceptable that Microsoft would allow their customers to be screwed for using their own built in libraries.

Best Regards,

Kevin Ulland

Answer 3

I'm using .NET 2.0 SP2 and still are making bad quoted-printable encoding. It's still spaces in quoted printable text.
Are there any method or routine for passing my quoted-printable conversion routine for making good quoted-printable encoding?

Answer 4

We plan to address all of these issues in .NET 4.0.

Thx,

David

Answer 5

At what point will the quoted printable line length be addressed?  I have the 4.0 beta framework and it looks like it's still an issue...

Answer 6

The fixes are in .NET 4.0 Beta 2.   The Beta that you were using in July was Beta 1.

Thx,

David

Answer 7

If you don't want to use .NET 4.0 you can use .NET 2.0 but using the methods of that class that "patches" errors.

Option Strict On
Option Explicit On
Imports System.Collections.Generic
Imports System.Text
Imports System.Net.Mail
Imports System.Reflection
Imports System.Net.Mime
Imports System
Imports System.IO

Public Class clsBugFixerSystemNetMail



    


    ''' <summary>
    ''' Corrects a bug in System.Net.Mail of .NET 2.0 before Servicepack 1:
    ''' TransferEncoding.SevenBit turns into header text "sevenbit", instead of "7bit".
    ''' "sevenbit" is not RFC compliant and causes problems with some mail clients. This method
    ''' does the correction.
    ''' </summary>
    ''' <seealso cref="http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=98783&SiteID=1"/>
    ''' <param name="att">all Attachments, AlternateViews und LinkedResources are based on AttachmentBase</param>
    '''(Obsolete("Only needed for .NET 2.0 before Servicepack 1", false))
    Public Shared Sub CorrectSevenBitTransferEncoding(ByVal att As AttachmentBase)
        '' do nothing wiht binary or unknown transfer encoding
        Dim lArgs() As Object
        If ((att Is Nothing) Or (att.TransferEncoding = TransferEncoding.Base64) Or _
            att.TransferEncoding = TransferEncoding.Unknown) Then
            Return
        End If
        If (System.Environment.Version.Major <> 2 Or System.Environment.Version.MajorRevision <> 0 Or _
            System.Environment.Version.Build <> 50727 Or System.Environment.Version.Revision > 900) Then
            If QPEncoder.IsSevenBit(att.ContentStream) Then
                att.TransferEncoding = TransferEncoding.SevenBit
            Else
                att.TransferEncoding = TransferEncoding.QuotedPrintable
            End If
            Return
        End If

        '' Get System.Net.Mime.MimePart:
        Dim mimePart As Object = GetType(System.Net.Mail.AttachmentBase).InvokeMember("part", _
        BindingFlags.DeclaredOnly Or _
        BindingFlags.Public Or BindingFlags.NonPublic Or _
        BindingFlags.Instance Or BindingFlags.GetField, Nothing, att, Nothing)

        '' get fields of mimePart
        Dim fi As FieldInfo() = mimePart.GetType().BaseType.GetFields(BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
          BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Instance)

        '' Get System.Net.Mime.HeaderCollection:
        Dim headerCollection As Object
        headerCollection = mimePart.GetType().BaseType.InvokeMember("headers", _
         BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
         BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Instance Or BindingFlags.GetField, _
         Nothing, mimePart, Nothing)

        '' Get methods of System.Net.Mime.HeaderCollection:
        Dim i As MethodInfo() = headerCollection.GetType().GetMethods(BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
          BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Instance)

        '' System.Net.Mime.HeaderCollection: get buggy header value
        ReDim lArgs(0)
        lArgs(0) = "content-transfer-encoding"
        Dim contentTransferEncoding As String = CType(headerCollection.GetType().InvokeMember("Get", _
         BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
         BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Instance Or _
         BindingFlags.InvokeMethod, Nothing, headerCollection, largs), String)

        '' System.Net.Mime.HeaderCollection: Set buggy value from "sevenbit" to "7bit"
        '' Need to check the string value, because att.TransferEncoding shows TransferEncoding.Unknown
        If (contentTransferEncoding = "sevenbit") Then

            ' set 7bit only, if content really is seven bit
            If (QPEncoder.IsSevenBit(att.ContentStream)) Then
                ReDim lArgs(1)
                lArgs(0) = "content-transfer-encoding"
                lArgs(1) = "7bit"
                headerCollection.GetType().InvokeMember("Set", _
                 BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
                 BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Instance Or _
                 BindingFlags.InvokeMethod, Nothing, headerCollection, lArgs)
                '' att.TransferEncoding will now show TranferEncoding.SevenBit (instead of TransferEncoding.Unknown)

