In most cases the first thing you need from an IMAP server is to access INBOX folder. Mail.dll has a special method for that, as this is the only folder that must exist on every IMAP server. It’s Imap.SelectInbox.

Most servers, of course, allow client to access more folders. You can list all IMAP folders using Imap.GetFolders method.

If you want to access different IMAP folder than Inbox, you need to use overloaded Imap.Select method which takes string parameter (folder name) or FolderInfo parameter (returned from a call to Imap.GetFolders method).

After that you can use GetAll, Search and GetMessageByUID methods to search and download email messages.

// C#

using (Imap imap = new Imap())
{
    imap.Connect("imap.example.com");    // or ConnectSSL for SSL
    imap.Login("user", "password");

    imap.Select("Sent items");

    Console.WriteLine(
        "There are {0} messages in 'Sent items'",
        imap.GetAll().Count);

    imap.Close();
}

' VB.NET

Using imap As New Imap()
	imap.Connect("imap.example.com")	' or ConnectSSL for SSL
	imap.Login("user", "password")

	imap.[Select]("Sent items")

	Console.WriteLine( _
		"There are {0} messages in 'Sent items'", _
		imap.GetAll().Count)

	imap.Close()
End Using

There is no established standard on naming common IMAP folders like ‘Sent mail’, ‘Spam’ etc. However some servers support XLIST command (Gmail) or SpecialUse extension that allow to identify common folders on this particular IMAP server.

This makes quite difficult for an IMAP client to know the real purpose of the folders on the server.

Fortunately there are two IMAP protocol extensions:

• XLIST – supported by Gmail
• SPECIAL-USE – RFC standardized extension

You can check if your servers support it by checking if SupportedExtensions returns ImapExtension.XList or ImapExtension.SpecialUse

Both extensions are supported by Mail.dll and, if your server supports any of them, you can take advantage of CommonFolders class. CommonFolders allows you to get the name of the folder and Select it, by knowing its purpose (for example Spam folder may be called “Junk email” on the server).

// C# version:

using (Imap imap = new Imap())
{
    imap.ConnectSSL("imap.gmail.com");
    imap.Login("pat@gmail.com", "password");

    CommonFolders folders = new CommonFolders(imap.GetFolders());

    Console.WriteLine("Inbox folder: " + folders.Inbox.Name);
    Console.WriteLine("Sent folder: " + folders.Sent.Name);
    Console.WriteLine("Spam folder: " + folders.Spam.Name);

    // You can select folders easy:
    imap.Select(folders.Inbox);
    imap.Select(folders.Sent);
    imap.Select(folders.Spam);

    imap.Close();
}

' VB.NET version:

Using imap As New Imap()
    imap.ConnectSSL("imap.gmail.com")
    imap.Login("pat@gmail", "password")

    Dim folders As New CommonFolders(imap.GetFolders())

    Console.WriteLine("Inbox folder: " + folders.Inbox.Name)
    Console.WriteLine("Sent folder: " + folders.Sent.Name)

    ' You can select folders easy:
    imap.Select(folders.Inbox)
    imap.Select(folders.Sent)

    imap.Close()
End Using

You can check if you can use CommonFolders with following code:

// C#

List<ImapExtension> extensions = client.SupportedExtensions();
bool canUseCommonFolders = extensions.Contains(ImapExtension.XList)
    || extensions.Contains(ImapExtension.SpecialUse);

' VB.NET

Dim extensions As List(Of ImapExtension) = client.SupportedExtensions()
Dim canUseCommonFolders As Boolean = extensions.Contains(ImapExtension.XList) OrElse extensions.Contains(ImapExtension.SpecialUse)

There are two ways of labeling message with Gmail system label (e.g. Starred)

Imap.GmailLabelMessageByUID method

GmailLabelMessageByUID method uses Gmail’s X-GM-LABELS extension to the IMAP protocol. You need to provide a folder flag name for it to work correctly e.g. @”\Starred”.

You can use FolderFlag class static properties to get common flags:
FolderFlag.XImportant, FolderFlag.XSpam, FolderFlag.XStarred.

