Retrieve Email and Parse Email in C# - Tutorial

Retrieve Email and Parse Email in C# - Tutorial

This tutorial introduces how to retrieve email and parse email in C# using POP3/IMAP4/EWS/WebDAV protocol. It also demonstrates retrieving email over SSL/TLS connection, verifying email digital signature, decrypting encrypted email (S/MIME), parsing email attachment, parsing non-delivery report (NDR) and managing mail folder.

Sections:

• Retrieve email in a simple C# project
• Where can I get my POP3 server address, user and password?
• Troubleshooting

Retrieve email in a simple C# project

To better demonstrate how to retrieve email and parse email, let’s create a C# console project named “receiveemail” at first, and then add the reference of EAGetMail in your project.

Installation

EAGetMail is a POP3 and IMAP4 component which supports all operations of POP3/IMAP4/MIME/Exchange Web Service/WebDAV/SSL/S/MIME protocol. Before you can use the following example 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

Note

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\net[version]\EAGetMail{version}.dll from installation path, 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.

.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 1.1, 2.0, 3.5, 4.0, 4.5, 4.61, .NET Core 2.1 and .Net Compact Framework 2.0, 3.5.

[C# Example - Retrieve email from POP3 server]

Now add the following codes to the project. The following codes demonstrate how to retrieve email from a POP3 mail account. It downloads emails from POP3 server and deletes the email after the email is retrieved. In order to run it correctly, please change email server, user, password, folder, file name values.

using System;using System.Globalization;using System.IO;using EAGetMail; //add EAGetMail namespace

namespace receiveemail{

class Program

{

// Generate an unqiue email file name based on date time

static string _generateFileName(int sequence)

{

DateTime currentDateTime = DateTime.Now;

return string.Format("{0}-{1:000}-{2:000}.eml",

currentDateTime.ToString("yyyyMMddHHmmss", new CultureInfo("en-US")),

currentDateTime.Millisecond,

sequence);

}

static void Main(string[] args)

{

try

{

// Create a folder named "inbox" under current directory

// to save the email retrieved.

string localInbox = string.Format("{0}\\inbox", Directory.GetCurrentDirectory());

// If the folder is not existed, create it.

if (!Directory.Exists(localInbox))

{

Directory.CreateDirectory(localInbox);

}

MailServer oServer = new MailServer("pop3.emailarchitect.net",

"email",

"testpassword",

ServerProtocol.Pop3);

// Enable SSL/TLS connection, most modern email server require SSL/TLS by default

oServer.SSLConnection = true;

oServer.Port = 995;

// if your server doesn't support SSL/TLS, please use the following codes

// oServer.SSLConnection = false;

// oServer.Port = 110;

MailClient oClient = new MailClient("TryIt");

oClient.Connect(oServer);

MailInfo[] infos = oClient.GetMailInfos();

Console.WriteLine("Total {0} email(s)\r\n", infos.Length);

for (int i = 0; i < infos.Length; i++)

{

MailInfo info = infos[i];

Console.WriteLine("Index: {0}; Size: {1}; UIDL: {2}",

info.Index, info.Size, info.UIDL);

// Receive email from POP3 server

Mail oMail = oClient.GetMail(info);

Console.WriteLine("From: {0}", oMail.From.ToString());

Console.WriteLine("Subject: {0}\r\n", oMail.Subject);

// Generate an unqiue email file name based on date time.

string fileName = _generateFileName(i + 1);

string fullPath = string.Format("{0}\\{1}", localInbox, fileName);

// Save email to local disk

oMail.SaveAs(fullPath, true);

// Mark email as deleted from POP3 server.

oClient.Delete(info);

}

// Quit and expunge emails marked as deleted from POP3 server.

oClient.Quit();

Console.WriteLine("Completed!");

}

catch (Exception ep)

{

Console.WriteLine(ep.Message);

}

}

}}

If you set everything right, you can get emails in the mail folder. If the codes threw exception, then please have a look at the following section.

Where can I get my POP3 server address, user and password?

