C# .NET - How to read mail from POP3 inbox using c#

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Net.NetworkInformation;
using System.Net.Security;
using System.Net.Sockets;
protected void Button9_Click(object sender, EventArgs e) 
{
try
{
TcpClient tcpclient = new TcpClient(); // create an instance of TcpClient
tcpclient.Connect("pop.gmail.com", 995); // HOST NAME POP SERVER and gmail uses port number 995 for POP 
System.Net.Security.SslStream sslstream = new SslStream(tcpclient.GetStream()); // This is Secure Stream // opened the connection between client and POP Server
sslstream.AuthenticateAsClient("pop.gmail.com"); // authenticate as client 
//bool flag = sslstream.IsAuthenticated; // check flag 
System.IO.StreamWriter sw = new StreamWriter(sslstream); // Asssigned the writer to stream
System.IO.StreamReader reader = new StreamReader(sslstream); // Assigned reader to stream
sw.WriteLine("USER your_gmail_user_name@gmail.com"); // refer POP rfc command, there very few around 6-9 command
sw.Flush(); // sent to server
sw.WriteLine("PASS your_gmail_password"); 
sw.Flush();
sw.WriteLine("RETR 1"); // this will retrive your first email 
sw.Flush();
sw.WriteLine("Quit "); // close the connection
sw.Flush();
string str = string.Empty; 
string strTemp = string.Empty;
while ((strTemp = reader.ReadLine()) != null) 
{
if (strTemp == ".") // find the . character in line
{
break; 
}
if (strTemp.IndexOf("-ERR") != -1) 
{
break; 
}
str += strTemp;
}
Response.Write(str);
Response.Write("<BR>" + "Congratulation.. ....!!! You read your first gmail email "); 
}
catch (Exception ex) 
{
Response.Write(ex.Message);
}
}

 public TcpClient Server;
 public NetworkStream NetStrm;
 public StreamReader  RdStrm;
 public string Data;
 public byte[] szData;
 public string CRLF = "\r\n";

Here's the code for when the Connect Button is clicked:

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private void ConnectBtn_Click(object sender, System.EventArgs e)
{
    // change cursor into wait cursor
    Cursor cr = Cursor.Current;
    Cursor.Current = Cursors.WaitCursor;
    // create server POP3 with port 110
    Server = new TcpClient(POPServ.Text,110);
    Status.Items.Clear();
    try
    {
        // initialization
        NetStrm = Server.GetStream();
        RdStrm= new StreamReader(Server.GetStream());
        Status.Items.Add(RdStrm.ReadLine());
        // Login Process
        Data = "USER "+ User.Text+CRLF;
        szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
        NetStrm.Write(szData,0,szData.Length);
        Status.Items.Add(RdStrm.ReadLine());
        Data = "PASS "+ Passw.Text+CRLF;
        szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
        NetStrm.Write(szData,0,szData.Length);
        Status.Items.Add(RdStrm.ReadLine());
        // Send STAT command to get information ie: number of mail and size
        Data = "STAT"+CRLF;
        szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
        NetStrm.Write(szData,0,szData.Length);
        Status.Items.Add(RdStrm.ReadLine());
        // change enabled - disabled button
        ConnectBtn.Enabled = false;
        DisconnectBtn.Enabled = true;
        RetrieveBtn.Enabled = true;
        // back to normal cursor
        Cursor.Current = cr;
    }
    catch(InvalidOperationException err)
    {
        Status.Items.Add("Error: "+err.ToString());
    }
}    

Here's the code for when the Disconnect Button is clicked:

private void DisconnectBtn_Click(object sender, System.EventArgs e)
{
    // change cursor into wait cursor
    Cursor cr = Cursor.Current;
    Cursor.Current = Cursors.WaitCursor;
    // Send QUIT command to close session from POP server
    Data = "QUIT"+CRLF;
    szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
    NetStrm.Write(szData,0,szData.Length);
    Status.Items.Add(RdStrm.ReadLine());
    //close connection
    NetStrm.Close();
    RdStrm.Close();
    // change enabled - disabled button
    ConnectBtn.Enabled = true;
    DisconnectBtn.Enabled = false;
    RetrieveBtn.Enabled = false;
    // back to normal cursor
    Cursor.Current = cr;
}