// C#

using (Imap imap = new Imap())
{
    imap.ConnectSSL("imap.gmail.com");
    imap.Login("pat@gmail.com", "password");

    imap.SelectInbox();
    long last = imap.GetAll().Last();

    imap.GmailLabelMessageByUID(last, FolderFlag.XStarred.Name);

    imap.Close();
}

' VB.NET

Using imap As New Imap()
    imap.ConnectSSL("imap.gmail.com")
    imap.Login("pat@gmail.com", "password")

    imap.SelectInbox()
    Dim last As Long = imap.GetAll().Last()

    imap.GmailLabelMessageByUID(last, FolderFlag.XStarred.Name)

    imap.Close()
End Using

Imap.CopyByUID method

The second method basis on the fact that Gmail treats labels as regular IMAP folders.
You just need to know correct folder name and copy the message to this folder.

You can use CommonFolders class to get common folders:

// C#

using (Imap imap = new Imap())
{
    imap.ConnectSSL("imap.gmail.com");
    imap.Login("pat@gmail.com", "password");

    List<FolderInfo> folders = imap.GetFolders();

    imap.SelectInbox();
    long last = imap.GetAll().Last();

    imap.CopyByUID(last, new CommonFolders(folders).Starred);

    imap.Close();
}

' VB.NET

Using imap As New Imap()
    imap.ConnectSSL("imap.gmail.com")
    imap.Login("pat@gmail.com", "password")

    Dim folders As List(Of FolderInfo) = imap.GetFolders()

    imap.SelectInbox()
    Dim last As Long = imap.GetAll().Last()

    imap.CopyByUID(last, New CommonFolders(folders).Starred)

    imap.Close()
End Using

As such, labels can be modified using the standard IMAP commands, CreateFolder, RenameFolder, and DeleteFolder, that act on folders.

System labels, which are labels created by Gmail, are reserved and prefixed by “[Gmail]” or “[GoogleMail]” in the list of labels.

// C#

using (Imap imap = new Imap())
{
    imap.ConnectSSL("imap.gmail.com");
    imap.Login("pat@gmail.com", "password");

    List<FolderInfo> folders = imap.GetFolders();
    List<FolderInfo> system = folders.FindAll(x => x.Name.StartsWith("[Gmail]"));
    List<FolderInfo> user = folders.FindAll(x => !x.Name.StartsWith("[Gmail]"));

    Console.WriteLine("System labels:");
    system.ForEach(x => Console.WriteLine(x.Name));
    Console.WriteLine();
    Console.WriteLine("User labels:");
    user.ForEach(x => Console.WriteLine(x.Name));

    imap.Close();
}

' VB.NET

Using imap As New Imap()
    imap.ConnectSSL("imap.gmail.com")
    imap.Login("pat@gmail.com", "password")

    Dim folders As List(Of FolderInfo) = imap.GetFolders()
    Dim system As List(Of FolderInfo) =
        folders.FindAll(Function(x) x.Name.StartsWith("[Gmail]"))
    Dim user As List(Of FolderInfo) =
        folders.FindAll(Function(x) Not x.Name.StartsWith("[Gmail]"))

    Console.WriteLine("System labels:")
    system.ForEach(Function(x) Console.WriteLine(x.Name))
    Console.WriteLine()
    Console.WriteLine("User labels:")
    user.ForEach(Function(x) Console.WriteLine(x.Name))

    imap.Close()
End Using

Here is the output:


System labels:
[Gmail]
[Gmail]/All Mail
[Gmail]/Drafts
[Gmail]/Sent Mail
[Gmail]/Spam
[Gmail]/Starred
[Gmail]/Trash



User labels:
my label
my label/nested
my second label


IMail object exposes VCards collection that contains all vCard business cards that were found while parsing an email.

You can use both IMAP or POP3 protocol to download email from the server.