Because each email account provider has different server address, so you should query your POP3 server address from your email account provider. User name is your email address or your email address without domain part. It depends on your email provider setting.

When you execute above example code, if you get error about “Networking connection” or “No such host”, it is likely that your POP3 server address is not correct. If you get an error like “Invalid user or password”, it is likely that you did not set the correct user or password.

Finally, if you have already set your account in your email client such as Outlook or Window Mail, you can query your POP3 server address, user in your email client. For example, you can choose menu -> Tools -> Accounts -> Your email account -> Properties -> Servers in Outlook express or Windows Mail to get your POP3 server, user. Using EAGetMail to receive email does not require you have email client installed on your machine or MAPI, however you can query your exist email accounts in your email client.

Troubleshooting

When you retrieve email in above simple project, if it returned an error, please have a look at the following tips:

“No Such Host” Error

This error means DNS server cannot resolve POP3 server, you should check if you input correct server address. If your server address is correct, you should check if your DNS server setting is correct.

Common “Socket/Networking Connection” Error

This error means there is a problem with networking connection to POP3 server. You can use Windows built-in Telnet command to detect the networking connection.

Using Telnet to detect networking connection to POP3 server

Note

Notice: in Windows 2008/Windows 8 or later version, Telnet Client is not installed by default, you should enable this command in Control Panel -> Programs and Features -> Turn Windows feature on or off -> have Telnet Client checked.

Under DOS command prompt, input telnet [serveraddress] [port]

telnet mail.emailarchitect.net 110

If the networking connection to your POP3 server is good, it should return a message like +OK .... If it returns Could not open connection to ..., that means the networking connection to POP3 server is bad, or outbound 110 port is blocked by anti-virus software, firewall or ISP. Please have a look at the following screenshot:

POP3 110, 995 port, IMAP4 143, 993 port and SSL

• 110 port is the default POP3 server port to receive email. 995 port is the common POP3 SSL port used to receive email over implicit SSL connection.
• 143 port is the default IMAP4 server port, 993 port is the common port for IMAP4 SSL.

If you use telnet to test 995/993 port, it doesn’t return the +OK..., because it requires SSL hand shake. If the connection is ok, telnet returns a flash cursor.

Now SSL is commonly used, many email servers require SSL connection such as Gmail, Outlook, Office 365 and Yahoo. In this case you should set MailServer.SSLConnection to true and change MailServer.Port to 995 (POP3) or 993 (IMAP4).

“-ERR user authentication” Error

This error means user authentication is failed, you should check whether you input correct user/password. Password is always case-sensitive.

Other error returned by POP3 server

If POP3 server returns an error, it usually returns description about this error. You can use the following codes to generate a log file to learn all POP3 session between client and server.

[C# - Using log file to detect POP3 server response - Example]

oClient.LogFileName = "d:\\pop3.txt";

Next Section

In this section, I introduced retrieving email in C# with POP3 protocol. At next section I will introduce how to retrieve email from IMAP4 server.

Retrieve Email from IMAP4 server in C#

In previous section, I introduced retrieving email from POP3 server in C#. In this section, I will introduce the IMAP4 server.

Sections:

• Introduction
• [C# Example - Retrieve email from IMAP4 inbox]
• [C# Example - Retrieve email from “Deleted Items”]

Introduction

IMAP4 protocol is different with POP3 protocol. First of all, IMAP4 supports retrieving email from different mail folder and folder management. Secondly, IMAP4 supports mail flags management. Therefore, we can do more things with IMAP4 server. To better understand the IMAP4 protocol, please see the following examples.

Note

Remarks: All of examples in this section are based on first section: A simple C# project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference to your project.

