Using IMAP in VB.Net to retrieve Mails from MS Exchange Server - vb.net

Question

I am referring to a previous post somewhere in the past (cf. Hyperlink). I could not add any comments, nor did I consider writing a reply since my Problem differs slightly. Please excuse if I posted in the wrong section or for opening a new thread on this topic, I am still new to this Forum.
Please let me illustrate the following issue: Similar to this post, I would like to access and retrieve emails and attachments from a MS Exchange Server. I mainly used the code provided by in the Hyperlink above, but I could not connect to the mail Server (I used port 587). In my opinion there was a successful Connection, but the code stops when reaching the following line
Dim Read_Stream2 = New StreamReader(Sstream)
Saying that the data stream could not be read.
I also have a question about this particular line, since I am unable to figure out why there is need to convert the NetworkStream into an SslStream and then into a StreamReader Object. Could somebody please explain this necessity?
As for the remaining Problem, please consider my code so far below. If it might be too cumbersome using IMAP, I would also welcome hints about how to achieve this goal using POP3.
Thanks a mil in advance for any help provided.
Imports System.Net.Sockets
Imports System.IO
Imports System.Text
Imports System.Net.Security
Public Class emailDownloader
Dim ServerNm As String
Dim UsrNm As String
Dim PassStr As String
Dim _IntPort As Integer
Dim ImapClient As New Net.Sockets.TcpClient
Dim NetworkS_stream As NetworkStream
Dim m_sslStream As SslStream
Dim Read_Stream As StreamReader
Dim StatResp As String
Dim m_buffer() As Byte
Function Login(ByVal Sstream As SslStream, ByVal Server_Command As String)
ImapClient = New TcpClient(ServerNm, _IntPort)
NetworkS_stream = ImapClient.GetStream 'Read the stream
Sstream = New SslStream(NetworkS_stream)
Dim Read_Stream2 = New StreamReader(Sstream)
Server_Command = Server_Command ' + vbCrLf
m_buffer = System.Text.Encoding.ASCII.GetBytes(Server_Command.ToCharArray())
Sstream.Write(m_buffer, 0, m_buffer.Length)
Dim Server_Reponse As String
Server_Reponse = Read_Stream2.ReadLine()
Return Server_Reponse
End Function
Private Sub btnStart_Click(sender As System.Object, e As System.EventArgs) Handles btnStart.Click
lbMailsRetrieved.Items.Clear()
ServerNm = tbServerName.Text
_IntPort = tbPortName.Text
UsrNm = tbUserName.Text
PassStr = tbPasswort.Text
StatResp = Login(m_sslStream, "LOGIN " + UsrNm + " " + PassStr + " ") & vbCrLf
lbMailsRetrieved.Items.Add(StatResp)
End Sub
End Class
There was a solution initially programmed in C#, which can be found here. I modified the code a bit and it is working for exchange (and only that).
Imports Microsoft.Exchange.WebServices.Data
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Linq
Imports System.Net.Sockets
Imports System.Text
Imports System.Threading.Tasks
Imports System.Windows.Forms
Namespace ReadMailFromExchangeServer
Public Class Form1
Inherits Form
Private exchange As ExchangeService
Public Sub New()
InitializeComponent()
lstMsg.Clear()
lstMsg.View = View.Details
lstMsg.Columns.Add("Date", 150)
lstMsg.Columns.Add("From", 250)
lstMsg.Columns.Add("Subject", 400)
lstMsg.Columns.Add("Has Attachment", 50)
lstMsg.Columns.Add("Id", 100)
lstMsg.FullRowSelect = True
End Sub
Private Sub btnRead_Click(sender As Object, e As EventArgs) Handles btnRead.Click
ConnectToExchangeServer()
'Dim ts As New TimeSpan(0, -1, 0, 0)
'Dim [date] As DateTime = DateTime.Now.Add(ts)
'Dim filter As New SearchFilter.IsGreaterThanOrEqualTo(ItemSchema.DateTimeReceived, [date])
If exchange IsNot Nothing Then
Dim findResults As FindItemsResults(Of Item) = exchange.FindItems(WellKnownFolderName.Inbox, New ItemView(50))
'Original
'Dim findResults As FindItemsResults(Of Item) = exchange.FindItems(WellKnownFolderName.Inbox, filter, New ItemView(50))
For Each item As Item In findResults
Dim message As EmailMessage = EmailMessage.Bind(exchange, item.Id)
Dim listItem As New ListViewItem({message.DateTimeReceived.ToString(), _
message.From.Name.ToString() + _
"(" + message.From.Address.ToString() + ")", _
message.Subject, (If((message.HasAttachments), "Yes", "No")), _
message.Id.ToString()})
lstMsg.Items.Add(listItem)
Next
If findResults.Items.Count <= 0 Then
lstMsg.Items.Add("No Messages found!!")
End If
End If
End Sub
Public Sub ConnectToExchangeServer()