            Else

                att.TransferEncoding = TransferEncoding.QuotedPrintable
                '/*
                '// set 8bit (which is not supported by System.Net.Mail) for 8bit content - not recommended
                'headerCollection.GetType().InvokeMember("Set",
                '	BindingFlags.DeclaredOnly | BindingFlags.FlattenHierarchy |
                '	BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.IgnoreCase | BindingFlags.Instance |
                '	BindingFlags.InvokeMethod, null, headerCollection, new object[] { "content-transfer-encoding", "8bit" });
                '*/
            End If
        End If
    End Sub

    ''' <summary>
    ''' Corrects a bug in System.Net.Mail of .NET 2.0 including .NET 3.5 SP1 released version:
    ''' system.net.mail has a bug where headers will have whitespace in the encoded text.
    ''' This will lead to non-RFC2047 compliant messages, which may lead to SPAM rating of the message.
    ''' See a list of SPAM scores at http://www.oucs.ox.ac.uk/network/smtp/relay/scores.txt.
    ''' 
    ''' 'encoded-word's are designed to be recognized as 'atom's by an RFC 822 parser.  As a consequence, unencoded white space
    ''' characters (such as SPACE and HTAB) are FORBIDDEN within an 'encoded-word'.  For example, the character sequence
    '''		=?iso-8859-1?q?this is some text?=
    ''' would be parsed as four 'atom's, rather than as a single 'atom' (by an RFC 822 parser) or 'encoded-word' (by a parser which understands
    ''' 'encoded-words').  The correct way to encode the string "this is some text" is to encode the SPACE characters as well, e.g.
    '''		=?iso-8859-1?q?this=20is=20some=20text?=
    ''' </summary>
    Public Shared Sub CorrectSubjectEncodedWordRFC2047compliant(ByVal mailMessage As MailMessage)

        Dim largs() As Object
        If (System.Environment.Version.Major <> 2 Or System.Environment.Version.MajorRevision <> 0 Or System.Environment.Version.Build <> 50727) Then
            Return
        End If

        '/* The _mailMessage.Subject cannot be changed directly. So the workaround is as follows:
        ' * 1. Set the subject to null, so that no subject header will be produced
        ' * 2. Add the subject as a header, of course with correct handling of whitespace in the encoded text.
        ' * 
        ' * System.Net.MimeBasePart does the same in an internal static method:
        ' * this.Headers["subject"] = MimeBasePart.EncodeHeaderValue(this.subject, this.subjectEncoding, MimeBasePart.ShouldUseBase64Encoding(this.subjectEncoding));
        ' */

        '' Create an instance of System.Net.Mime.MimePart:
        Dim mimePart As Object = GetType(System.Net.Mail.AttachmentBase).InvokeMember("part", _
        BindingFlags.DeclaredOnly Or _
        BindingFlags.Public Or BindingFlags.NonPublic Or _
        BindingFlags.Instance Or BindingFlags.GetField, Nothing, New Attachment(New System.IO.MemoryStream(New ASCIIEncoding().GetBytes(String.Empty)), "dummy"), Nothing)

        Dim subject As String = mailMessage.Subject

        ReDim largs(0)
        largs(0) = mailMessage.SubjectEncoding
        Dim ShouldUseBase64Encoding As Boolean = Convert.ToBoolean(mimePart.GetType().BaseType.InvokeMember("ShouldUseBase64Encoding", _
         BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
         BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Static Or BindingFlags.InvokeMethod, _
         Nothing, mimePart, largs))

        ReDim largs(2)
        largs(0) = subject
        largs(1) = mailMessage.SubjectEncoding
        largs(2) = ShouldUseBase64Encoding
        subject = mimePart.GetType().BaseType.InvokeMember("EncodeHeaderValue", _
         BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
         BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Static Or BindingFlags.InvokeMethod, _
         Nothing, mimePart, largs).ToString()

        '' Bug fix: this bug fix will only work, if ToggleMailHeaderInfoTypeForSubject() is applied before SmtpClient.Send() !
        mailMessage.Subject = Nothing
        mailMessage.Headers.Remove("Subject")
        mailMessage.Headers.Add("Subject", subject.Replace(" ", "=20"))
    End Sub