[C# Example - Retrieve email from IMAP4 inbox]

The following example codes demonstrate how to download email from IMAP4 server default mailbox. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

To get the full sample projects, please refer to Samples section.

using System;using System.Globalization;using System.IO;using EAGetMail; //add EAGetMail namespace

namespace receiveemail{

class Program

{

// Generate an unqiue email file name based on date time

static string _generateFileName(int sequence)

{

DateTime currentDateTime = DateTime.Now;

return string.Format("{0}-{1:000}-{2:000}.eml",

currentDateTime.ToString("yyyyMMddHHmmss", new CultureInfo("en-US")),

currentDateTime.Millisecond,

sequence);

}

static void Main(string[] args)

{

try

{

// Create a folder named "inbox" under current directory

// to save the email retrieved.

string localInbox = string.Format("{0}\\inbox", Directory.GetCurrentDirectory());

// If the folder is not existed, create it.

if (!Directory.Exists(localInbox))

{

Directory.CreateDirectory(localInbox);

}

MailServer oServer = new MailServer("imap.emailarchitect.net",

"email",

"testpassword",

ServerProtocol.Imap4);

// Enable SSL/TLS connection, most modern email server require SSL/TLS by default

oServer.SSLConnection = true;

oServer.Port = 993;

// if your server doesn't support SSL/TLS, please use the following codes

// oServer.SSLConnection = false;

// oServer.Port = 143;

MailClient oClient = new MailClient("TryIt");

oClient.Connect(oServer);

MailInfo[] infos = oClient.GetMailInfos();

Console.WriteLine("Total {0} email(s)\r\n", infos.Length);

for (int i = 0; i < infos.Length; i++)

{

MailInfo info = infos[i];

Console.WriteLine("Index: {0}; Size: {1}; UIDL: {2}",

info.Index, info.Size, info.UIDL);

// Receive email from IMAP4 server

Mail oMail = oClient.GetMail(info);

Console.WriteLine("From: {0}", oMail.From.ToString());

Console.WriteLine("Subject: {0}\r\n", oMail.Subject);

// Generate an unqiue email file name based on date time.

string fileName = _generateFileName(i + 1);

string fullPath = string.Format("{0}\\{1}", localInbox, fileName);

// Save email to local disk

oMail.SaveAs(fullPath, true);

// Mark email as deleted from IMAP4 server.

oClient.Delete(info);

}

// Quit and expunge emails marked as deleted from IMAP4 server.

oClient.Quit();

Console.WriteLine("Completed!");

}

catch (Exception ep)

{

Console.WriteLine(ep.Message);

}

}

}}

Because IMAP4 protocol supports folder access, so we can retrieve email from other mailbox rather than default “INBOX”. POP3 protocol doesn’t support this feature.

[C# Example - Retrieve email from “Deleted Items”]

The following example codes demonstrate how to retrieve emails from “Deleted Items” in an IMAP4 account. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

To get the full sample projects, please refer to Samples section.

using System;using System.Globalization;using System.IO;using EAGetMail; //add EAGetMail namespace

namespace receiveemail{

class Program

{

// if you want to search sub folder, use parentfolder\subfolder as folderPath

// for example: inbox\mysubfolder

static Imap4Folder FindFolder(string folderPath, Imap4Folder[] folders)

{

int count = folders.Length;

for (int i = 0; i < count; i++)

{

Imap4Folder folder = folders[i];

if (string.Compare(folder.LocalPath, folderPath, true) == 0)

{

return folder;

}

folder = FindFolder(folderPath, folder.SubFolders);

if (folder != null)

{

return folder;

}

}

// No folder found

return null;

}

// Generate an unqiue email file name based on date time

static string _generateFileName(int sequence)

{

DateTime currentDateTime = DateTime.Now;

return string.Format("{0}-{1:000}-{2:000}.eml",

currentDateTime.ToString("yyyyMMddHHmmss", new CultureInfo("en-US")),

currentDateTime.Millisecond,

sequence);

}

static void Main(string[] args)

{

try

{

// Create a folder named "inbox" under current directory

// to save the email retrieved.

string localInbox = string.Format("{0}\\inbox", Directory.GetCurrentDirectory());

// If the folder is not existed, create it.

if (!Directory.Exists(localInbox))

{

Directory.CreateDirectory(localInbox);

}

MailServer oServer = new MailServer("imap.emailarchitect.net",

"email",

"testpassword",

ServerProtocol.Imap4);

