Download POP3 Emails

I know that all can send mails because it's easy, lol ! but when thinking about how to receive them!
So see and try !
Well we'll use here the TCPClient Class in the System.net.socket
The following class code creates Pop3 objects to simplify accessing emails from a standard POP3 server.But keep in mind that some servers require SSL or other authentication.
First create the class "POP3" and put this code on it :

Public Class Pop3
' ----- The default TCP/IP port number for POP3 is 110.
Public Port As Integer = 110
Public Messages As Integer = 0

Private Const CommandFailure As String = "-ERR"

Private Pop3Server As TcpClient
Private CommandSender As NetworkStream
Private ContentReceiver As StreamReader

Public Sub Connect(ByVal serverName As String, _
ByVal userName As String, ByVal password As String)
' ----- Initiate the connection to a POP3 server.
Dim commandData As String
Dim contentBuffer() As Byte
Dim responseString As String
Dim parts() As String

' ----- Connect to the POP3 server.
Try
Pop3Server = New TcpClient(serverName, Port)
CommandSender = Pop3Server.GetStream()
ContentReceiver = New StreamReader(CommandSender)
Catch
Throw
End Try

If (userName <> "") Then
' ----- Authenticate with the user ID.
commandData = "USER " & userName & vbCrLf
contentBuffer = _
System.Text.Encoding.ASCII.GetBytes( _
commandData.ToCharArray())
CommandSender.Write(contentBuffer, 0, _
contentBuffer.Length)
responseString = ContentReceiver.ReadLine()
If (Left(responseString, Len(CommandFailure)) = _
CommandFailure) Then
Throw New Exception("Invalid user name.")
End If

' ----- Send the authenticating password.
commandData = "PASS " & password & vbCrLf
contentBuffer = _
System.Text.Encoding.ASCII.GetBytes( _
commandData.ToCharArray())
CommandSender.Write(contentBuffer, 0, _
contentBuffer.Length)
responseString = ContentReceiver.ReadLine()
If (Left(responseString, Len(CommandFailure)) = _
CommandFailure) Then
Throw New Exception("Invalid password.")
End If
End If

' ----- Logged in. On some servers, the PASS command
' is not enough to push the server into a
' transaction state. Send a STAT command twice.
commandData = "STAT" + vbCrLf
contentBuffer = System.Text.Encoding.ASCII.GetBytes( _
commandData.ToCharArray())
CommandSender.Write(contentBuffer, 0, _
contentBuffer.Length)
responseString = ContentReceiver.ReadLine()

' ----- Get a count of the messages.
commandData = "STAT" + vbCrLf
contentBuffer = System.Text.Encoding.ASCII.GetBytes( _
commandData.ToCharArray())
CommandSender.Write(contentBuffer, 0, _
contentBuffer.Length)
responseString = ContentReceiver.ReadLine()
If (Left(responseString, Len(CommandFailure)) = _
CommandFailure) Then
Throw New Exception( _
"Could not retrieve message count.")
End If

' ----- The response includes two integers: a count
' and a size, separated by a space. Skip over
' the "+OK" part also.
parts = Split(responseString, " ")
Messages = Val(parts(1))
End Sub

Public Sub Disconnect()
' ----- Disconnect from the
POP3 server.
Dim commandData As String
Dim contentBuffer() As Byte
Dim responseString As String

' ----- Tell the server we're through.
commandData = "QUIT" & vbCrLf
contentBuffer = System.Text.Encoding.ASCII.GetBytes( _
commandData.ToCharArray())
CommandSender.Write(contentBuffer, 0, _
contentBuffer.Length)
responseString = ContentReceiver.ReadLine()

' ----- End the connection.
ContentReceiver.Close()
CommandSender.Close()

Pop3Server.Close()
End Sub

Function GetMessage(ByVal whichMessage As Integer) _
As String
' ----- Retrieve a single email message.
Dim commandData As String
Dim contentBuffer() As Byte
Dim responseString As String
Dim theMessage As New System.Text.StringBuilder
Dim oneLine As String