    ''' <summary>
    ''' Helps to correct a bug in System.Net.Mail of .NET 2.0 including .NET 3.5 released version:
    ''' This is a helper function for CorrectSubjectEncodedWordRFC2047compliant(MailMessage mailMessage), which
    ''' makes sure that an individual MailMessage.Header["Subject"] will not be removed during SmtpClient.Send().
    ''' To achieve this System.Net.Mail.MailHeaderInfo will be temporarily hacked by renaming
    ''' the known header for "Subject" to "SubjectRemoved", so the individual MailMessage.Header["Subject"]
    ''' will not be found.
    ''' </summary>
    ''' <remarks>
    ''' Remember to call this method again right after SmtpClient.Send(), so that 
    ''' static System.Net.Mail.MailHeaderInfo fields will be restored.
    ''' </remarks>
    ''' <seealso cref="CorrectSubjectEncodedWordRFC2047compliant"/>
    Public Shared Sub ToggleMailHeaderInfoTypeForSubject(ByVal msg As MailMessage, ByVal doSubjectRemove As Boolean)

        Dim largs() As Object
        If (System.Environment.Version.Major <> 2 Or System.Environment.Version.MajorRevision <> 0 Or System.Environment.Version.Build <> 50727 Or System.Environment.Version.Revision <= 900) Then
            Return
        End If

        '' Apply only if the subject has to be processed in a special way (due to its Encoding).
        '' Take care: IT MUST NOT BE RUN, if the MailMessage.Subject is set, because this would produce
        '' an additional MailMessage.Header of "SubjectRemoved" (caused by this method)
        If (doSubjectRemove And Not (String.IsNullOrEmpty(msg.Subject) And msg.Headers.GetValues("Subject") IsNot Nothing)) Then
            Return
        End If

        Dim asm As Assembly = Assembly.GetAssembly(GetType(MailAddress))

        '' Retrieve Types of MailHeaderInfo, used in method PrepareHeaders() of System.Net.Mail.Message
        Dim mailHeaderInfoType As Type = asm.GetType("System.Net.Mail.MailHeaderInfo", False)
        Dim headerInfoType As Type = asm.GetType("System.Net.Mail.MailHeaderInfo+HeaderInfo", False)
        Dim mailHeaderIDtype As Type = asm.GetType("System.Net.Mail.MailHeaderID", False)

        '' Invoke System.Net.Mail.MailHeaderInfo.GetString(MailHeaderID id)
        '' in order to make sure that privat fields will be set by its constructor
        Dim mailHeaderInfoMethodInfo As MethodInfo = mailHeaderInfoType.GetMethod("GetString", BindingFlags.Static Or BindingFlags.NonPublic)
        ReDim largs(0)
        largs(0) = 2
        mailHeaderInfoMethodInfo.Invoke(Nothing, largs)

        '' get array HeaderInfo[] m_HeaderInfo = new HeaderInfo[] { new HeaderInfo(MailHeaderID.Bcc, "Bcc", true), ... }
        '' HeaderInfo is a structure with: string NormalizedName, bool IsSingleton, (enum) MailHeaderID ID;
        Dim headerInfo As FieldInfo = mailHeaderInfoType.GetField("m_HeaderInfo", BindingFlags.Static Or BindingFlags.NonPublic)
        Dim headerInfoArray As Array = CType(headerInfo.GetValue(Nothing), Array)

        '' find the HeaderInfo for "Subject" and set the NormalizedName to "SubjectRemoved" (or vice versa)
        Dim i As Integer = 0
        Do
            Dim normalizedNameInfo As FieldInfo = _
            headerInfoType.GetField("NormalizedName", BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.Instance Or BindingFlags.GetField)
            If Not (i < headerInfoArray.Length - 1) Then
                Exit Do
            End If

            If (CType(normalizedNameInfo.GetValue(headerInfoArray.GetValue(i)), String) = "Subject") And doSubjectRemove Then
                ReDim largs(2)
                largs(0) = mailHeaderIDtype.GetField("Subject").GetValue(mailHeaderIDtype)
                largs(1) = "SubjectRemoved"
                largs(2) = True
                Dim headerInfoItem As Object = Activator.CreateInstance(headerInfoType, largs)
                headerInfoArray.SetValue(headerInfoItem, i)
            ElseIf (CType(normalizedNameInfo.GetValue(headerInfoArray.GetValue(i)), String) = "SubjectRemoved" And (Not doSubjectRemove)) Then
                ReDim largs(2)
                largs(0) = mailHeaderIDtype.GetField("Subject").GetValue(mailHeaderIDtype)
                largs(1) = "Subject"
                largs(2) = True
                Dim headerInfoItem As Object = Activator.CreateInstance(headerInfoType, largs)
                headerInfoArray.SetValue(headerInfoItem, i)
            End If

            i += 1
        Loop


        ''now set "Subject" item of Dictionary<string, int> m_HeaderDictionary also to "SubjectRemoved" (or vice versa)
        Dim headerDictionaryInfo As FieldInfo = mailHeaderInfoType.GetField("m_HeaderDictionary", BindingFlags.Static Or BindingFlags.NonPublic)
        Dim m_HeaderDictionary As Dictionary(Of String, Integer) = CType(headerDictionaryInfo.GetValue(Nothing), Dictionary(Of String, Integer))
        If (m_HeaderDictionary.ContainsKey("Subject") And doSubjectRemove) Then