// Enable SSL/TLS connection, most modern email server require SSL/TLS by default

oServer.SSLConnection = true;

oServer.Port = 993;

// if your server doesn't support SSL/TLS, please use the following codes

// oServer.SSLConnection = false;

// oServer.Port = 143;

MailClient oClient = new MailClient("TryIt");

oClient.Connect(oServer);

// find folder

Imap4Folder folder = FindFolder("Deleted Items", oClient.GetFolders());

if (folder == null)

{

throw new Exception("Folder not found!");

}

// select dest folder

oClient.SelectFolder(folder);

MailInfo[] infos = oClient.GetMailInfos();

Console.WriteLine("Total {0} email(s)\r\n", infos.Length);

for (int i = 0; i < infos.Length; i++)

{

MailInfo info = infos[i];

Console.WriteLine("Index: {0}; Size: {1}; UIDL: {2}",

info.Index, info.Size, info.UIDL);

// Receive email from IMAP4 server

Mail oMail = oClient.GetMail(info);

Console.WriteLine("From: {0}", oMail.From.ToString());

Console.WriteLine("Subject: {0}\r\n", oMail.Subject);

// Generate an unqiue email file name based on date time.

string fileName = _generateFileName(i + 1);

string fullPath = string.Format("{0}\\{1}", localInbox, fileName);

// Save email to local disk

oMail.SaveAs(fullPath, true);

// Mark email as deleted from IMAP4 server.

oClient.Delete(info);

}

// Quit and expunge emails marked as deleted from IMAP4 server.

oClient.Quit();

Console.WriteLine("Completed!");

}

catch (Exception ep)

{

Console.WriteLine(ep.Message);

}

}

}}

Next Section

At next section I will introduce how to retrieve email from Exchange Server with Web Service protocol.

Retrieve Email from Exchange Server with Web Service (EWS) in C#

In previous section, I introduced how to retrieve email from IMAP4 server. In this section, I will introduce the Exchange Web Service (EWS) protocol (Exchange 2007/2010 or later version).

Sections:

• Introduction
• [C# Example - Retrieve email from Exchange INBOX]
• [C# Example - Retrieve email from “Deleted Items”]

Introduction

Exchange Web Service (EWS) protocol is similar with IMAP4 protocol. First of all, it supports retrieving email from different mail folder and folder management. Secondly, Exchange Web Service supports mail read flag management. Therefore, we can do more things with Exchange server. To better understand the Exchange Web Service protocol, please see the following examples.

Exchange Server supports POP3/IMAP4 protocol as well, but in Exchange 2007 or later version, POP3/IMAP4 service is disabled by default. If you don’t want to use POP3/IMAP4 to download email from Exchange Server, you can use Exchange Web Service (Exchange 2007/2010/2013/2016 or later version) or WebDAV (Exchange 2000/2003) protocol.

Office 365 also supports EWS protocol.

Note

Remarks: All of examples in this section are based on first section: A simple C# project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference to your project.

[C# Example - Retrieve email from Exchange INBOX]

The following example codes demonstrate how to download email from Exchange 2007/2010/2013/2016 server default mailbox using EWS protocol. In order to run it correctly, please change email server, user, password, folder, file name values.

Note

To get the full sample projects, please refer to Samples section.

using System;using System.Globalization;using System.IO;using EAGetMail; //add EAGetMail namespace

namespace receiveemail{

class Program

{

// Generate an unqiue email file name based on date time

static string _generateFileName(int sequence)

{

DateTime currentDateTime = DateTime.Now;

return string.Format("{0}-{1:000}-{2:000}.eml",

currentDateTime.ToString("yyyyMMddHHmmss", new CultureInfo("en-US")),

currentDateTime.Millisecond,

sequence);

}

static void Main(string[] args)

{

try

{

// Create a folder named "inbox" under current directory

// to save the email retrieved.

string localInbox = string.Format("{0}\\inbox", Directory.GetCurrentDirectory());

// If the folder is not existed, create it.

if (!Directory.Exists(localInbox))