lblMsg.Text = "Connecting to Exchange Server.."
lblMsg.Refresh()
Try
exchange = New ExchangeService(ExchangeVersion.Exchange2007_SP1)
exchange.Credentials = New WebCredentials("abc", "xyz")
exchange.AutodiscoverUrl("efg")
lblMsg.Text = "Connected to Exchange Server : " + exchange.Url.Host
lblMsg.Refresh()
Catch ex As Exception
lblMsg.Text = "Error Connecting to Exchange Server!!" + ex.Message
lblMsg.Refresh()
End Try
End Sub
Private Sub btnLoadAttachment_Click(sender As Object, e As EventArgs) Handles btnLoadAttachment.Click
If exchange IsNot Nothing Then
If lstMsg.Items.Count > 0 Then
Dim item As ListViewItem = lstMsg.SelectedItems(0)
If item IsNot Nothing Then
Dim msgid As String = item.SubItems(4).Text.ToString()
Dim message As EmailMessage = EmailMessage.Bind(exchange, New ItemId(msgid))
If message.HasAttachments AndAlso TypeOf message.Attachments(0) Is FileAttachment Then
Dim fileAttachment As FileAttachment = TryCast(message.Attachments(0), FileAttachment)
'Change the below Path   
fileAttachment.Load("C:[my_path]" + fileAttachment.Name)
lblAttach.Text = "Attachment Downloaded : " + fileAttachment.Name
Else
MessageBox.Show("No Attachments found!!")
End If
Else
MessageBox.Show("Please select a Message!!")
End If
Else
MessageBox.Show("Messages not loaded!!")
End If
Else
MessageBox.Show("Not Connected to Mail Server!!")
End If
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs)
End Sub
Private Sub InitializeComponent()
Me.btnRead = New System.Windows.Forms.Button()
Me.lstMsg = New System.Windows.Forms.ListView()
Me.btnLoadAttachment = New System.Windows.Forms.Button()
Me.lblMsg = New System.Windows.Forms.Label()
Me.label1 = New System.Windows.Forms.Label()
Me.lblAttach = New System.Windows.Forms.Label()
Me.SuspendLayout()
'
'btnRead
'
Me.btnRead.BackgroundImageLayout = System.Windows.Forms.ImageLayout.None
Me.btnRead.FlatStyle = System.Windows.Forms.FlatStyle.Flat
Me.btnRead.Location = New System.Drawing.Point(39, 284)
Me.btnRead.Name = "btnRead"
Me.btnRead.Size = New System.Drawing.Size(174, 23)
Me.btnRead.TabIndex = 0
Me.btnRead.Text = "Read Mails"
Me.btnRead.UseVisualStyleBackColor = True
'
'lstMsg
'
Me.lstMsg.Location = New System.Drawing.Point(27, 70)
Me.lstMsg.Name = "lstMsg"
Me.lstMsg.Size = New System.Drawing.Size(664, 191)
Me.lstMsg.TabIndex = 1
Me.lstMsg.UseCompatibleStateImageBehavior = False
'
'btnLoadAttachment
'
Me.btnLoadAttachment.FlatStyle = System.Windows.Forms.FlatStyle.System
Me.btnLoadAttachment.Location = New System.Drawing.Point(517, 284)
Me.btnLoadAttachment.Name = "btnLoadAttachment"
Me.btnLoadAttachment.Size = New System.Drawing.Size(174, 23)
Me.btnLoadAttachment.TabIndex = 2
Me.btnLoadAttachment.Text = "Load Attachments"
Me.btnLoadAttachment.UseVisualStyleBackColor = True
'
'lblMsg
'
Me.lblMsg.AutoSize = True
Me.lblMsg.Location = New System.Drawing.Point(36, 361)
Me.lblMsg.Name = "lblMsg"
Me.lblMsg.Size = New System.Drawing.Size(38, 13)
Me.lblMsg.TabIndex = 3
Me.lblMsg.Text = "Ready"
'
'label1
'
Me.label1.AutoSize = True
Me.label1.Location = New System.Drawing.Point(24, 54)
Me.label1.Name = "label1"
Me.label1.Size = New System.Drawing.Size(82, 13)
Me.label1.TabIndex = 4
Me.label1.Text = "Today's Messages"
'
'lblAttach
'
Me.lblAttach.AutoSize = True
Me.lblAttach.Location = New System.Drawing.Point(514, 361)
Me.lblAttach.Name = "lblAttach"
Me.lblAttach.Size = New System.Drawing.Size(148, 13)
Me.lblAttach.TabIndex = 5
Me.lblAttach.Text = "No attachmment downloaded"
'
'Form1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.ClientSize = New System.Drawing.Size(812, 591)
Me.Controls.Add(Me.lblAttach)
Me.Controls.Add(Me.label1)
Me.Controls.Add(Me.lblMsg)
Me.Controls.Add(Me.btnLoadAttachment)
Me.Controls.Add(Me.lstMsg)
Me.Controls.Add(Me.btnRead)
Me.Name = "Form1"
Me.Text = "Form1"
Me.ResumeLayout(False)
Me.PerformLayout()
End Sub
Friend WithEvents btnRead As System.Windows.Forms.Button
Friend WithEvents lstMsg As System.Windows.Forms.ListView
Friend WithEvents btnLoadAttachment As System.Windows.Forms.Button
Friend WithEvents lblMsg As System.Windows.Forms.Label
Friend WithEvents label1 As System.Windows.Forms.Label
Friend WithEvents lblAttach As System.Windows.Forms.Label
End Class
End Namespace

Answer 1

For the issue described in the beginning, the present code provides a solution. Thus I would like to mark this is an answer and close this thread (I know, usually one should not mark their very own answer as answer). Hope this approach is ok.