            '' Rename the key from "Subject" to "SubjectRemoved"
            m_HeaderDictionary.Add("SubjectRemoved", m_HeaderDictionary("Subject"))
            m_HeaderDictionary.Remove("Subject")
        ElseIf (m_HeaderDictionary.ContainsKey("SubjectRemoved") And Not doSubjectRemove) Then

            '' Rename the key from "Subject" to "SubjectRemoved"
            m_HeaderDictionary.Add("Subject", m_HeaderDictionary("SubjectRemoved"))
            m_HeaderDictionary.Remove("SubjectRemoved")
        End If
    End Sub


    ''' <summary>
    ''' Corrects a bug in System.Net.Mail of .NET 2.0 including .NET 3.5 SP1 released version:
    ''' Quoted-Printable encoding is not limited to a maximum of 76 charchters.
    ''' This method does the correction.
    ''' 
    ''' RFC2045: The Quoted-Printable encoding REQUIRES that encoded lines be no more than 76
    ''' characters long.  If longer lines are to be encoded with the Quoted-Printable encoding, "soft" line breaks
    ''' must be used.  An equal sign as the last character on a encoded line indicates such a non-significant ("soft")
    ''' line break in the encoded text.
    ''' The 76 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.
    ''' 
    ''' Behavior of .NET 2.0: Insert "soft" line break after a word that starts before 76th character
    ''' msg.Body = "mailmessage doesn't like veryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryvery long strings";
    '''		result (wrong):
    '''			content-type: text/plain; charset=iso-8859-1
    '''			content-transfer-encoding: quoted-printable
    ''' 		mailmessage doesn't like veryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryveryvery=
    '''			long strings
    ''' 
    '''		correct:
    ''' 		content-type: text/plain; charset=iso-8859-1
    '''			content-transfer-encoding: quoted-printable
    ''' 
    '''			mailmessage doesn't like veryveryveryveryveryveryveryveryveryveryveryveryve=
    '''			ryveryveryveryveryveryveryveryveryveryveryveryveryveryveryvery long strings
    ''' </summary>
    ''' <seealso cref="http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=156052"/>
    ''' <param name="att">all Attachments, AlternateViews und LinkedResources are based on AttachmentBase</param>
    ''' <param name="encoding">Encoding</param>
    Public Shared Sub CorrectQuotedPrintableRFC2045compliant(ByVal att As AttachmentBase, ByVal encoding As Encoding)
        Dim lArgs() As Object


        If (System.Environment.Version.Major <> 2 Or System.Environment.Version.MajorRevision <> 0 Or System.Environment.Version.Build <> 50727) Then
            Return
        End If

        If (att Is Nothing) Then
            Return
        End If

        If (att.TransferEncoding = TransferEncoding.QuotedPrintable) Then

            '' Get System.Net.Mime.MimePart:
            Dim mimePart As Object = GetType(System.Net.Mail.AttachmentBase).InvokeMember("part", _
            BindingFlags.DeclaredOnly Or _
            BindingFlags.Public Or BindingFlags.NonPublic Or _
            BindingFlags.Instance Or BindingFlags.GetField, Nothing, att, Nothing)

            '' Convert the content stream to a well formated MemoryStream
            Dim correctedStream As System.IO.MemoryStream = New System.IO.MemoryStream(encoding.GetBytes( _
             QPEncoder.GetInstance().EncodeString(Stream2String(att.ContentStream, encoding), encoding)))

            '' Set System.Net.Mime.MimePart.stream:
            ReDim lArgs(0)
            lArgs(0) = correctedStream
            mimePart.GetType().InvokeMember("stream", _
             BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
             BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Instance Or BindingFlags.SetField, _
             Nothing, mimePart, lArgs)

            '' Get System.Net.Mime.MimeBasePart.HeaderCollection:
            Dim headerCollection As Object
            headerCollection = mimePart.GetType().BaseType.InvokeMember("headers", _
             BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
             BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Instance Or BindingFlags.GetField, _
             Nothing, mimePart, Nothing)

            '' System.Net.Mime.HeaderCollection: Undo cheating of content-transfer-encoding
            '' note the leading blank in " quoted-printable", which leads to a valid header 
            '' but which is unknown to the .NET framework - so the stream will be sent unchanged.
            '' att.TransferEncoding will show as TransferEncoding.Unknown now - don't care!!
            ReDim lArgs(1)
            lArgs(0) = "content-transfer-encoding"
            lArgs(1) = " quoted-printable"
            headerCollection.GetType().InvokeMember("Set", _
             BindingFlags.DeclaredOnly Or BindingFlags.FlattenHierarchy Or _
             BindingFlags.Public Or BindingFlags.NonPublic Or BindingFlags.IgnoreCase Or BindingFlags.Instance Or _
             BindingFlags.InvokeMethod, Nothing, headerCollection, lArgs)
        End If
    End Sub