' ----- Check for an invalid message.
If (whichMessage <> Messages) Then
Throw New ArgumentOutOfRangeException(whichMessage, _
"Messages are numbered from 1 to the number " & _
"identified by the Messages property.")
End If

Try
' ----- Request the message.
commandData = "RETR " & whichMessage & vbCrLf
contentBuffer = _
System.Text.Encoding.ASCII.GetBytes( _
commandData.ToCharArray())
CommandSender.Write(contentBuffer, 0, _
contentBuffer.Length)
responseString = ContentReceiver.ReadLine()
If (Left(responseString, Len(CommandFailure)) = _
CommandFailure) Then
Throw New Exception("Message retrieval failed.")
End If

' ----- The message is all data until a line with
' a single dot (.) appears.
Do While (ContentReceiver.EndOfStream = False)
oneLine = ContentReceiver.ReadLine()
If (oneLine = ".") Then Exit Do
theMessage.AppendLine(oneLine)
Loop
Catch ex As InvalidOperationException
MsgBox("Message retrieval failed: " & ex.Message)
End Try

' ----- Return the constructed message.
Return theMessage.ToString()
End Function
End Class

Now let's Manage the form (make a new form) so add three TextBox controls named ServerName, UserName, and UserPassword. Set the UserPassword control's PasswordChar field to the asterisk character (*). Add a ListBox control named MessageList and two Button controls named ActGet and ActView. Set the Button controls' Text properties to Get Messages and View Message, respectively.


and then put this code

Private POP3Connection As Pop3 = Nothing

Private Sub ActGet_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles ActGet.Click
' ----- Initiate a POP3 connection.
Dim counter As Integer

' ----- First, disconnect any previous connection.
If (POP3Connection IsNot Nothing) Then
Try
POP3Connection.Disconnect()
Catch ex As Exception
' ----- Ignore.
End Try
End If
POP3Connection = Nothing

' ----- Clear any previous messages.
MessageList.Items.Clear()

' ----- Try the new connection.
Try

POP3Connection = New Pop3
POP3Connection.Connect(ServerName.Text, _
UserName.Text, UserPassword.Text)
Catch ex As Exception
MsgBox("Connection failure: " & ex.Message)
POP3Connection = Nothing
Return
End Try

' ----- How many messages?
If (POP3Connection.Messages = 0) Then
MsgBox("No messages found.")
POP3Connection.Disconnect()
POP3Connection = Nothing
Return
End If

' ----- Show each message.
For counter = 1 To POP3Connection.Messages
MessageList.Items.Add("Message Number " & counter)
Next counter
End Sub

Private Sub ActView_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles ActView.Click
' ----- Show a message.
Dim whichMessage As Integer
Dim parts As String()
Dim content As String

' ----- Which message? Each item has the format:
' Message Number x
If (MessageList.SelectedIndex = -1) Then Return
parts = Split(CStr(MessageList.SelectedItem), " ")
whichMessage = CInt(Val(parts(2)))

' ----- Get the content.
content = POP3Connection.GetMessage(whichMessage)

' ----- Show the content.
MsgBox(content)
End Sub

Private Sub MessageList_DoubleClick(ByVal sender As Object, _
ByVal e As System.EventArgs) _
Handles MessageList.DoubleClick
' ----- Same as the View button.
ActView.PerformClick()
End Sub

Private Sub Form1_FormClosing(ByVal sender As Object, _
ByVal e As System.Windows.Forms.FormClosingEventArgs) _
Handles Me.FormClosing
' ----- Disconnect before leaving.
On Error Resume Next

If (
POP3Connection IsNot Nothing) Then
POP3Connection.Disconnect()
POP3Connection = Nothing
End If
End Sub


Now try ! Works or not ?