Here’s the simple sample showing how to process VCard business cards:

// C#

IMail email = new MailBuilder().CreateFromEml(client.GetMessageByUID(uid));

foreach (VCard vCard in email.VCards)
{

    Console.WriteLine("first name: " + vCard.Name.FirstName);
    Console.WriteLine("last name: " + vCard.Name.LastName);
    Console.WriteLine("full name: " + vCard.FullName);

    Console.WriteLine("email: " + vCard.Email);
    Console.WriteLine("work phone: " + vCard.WorkPhone);
    Console.WriteLine("home phone: " + vCard.HomePhone);

    if (vCard.WorkAddress != null)
    {
        Console.WriteLine(vCard.WorkAddress.PostOfficeBox);
        Console.WriteLine(vCard.WorkAddress.ApartmentNumber);
        Console.WriteLine(vCard.WorkAddress.Street);
        Console.WriteLine(vCard.WorkAddress.City);
        Console.WriteLine(vCard.WorkAddress.Region);
        Console.WriteLine(vCard.WorkAddress.PostalCode);
        Console.WriteLine(vCard.WorkAddress.Country);
    }
    if (vCard.HomeAddress != null)
    {
        //...
    }

    foreach (VCardPhone phone in vCard.Phones)
    {
        Console.WriteLine("phone: " + phone.Value);
    }
    foreach (VCardAddress address in vCard.Addresses)
    {
        Console.WriteLine("street: " + address.Street);
    }
    foreach (VCardEmail mail in vCard.Emails)
    {
        Console.WriteLine("email: " + mail.Value);
    }
}

' VB.NET

Dim email As IMail = New MailBuilder().CreateFromEml(client.GetMessageByUID(uid))

For Each vCard As VCard In email.VCards

	Console.WriteLine("first name: " + vCard.Name.FirstName)
	Console.WriteLine("last name: " + vCard.Name.LastName)
	Console.WriteLine("full name: " + vCard.FullName)

	Console.WriteLine("email: " + vCard.Email)
	Console.WriteLine("work phone: " + vCard.WorkPhone)
	Console.WriteLine("home phone: " + vCard.HomePhone)

	If vCard.WorkAddress IsNot Nothing Then
		Console.WriteLine(vCard.WorkAddress.PostOfficeBox)
		Console.WriteLine(vCard.WorkAddress.ApartmentNumber)
		Console.WriteLine(vCard.WorkAddress.Street)
		Console.WriteLine(vCard.WorkAddress.City)
		Console.WriteLine(vCard.WorkAddress.Region)
		Console.WriteLine(vCard.WorkAddress.PostalCode)
		Console.WriteLine(vCard.WorkAddress.Country)
	End If
			'...
	If vCard.HomeAddress IsNot Nothing Then
	End If

	For Each phone As VCardPhone In vCard.Phones
		Console.WriteLine("phone: " + phone.Value)
	Next
	For Each address As VCardAddress In vCard.Addresses
		Console.WriteLine("street: " + address.Street)
	Next
	For Each mail As VCardEmail In vCard.Emails
		Console.WriteLine("email: " + mail.Value)
	Next
Next

You can learn here how to send email with VCard.

• Create new application that references Mail.dll IMAP component.
• Configure Gmail to allow IMAP access.
• Connect and login to Gmail using SSL secured channel.
• Search and download unseen emails.
• Parse downloaded email messages.
• and finally access most common email properties like subject, sender, attachments.

Enjoy:

IMail object exposes Appointments collection that contains all appointments that were found while parsing an email.

You can use both IMAP or POP3 protocol to download email from the server.

Here’s the simple sample showing how to process iCalendar appointments:

// C#

IMail email = new MailBuilder().CreateFromEml(client.GetMessageByUID(uid));

foreach (Appointment appointment in email.Appointments)
{
    if (appointment.Method == Method.Request)
    {
        // appointment was created
        string summary = appointment.Event.Summary;
        DateTime? start = appointment.Event.Start;
        DateTime? end = appointment.Event.End;
        string location = appointment.Event.Location;

        Console.WriteLine("{0} at {1} ({2}-{3})", summary, location, start, end);

        foreach (Participant participant in appointment.Event.Participants)
        {
            Console.WriteLine("Common name: " + participant.Cn);
            Console.WriteLine("Email: " + participant.Email);
            Console.WriteLine("Participation status: " + participant.Status);
        }
    }
    else if (appointment.Method == Method.Cancel)
    {
        // appointment was canceled
        Console.WriteLine("Event was cancelled: " + appointment.Event.UID);