    ''' <summary>
    ''' Corrects a bug in System.Net.Mail of .NET 2.0 (including .NET 3.5 SP1 released version):
    ''' system.net.mail has a bug where headers will have whitespace in the encoded text.
    ''' This will lead to non-RFC2047 compliant messages, which may lead to SPAM rating of the message.
    ''' See a list of SPAM scores at http://www.oucs.ox.ac.uk/network/smtp/relay/scores.txt.
    ''' 
    ''' 'encoded-word's are designed to be recognized as 'atom's by an RFC 822 parser.  As a consequence, unencoded white space
    ''' characters (such as SPACE and HTAB) are FORBIDDEN within an 'encoded-word'.  For example, the character sequence
    '''		=?iso-8859-1?q?recipient display name?= 
    ''' would be parsed as four 'atom's, rather than as a single 'atom' (by an RFC 822 parser) or 'encoded-word' (by a parser which understands
    ''' 'encoded-words').  The correct way to encode the string "this is some text" is to encode the SPACE characters as well, e.g.
    '''		=?iso-8859-1?q?recipient=20display=20name?=
    ''' </summary>
    ''' <param name="addr">MailAddress</param>
    ''' <param name="encoding">Encoding</param>
    Public Shared Sub CorrectMailAddressEncodedWordRFC2047compliant(ByRef addr As MailAddress, ByVal encoding As Encoding)

        Dim lArgs() As Object

        If (System.Environment.Version.Major <> 2 Or System.Environment.Version.MajorRevision <> 0 Or System.Environment.Version.Build <> 50727) Then
            Return
        End If

        '' enforce encoding only if the address is not completely 7bit or it contains a hyphen
        If (QPEncoder.IsSevenBit(addr.ToString()) = False) Then

            addr = New MailAddress(addr.Address, addr.DisplayName, encoding)

            Dim encodedDisplayName As String = GetType(MailAddress).InvokeMember("encodedDisplayName", _
            BindingFlags.DeclaredOnly Or _
            BindingFlags.Public Or BindingFlags.NonPublic Or _
            BindingFlags.Instance Or BindingFlags.GetField, Nothing, addr, Nothing).ToString()
            ReDim lArgs(0)
            lArgs(0) = encodedDisplayName.Replace(" ", "=20")
            GetType(MailAddress).InvokeMember("encodedDisplayName", _
              BindingFlags.DeclaredOnly Or _
              BindingFlags.Public Or BindingFlags.NonPublic Or _
              BindingFlags.Instance Or BindingFlags.SetField, Nothing, addr, lArgs)

        Else

            If addr.DisplayName.Length > 0 Then
                addr = New MailAddress(addr.Address, addr.DisplayName)
            End If
        End If
    End Sub

    ''' <summary>
    ''' Corrects a bug in System.Net.Mail of .NET 2.0 before Servicepack 1 (equivalent to .NET 3.5 released version):
    ''' With To addresses, displayNameEncoded is never used (with CC, From etc. it is)
    ''' therefore we cannot use the To MailAddress collection of the mail message,
    ''' but instead we set the "to" headers ourselves.
    ''' </summary>
    ''' <param name="toAddr">To MailAddress to add.</param>
    ''' <param name="msg">MailMessage the To address will be added.</param>
    ''' <param name="toHeader">string to be used for the "To" address header</param>
    '''[Obsolete("Only needed and working for .NET 2.0 before Servicepack 1", false)]
    Public Shared Sub AddToAddressWithCorrectEncoding(ByVal toAddr As MailAddress, ByVal msg As MailMessage, ByVal toHeader As String)

        Dim lParam As String
        Dim lStrings() As String
        If (System.Environment.Version.Major <> 2 Or System.Environment.Version.MajorRevision <> 0 Or System.Environment.Version.Build <> 50727 Or System.Environment.Version.Revision > 900) Then
            Return
        End If

        '' Remove the original To address, then add our own envelope header
        msg.To.Remove(toAddr)
        Dim oldTo As String = msg.Headers(toHeader)
        msg.Headers.Remove(toHeader)
        If String.IsNullOrEmpty(oldTo) = True Then
            lParam = String.Empty
        Else
            lParam = ", "
        End If
        ReDim lStrings(1)
        lStrings(0) = oldTo
        lStrings(1) = clsBugFixerSystemNetMail.GetEncodedMailAddress(toAddr)
        msg.Headers.Add(toHeader, String.Join(lParam, lStrings))
        '' SmtpClient wants at least 1 To/CC/Bcc address, so we add the To address as Bcc as well
        msg.Bcc.Add(toAddr)
    End Sub