Here's code when Retrieve Button clicked:

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private void RetrieveBtn_Click(object sender, System.EventArgs e)
{
    // change cursor into wait cursor
    Cursor cr = Cursor.Current;
    Cursor.Current = Cursors.WaitCursor;
    string szTemp;
    Message.Clear();
    try
    {
        // retrieve mail with number mail parameter
        Data = "RETR "+ Number.Text+CRLF;
        szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
        NetStrm.Write(szData,0,szData.Length);
        szTemp = RdStrm.ReadLine();
        if(szTemp[0]!='-') 
        {
            while(szTemp!=".")
            {
                Message.Text += szTemp;
                szTemp = RdStrm.ReadLine();
            }
        }
        else
        {
            Status.Items.Add(szTemp);
        }
        // back to normal cursor
        Cursor.Current = cr;
    }
    catch(InvalidOperationException err)
    {
        Status.Items.Add("Error: "+err.ToString());
    }
}

Hi,

I used following code to retrieve mail from POP3 server. You will need two function connect to server and retrieve the mails. You will need to have the permission to read the server contents.

private void ConnectBtn_Click(object sender, System.EventArgs e)
{
    // change cursor into wait cursor
    Cursor cr = Cursor.Current;
    Cursor.Current = Cursors.WaitCursor;

    // create server POP3 with port 110
    Server = new TcpClient(POPServ.Text,110);
    Status.Items.Clear();

    try
    {
        // initialization
        NetStrm = Server.GetStream();
        RdStrm= new StreamReader(Server.GetStream());
        Status.Items.Add(RdStrm.ReadLine());

        // Login Process
        Data = "USER "+ User.Text+CRLF;
        szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
        NetStrm.Write(szData,0,szData.Length);
        Status.Items.Add(RdStrm.ReadLine());

        Data = "PASS "+ Passw.Text+CRLF; szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray()); NetStrm.Write(szData,0,szData.Length);
        Status.Items.Add(RdStrm.ReadLine());

        // Send STAT command to get information ie: number of mail and size
        Data = "STAT"+CRLF;
        szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
        NetStrm.Write(szData,0,szData.Length);
        Status.Items.Add(RdStrm.ReadLine());

        // change enabled - disabled button
        ConnectBtn.Enabled = false;
        DisconnectBtn.Enabled = true;
        RetrieveBtn.Enabled = true;

        // back to normal cursor
        Cursor.Current = cr;

    }
    catch(InvalidOperationException err)
    {
        Status.Items.Add("Error: "+err.ToString());
    }
}   

private void RetrieveBtn_Click(object sender, System.EventArgs e)
{
    // change cursor into wait cursor
    Cursor cr = Cursor.Current;
    Cursor.Current = Cursors.WaitCursor;
    string szTemp;
    Message.Clear();
    try
    {
        // retrieve mail with number mail parameter
        Data = "RETR "+ Number.Text+CRLF;
        szData = System.Text.Encoding.ASCII.GetBytes(Data.ToCharArray());
        NetStrm.Write(szData,0,szData.Length);
        szTemp = RdStrm.ReadLine();
        if(szTemp[0]!='-') 
        {
            while(szTemp!=".")
            {
                Message.Text += szTemp;
                szTemp = RdStrm.ReadLine();
            }
        }
        else
        {
            Status.Items.Add(szTemp);
        }
        // back to normal cursor
        Cursor.Current = cr;
    }
    catch(InvalidOperationException err)
    {
        Status.Items.Add("Error: "+err.ToString());
    }
}

http://www.codeproject.com/KB/IP/popapp.aspx

-PAresh