    }
    else if (appointment.Method == Method.Reply)
    {
        // someone replied to the request
        foreach (Participant participant in appointment.Event.Participants)
        {
            if (participant.Status == ParticipationStatus.Accepted)
                Console.WriteLine("Event was accepted by: " + participant.Email);
            else if (participant.Status == ParticipationStatus.Declined)
                Console.WriteLine("Event was declined by: " + participant.Email);
        }

    }
}

' VB.NET

Dim email As IMail = New MailBuilder().CreateFromEml(client.GetMessageByUID(uid))

For Each appointment As Appointment In email.Appointments
	If appointment.Method = Method.Request Then
		' appointment was created
		Dim summary As String = appointment.[Event].Summary
		Dim start As System.Nullable(Of DateTime) = appointment.[Event].Start
		Dim [end] As System.Nullable(Of DateTime) = appointment.[Event].[End]
		Dim location As String = appointment.[Event].Location

		Console.WriteLine("{0} at {1} ({2}-{3})", summary, location, start, [end])

		For Each participant As Participant In appointment.[Event].Participants
			Console.WriteLine("Common name: " + participant.Cn)
			Console.WriteLine("Email: " + participant.Email)
			Console.WriteLine("Participation status: " + participant.Status)
		Next
	ElseIf appointment.Method = Method.Cancel Then
		' appointment was canceled

		Console.WriteLine("Event was cancelled: " + appointment.[Event].UID)
	ElseIf appointment.Method = Method.Reply Then
		' someone replied to the request
		For Each participant As Participant In appointment.[Event].Participants
			If participant.Status = ParticipationStatus.Accepted Then
				Console.WriteLine("Event was accepted by: " + participant.Email)
			ElseIf participant.Status = ParticipationStatus.Declined Then
				Console.WriteLine("Event was declined by: " + participant.Email)
			End If

		Next
	End If
Next

You need to use DeleteMessageByUID method. Messages will be still available in All Mail folder.

// C#

using(Imap imap = new Imap())
{
	imap.ConnectSSL("imap.gmail.com");
	imap.Login("user", "password");

	// Find all emails we want to delete
	imap.SelectInbox();
	List<long> uids = imap.Search(
		Expression.Subject("email to archive"));

	imap.DeleteMessageByUID(uids);

	imap.Close();
}

' VB.NET

Using imap As New Imap()
	imap.ConnectSSL("imap.gmail.com")
	imap.Login("user@gmail.com", "password")

	' Find all emails we want to delete
	imap.SelectInbox()
	Dim uids As List(Of Long) = imap.Search(_
		Expression.Subject("email to archive"))

	imap.DeleteMessageByUID(uids)

	imap.Close()
End Using

1. Sign in to Gmail.
2. Click the gear icon in the upper-right and select Mail settings .
3. Click Forwarding and POP/IMAP.
4. Select Enable IMAP.
5. Now you are able to connect to your Gmail account with Mail.dll IMAP library.

Remember that Gmail only allows secure SSL connections so you need to use ConnectSSL method.

Now you can download emails from Gmail using IMAP protocol.

OAuth is an open protocol to allow secure API authorization in a simple and standard method from desktop and web applications.

In this post I’ll show how to access Gmail account using 3-legged OAuth authentication method with Mail.dll IMAP component. The key advantage of this method is that it allows an application to access user email without knowing user’s password.

You can read more on OAuth authentication with Google accounts here:
http://code.google.com/apis/accounts/docs/OAuth_ref.html

Gmail IMAP and SMTP using OAuth:
http://code.google.com/apis/gmail/oauth/protocol.html

If your application/website is not registered, you should use following key and secret:
consumer key: “anonymous”
consumer secret: “anonymous”

Remember to add reference to Mail.dll and appropriate namespaces.