    ''' <summary>
    ''' Corrects a bug in System.Net.Mail of .NET 2.0 before Servicepack 1 (equivalent to .NET 3.5 released version):
    ''' After MailMessage.MailAddressCollection.Clear erroneously MailAddress is left in message,
    ''' in addition. This function removes the Headers that MailMessage.Clear() does not remove.
    ''' </summary>
    ''' <param name="msg">MailMessage</param>
    '''[Obsolete("Only needed and working for .NET 2.0 before Servicepack 1", false)]
    Public Shared Sub ClearMessageHeaders(ByVal msg As MailMessage)

        If (System.Environment.Version.Major <> 2 Or System.Environment.Version.MajorRevision <> 0 Or System.Environment.Version.Build <> 50727 Or System.Environment.Version.Revision > 900) Then

            Return
        End If

        msg.Headers.Remove("cc")
        msg.Headers.Remove("bcc")
        msg.Headers.Remove("sender")
        msg.Headers.Remove("from")
        msg.Headers.Remove("reply-to")


    End Sub

    ''' <summary>
    ''' Returns a mail address string, which display name is encoded when needed.
    ''' </summary>
    ''' <param name="paddr"></param>
    ''' <returns></returns>
    '''[Obsolete("Only needed and working for .NET 2.0 before Servicepack 1", false)]
    Private Shared Function GetEncodedMailAddress(ByVal paddr As MailAddress) As String
        '' DO NOT invoke member fullAddress of MailAddress, because
        '' ToEncodedString will construct the fullAddress in case it is null
        Return CType(GetType(MailAddress).InvokeMember("ToEncodedString", _
         BindingFlags.DeclaredOnly Or _
         BindingFlags.Public Or BindingFlags.NonPublic Or _
         BindingFlags.Instance Or BindingFlags.InvokeMethod, Nothing, paddr, Nothing), String)

    End Function


    ''' <summary>
    ''' Converts a stream to a string using systems's current ANSI codepage.
    ''' </summary>
    ''' <param name="pstream">System.IO.Stream stream</param>
    ''' <returns>string representation of the stream.</returns>
    Public Shared Function Stream2String(ByVal pstream As System.IO.Stream) As String
        Return Stream2String(pstream, Encoding.Default)
    End Function

    ''' <summary>
    ''' Converts a stream to a string.
    ''' </summary>
    ''' <param name="pstream"></param>
    ''' <param name="pencoding"></param>
    ''' <returns></returns>
    Public Shared Function Stream2String(ByVal pstream As System.IO.Stream, ByVal pencoding As Encoding) As String
        Dim lstreamPos As Long = pstream.Position
        pstream.Seek(0, SeekOrigin.Begin)
        Dim lbytes() As Byte
        ReDim lbytes(CInt(pstream.Length - 1))
        pstream.Read(lbytes, 0, CType(pstream.Length, Integer))
        pstream.Seek(lstreamPos, SeekOrigin.Begin)
        Return pencoding.GetString(lbytes)
    End Function


End Class

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------

I've creathed a method for sending e-mails using that class :

Public Sub EnviarviaSMTP(ByVal pServidorSMTP As String, ByVal pUsuario As String, ByVal pContrasena As String, _
  ByVal pAsunto As String, ByVal pMensaje As String, ByVal pOriginatarioEmail As String, _
  ByRef pDestinatarios() As String, Optional ByVal pDestinatariosCC() As String = Nothing, _
  Optional ByRef pAdjuntos() As String = Nothing, _
  Optional ByVal pTiempoEsperaEnvioMensaje As Integer = 5 * 60 * 1000, _
  Optional ByVal pMensajeHTML As String = "") 'tiempoespera en milisegundos
        Dim lMensajeAEnviar As System.Net.Mail.MailMessage = New System.Net.Mail.MailMessage() 'para enviar el mensaje
        Dim lSubjectEncoding As Encoding = Encoding.GetEncoding("iso8859-1")
        Dim lClienteSMTP As System.Net.Mail.SmtpClient
        Dim lMailAddress As System.Net.Mail.MailAddress



        lMensajeAEnviar.From = New System.Net.Mail.MailAddress(pOriginatarioEmail)
        'lMensajeAEnviar.To.Insert0, New System.Net.Mail.MailAddress(emaildestinatario))
        For Each ldest As String In pDestinatarios
            lMailAddress = New System.Net.Mail.MailAddress(ldest)
            clsBugFixerSystemNetMail.CorrectMailAddressEncodedWordRFC2047compliant(lMailAddress, System.Text.Encoding.GetEncoding("iso-8859-1"))
            lMensajeAEnviar.To.Add(lMailAddress)
        Next ldest
        If Not (pDestinatariosCC Is Nothing) Then
            For Each ldestCC As String In pDestinatariosCC
                lMailAddress = New System.Net.Mail.MailAddress(ldestCC)
                clsBugFixerSystemNetMail.CorrectMailAddressEncodedWordRFC2047compliant(lMailAddress, System.Text.Encoding.GetEncoding("iso-8859-1"))
                lMensajeAEnviar.CC.Add(lMailAddress)
            Next ldestCC
        End If
        lMailAddress = New System.Net.Mail.MailAddress(pOriginatarioEmail)
        clsBugFixerSystemNetMail.CorrectMailAddressEncodedWordRFC2047compliant(lMailAddress, System.Text.Encoding.GetEncoding("iso-8859-1"))
        lMensajeAEnviar.Sender = lMailAddress
        'lMensajeAEnviar.Headers.Item("Content Type") = pContentTypeMensaje
        lMensajeAEnviar.Body = pMensaje
        lMensajeAEnviar.BodyEncoding = Encoding.GetEncoding("iso8859-1")
        'lMensajeAEnviar.ContentTransferEncoding = lmsgleido.ContentTransferEncoding
        lMensajeAEnviar.SubjectEncoding = lSubjectEncoding
        lMensajeAEnviar.Subject = pAsunto 'QPEncoder(pAsunto, lSubjectEncoding)
        clsBugFixerSystemNetMail.CorrectSubjectEncodedWordRFC2047compliant(lMensajeAEnviar)
        If Not (pAdjuntos Is Nothing) Then
            For Each lAdjunto As String In pAdjuntos
                Dim mimeattach As System.Net.Mail.Attachment

                mimeattach = New System.Net.Mail.Attachment(lAdjunto)
                mimeattach.TransferEncoding = Net.Mime.TransferEncoding.Base64
                mimeattach.Name = System.IO.Path.GetFileName(lAdjunto) ' QPEncoder(System.IO.Path.GetFileName(lAdjunto), System.Text.Encoding.Default)
                lMensajeAEnviar.Attachments.Add(mimeattach)
            Next lAdjunto
        End If
        If pMensajeHTML <> "" Then
            'http://blogs.interakting.co.uk/brad/archive/2007/06/12/67.aspx para enviar
            'mensajes html con system.net.mail.mailmessage (lmensajeaenviar.AlternateViews.Add  )
            Dim lHTMLMens As System.Net.Mail.AlternateView
            lHTMLMens = System.Net.Mail.AlternateView.CreateAlternateViewFromString(pMensajeHTML, _
                                                                                    Nothing, System.Net.Mime.MediaTypeNames.Text.Html)
            lMensajeAEnviar.AlternateViews.Add(lHTMLMens)
        End If
        ErrorEnvioEmail = False
        Try
            lClienteSMTP = New System.Net.Mail.SmtpClient(pServidorSMTP, 25)
            lClienteSMTP.Credentials = New System.Net.NetworkCredential(pUsuario, pContrasena)
            lClienteSMTP.UseDefaultCredentials = False
            lClienteSMTP.EnableSsl = False
            lClienteSMTP.DeliveryMethod = Net.Mail.SmtpDeliveryMethod.Network
            lClienteSMTP.Timeout = pTiempoEsperaEnvioMensaje
            clsBugFixerSystemNetMail.ToggleMailHeaderInfoTypeForSubject(lMensajeAEnviar, True) 'HA DE LLAMARSE ANTES DEL SEND - usamos "arreglo" para que haga bien la codificación quoted-printable en subject
            lClienteSMTP.Send(lMensajeAEnviar)
            clsBugFixerSystemNetMail.ToggleMailHeaderInfoTypeForSubject(lMensajeAEnviar, False) 'HA DE LLAMARSE DESPUES DEL SEND
            lClienteSMTP = Nothing
        Catch ex As System.Net.Mail.SmtpException
            ErrorStrEnvioEmail = "En Función EnviarviaSMTP : Error " & ex.ToString()
            ErrorEnvioEmail = True
        End Try

    End Sub

--------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------


Sorry but comments and variables are in spanish.