// C#

using Limilabs.Client.IMAP;
using Limilabs.Client.Authentication;
using Limilabs.Client.Authentication.Google;

const string userEmailAccount = "pat@gmail.com";
const string consumerKey = "anonymous";
const string consumerSecret = "anonymous";

GmailOAuth oauth = new GmailOAuth(consumerKey, consumerSecret);

string url = oauth.GetAuthorizationUrl("http://localhost:64119/");

// ASP.NET client:
// Save oauth in permanent storage:
// Cache[oauth.RequestToken.Token] = oauth;

// Windows client:
Process.Start(url);

// ASP.NET client:
// Response.Redirect(url);

// Windows client with url:
string rawReturnUrl = Console.ReadLine();
ReturnUrl returnUrl = new ReturnUrl(rawReturnUrl);
oauth.GetAccessToken(returnUrl.OAuthVerifier);

// Windows client with verification code (oob):
// string oauthVerifier = HttpUtility.UrlDecode(Console.ReadLine());
// oauth.GetAccessToken(oauthVerifier);

// ASP.NET client:
// ReturnUrl returnUrl = new ReturnUrl(Request.RawUrl);
// Retrieve oauth from permanent storage:
// GmailOAuth oauth = Cache[returnUrl.OAuthToken]
// oauth.GetAccessToken(returnUrl.OAuthVerifier);

using (Imap client = new Imap())
{
    client.ConnectSSL("imap.gmail.com");
    string oauthImapKey = oauth.GetXOAuthKeyForImap();
    client.LoginOAUTH(oauthImapKey);

    // Now you can access user's emails
    //...

    client.Close();
    oauth.RevokeToken(oauthImapKey);
}

1.
GmailOAuth.GetAuthorizationUrl method returns url you should redirect your user to, so he can authorize access.
As you can see, Mail.dll is asking for access to user’s email information and Gmail access:

2.
If you don’t specify callback parameter, user will have to manually copy&paste the token to your application (oob):

In case of a web project, you can specify a web address on your website. oauth_verifier will be included as the redirection url parameter.

After the redirection, your website/application needs to read oauth_verifier query parameter:

3.
GmailOAuth.GetAccessToken method authorizes the token.

4.
GmailOAuth.GetXOAuthKeyForImap method uses Google API to get the email address of the user, and generates XOAuth key for IMAP protocol (you can use GetXOAuthKeyForSmtp for SMTP).

5.
GmailOAuth.RevokeToken method revokes XOAuth key, so no further access can be made with it.

…and finally VB.NET version of the code:

' VB.NET

Imports Limilabs.Client.IMAP
Imports Limilabs.Client.Authentication
Imports Limilabs.Client.Authentication.Google

Const  userEmailAccount As String = "pat@gmail.com"
Const  consumerKey As String = "anonymous"
Const  consumerSecret As String = "anonymous"

Dim oauth As New GmailOAuth(consumerKey, consumerSecret)

Dim url As String = oauth.GetAuthorizationUrl("http://localhost:64119/")

' ASP.NET client:
' Save oauth in permanent storage:
' Cache[oauth.RequestToken.Token] = oauth;

' Windows client:
Process.Start(url)

' ASP.NET client:
' Response.Redirect(url)

' Windows client with url:
Dim rawReturnUrl As String = Console.ReadLine()
Dim returnUrl As New ReturnUrl(rawReturnUrl)
oauth.GetAccessToken(returnUrl.OAuthVerifier)

' Windows client with verification code (oob):
' Dim oauthVerifier As String = HttpUtility.UrlDecode(Console.ReadLine())
' oauth.GetAccessToken(oauthVerifier)

' ASP.NET client:
' Dim returnUrl As New ReturnUrl(Request.RawUrl)
' Retrive oauth from permanent storage:
' Dim oauth As GmailOAuth = Cache(returnUrl.OAuthToken)
' oauth.GetAccessToken(returnUrl.OAuthVerifier)

Using client As New Imap()
	client.ConnectSSL("imap.gmail.com")
	Dim oauthImapKey As String = oauth.GetXOAuthKeyForImap()
	client.LoginOAUTH(oauthImapKey)

	' Now you can access user's emails
	'...

	client.Close()
	oauth.RevokeToken(oauthImapKey)
End Using