Parameters used in the function are:
pServidorSMTP : ip address of dns name of SMTP server to use
pUsuario : User for authenticating to that server
pContrasena : Password for the authentication
pAsunto : Subject of message
pMensaje : Body of message encoded in iso-8859-1 ("like a simple text message")
pOriginatarioEmail : Sender of e-mail
pDestinatarios : Array of e-mail destinations
pDestinatariosCC : optional parameter of CC e-mail destinations
pAdjuntos : optional array parameter of paths to attached files to e-mail
pTiempoEsperaEnvioMensaje : optional parameter of time that waits for sending e-mail in miliseconds. If that number of miliseconds past and message is not send an error occurs.
pMensajeHTML : Body of the message in HTML format. It's sended as an alternative view to Body message. If e-mail client support HTML then HTML is shown.


Sorry for bad english.

Answer 8

VB6 upgrader to VB.nET:

Would have been nice to mention that you have converted this code from MailMergeLib (written in C#) which is published on http://www.codeproject.com/KB/IP/MailMergeLib.aspx, wouldn't it?

Answer 9

I'm so sorry for forgetting mentioning it.
I decided to write the source code reference links but I forgot.
The version of the c# code used for converting to vb.net is of 30/8/2008.

I have recently converted and added to the class the new CorrectLinesStartingWithDot function from the version of 23/12/2008.
Here it is, but is not using IsSwitchedOn:

''' <summary>
    ''' When talking to an SMTP server, SmtpClient should double all dots at the beginning of a line
    ''' for all text-based content. This works fine if MailMessage.Body is used. But it does not work
    ''' if AlternateViews or text attachments are used. The result is, that these dots get lost or - 
    ''' even worse - all content after the dot gets lost if it is followed by CRLF (RFC 2821 violation).
    ''' </summary>
    ''' <remarks>
    ''' This bug fix is not needed if MailMessage.Body is used. In this case .NET does
    ''' dot handling right. MailMergeMessage does not use it in order to have more control
    ''' over TransferEncoding and others.
    ''' This bug fix must be applied BEFORE CorrectQuotedPrintableRFC2045compliant.
    ''' </remarks>
    ''' <param name="att">All Attachments, AlternateViews und LinkedResources are based on AttachmentBase.</param>
    ''' <param name="encoding">System.Text.Encoding</param>
    Public Shared Sub CorrectLinesStartingWithDot(ByVal att As AttachmentBase, ByVal encoding As Encoding)

        ''no usado, isswitchedon
        ''If (Not IsSwitchedOn) Then
        '' Return
        ''End If

        If (System.Environment.Version.Major < 2 Or System.Environment.Version.Major > 4) Then
            Return
        End If

        If (att Is Nothing) Then
            Return
        End If

        If (encoding Is Nothing) Then

            encoding = encoding.UTF8
        End If

        Const flags As BindingFlags = BindingFlags.Instance Or BindingFlags.NonPublic Or BindingFlags.Public

        '' Do nothing if it's not an attachment is not a "text" type.
        If (att.TransferEncoding <> TransferEncoding.QuotedPrintable) And (att.TransferEncoding <> TransferEncoding.SevenBit) Then
            Return
        End If

        '' Get the System.Net.Mime.MimePart:
        Dim mimePart As Object = GetType(System.Net.Mail.AttachmentBase).GetField("part", flags).GetValue(att)

        '' Convert the content stream into a strng
        Dim mimeContent As String = Stream2String(att.ContentStream, encoding)

        '' if the line starts with a dot, double the dot
        If (mimeContent.StartsWith(".")) Then
            mimeContent = "." + mimeContent
        End If

        mimeContent = mimeContent.Replace(Environment.NewLine + ".", Environment.NewLine + "..")

        '' Convert the content stream to a well formated MemoryStream
        Dim correctedStream As System.IO.MemoryStream = New System.IO.MemoryStream(encoding.GetBytes(mimeContent))

        '' Set System.Net.Mime.MimePart.stream:
        mimePart.GetType().GetField("stream", flags).SetValue(mimePart, correctedStream)
    End Sub

Answer 10

Hi there,

 

i'm using sytem.net.mail in our framework at work. We are experiencing problem with spaces in the attachement filename. For some reason a space is removed from

the file attahcment name once its sent to stmp server. Its stange because the space always removed at a difference place , each time. We first tought that it was a problem with the smtp GateWay. However the server guy told us that the data that they receive from us is already corrupted once they receive it. So i have few questions:

1. Is that a know problem?

2. Is there a fix for that without using any other API than system.net.mail( i checked your article on codeproject  but can't find one)

3. Do you think that i could be rfc2047 encoding proglem(if yes how do fix it? Is it possible to do the encoding implicitly)

4.  Is your MailMergLib library could fix that problem?

I know , its a lot of question!

Thanks!

Answer 11

Never mind,

i just fixed my problem using your MailMergLib.bugfix class. THanks!