Install-Package Google.Apis.Auth
Install-Package Google.Apis.Oauth2.v2

Update-Package

Install-Package MailBee.NET

• C#
• VB

using System;
using System.Threading;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Oauth2.v2;
using Google.Apis.Oauth2.v2.Data;
using Google.Apis.Services;
using MailBee;
using MailBee.ImapMail;

// This program shows how to issue, refresh and use Google access tokens for IMAP access to a Gmail mailbox.
//
// To run this program, select "GmailEasyLogin" in Project / project's Properties / Application tab / Startup object.
public class GmailEasyLogin
{
	public static void Main(string[] args)
	{
		// Request Gmail IMAP/SMTP scope and the e-mail address scope.
		string[] scopes = new string[] { "https://mail.google.com/", "https://www.googleapis.com/auth/userinfo.email" };

		Console.WriteLine("Requesting authorization");
		UserCredential credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
			new ClientSecrets
			{
				ClientId = "Your Client ID, like 0123-abcd.apps.googleusercontent.com",
				ClientSecret = "Your Client Secret, like 0a1b2c3d",
			},
			 scopes,
			 "user",
			 CancellationToken.None).Result;
		Console.WriteLine("Authorization granted or not required (if the saved access token already available)");

		if (credential.Token.IsExpired(credential.Flow.Clock))
		{
			Console.WriteLine("The access token has expired, refreshing it");
			if (credential.RefreshTokenAsync(CancellationToken.None).Result)
			{
				Console.WriteLine("The access token is now refreshed");
			}
			else
			{
				Console.WriteLine("The access token has expired but we can't refresh it :(");
				return;
			}
		}
		else
		{
			Console.WriteLine("The access token is OK, continue");
		}

		Console.WriteLine("Requesting the e-mail address of the user from Google");

		// Sometimes, you may also need to set Initializer.ApplicationName property.
		// In our tests, setting just Initializer.HttpClientInitializer was enough for Google.
		Oauth2Service oauthService = new Oauth2Service(
			new BaseClientService.Initializer() { HttpClientInitializer = credential });

		// Userinfo.Get may crash if you run the app under debugger (a bug in Google API).
		// If this happens, use "Start without debugging" instead.
		Userinfo userInfo = oauthService.Userinfo.Get().ExecuteAsync().Result;
		string userEmail = userInfo.Email;
		Console.WriteLine("E-mail address is " + userEmail);

		// Build XOAUTH2 token. Can be used with Gmail IMAP or SMTP.
		string xoauthKey = OAuth2.GetXOAuthKeyStatic(userEmail, credential.Token.AccessToken);

		// Uncomment and set your key if you haven't specified it in app.config or Windows registry.
		// MailBee.Global.LicenseKey = "Your MNXXX-XXXX-XXXX key here";

		// Finally, use MailBee.NET to list the number of e-mails in Inbox.

		Imap imp = new Imap();

		// Logging is not necessary but useful for debugging.
		imp.Log.Enabled = true;
		imp.Log.Filename = @"C:\Temp\log.txt";
		imp.Log.HidePasswords = false;
		imp.Log.Clear();

		imp.Connect("imap.gmail.com");

		// This is the where IMAP XOAUTH2 actually occurs.
		imp.Login(null, xoauthKey, AuthenticationMethods.SaslOAuth2,
			MailBee.AuthenticationOptions.None, null);

		// If we're here, we're lucky.
		imp.SelectFolder("INBOX");
		Console.WriteLine(imp.MessageCount.ToString() + " e-mails in Inbox");
		imp.Disconnect();
	}
}

Imports System.Threading
Imports Google.Apis.Auth.OAuth2
Imports Google.Apis.Oauth2.v2
Imports Google.Apis.Oauth2.v2.Data
Imports Google.Apis.Services
Imports MailBee
Imports MailBee.ImapMail

' This program shows how to issue, refresh and use Google access tokens for IMAP access to a Gmail mailbox.
'
' To run this program, select "GmailEasyLogin" in Project / project's Properties / Application tab / Startup object.
Public Class GmailEasyLogin
	Public Shared Sub Main(args As String())
		' Request Gmail IMAP/SMTP scope and the e-mail address scope.
		Dim scopes As String() = New String() {"https://mail.google.com/", "https://www.googleapis.com/auth/userinfo.email"}

		Console.WriteLine("Requesting authorization")
		Dim credential As UserCredential = GoogleWebAuthorizationBroker.AuthorizeAsync(New ClientSecrets() With { _
			.ClientId = "Your Client ID, like 0123-abcd.apps.googleusercontent.com", _
			.ClientSecret = "Your Client Secret, like 0a1b2c3d" _
		}, scopes, "user", CancellationToken.None).Result
		Console.WriteLine("Authorization granted or not required (if the saved access token already available)")

		If credential.Token.IsExpired(credential.Flow.Clock) Then
			Console.WriteLine("The access token has expired, refreshing it")
			If credential.RefreshTokenAsync(CancellationToken.None).Result Then
				Console.WriteLine("The access token is now refreshed")
			Else
				Console.WriteLine("The access token has expired but we can't refresh it :(")
				Return
			End If
		Else
			Console.WriteLine("The access token is OK, continue")
		End If

		Console.WriteLine("Requesting the e-mail address of the user from Google")

		' Sometimes, you may also need to set Initializer.ApplicationName property.
		' In our tests, setting just Initializer.HttpClientInitializer was enough for Google.
		Dim oauthService As New Oauth2Service(New BaseClientService.Initializer() With { _
			.HttpClientInitializer = credential _
		})

		' Userinfo.Get may crash if you run the app under debugger (a bug in Google API).
		' If this happens, use "Start without debugging" instead.
		Dim userInfo As Userinfo = oauthService.Userinfo.Get().ExecuteAsync().Result
		Dim userEmail As String = userInfo.Email
		Console.WriteLine("E-mail address is " & userEmail)

		' Build XOAUTH2 token. Can be used with Gmail IMAP or SMTP.
		Dim xoauthKey As String = OAuth2.GetXOAuthKeyStatic(userEmail, credential.Token.AccessToken)

		' Uncomment and set your key if you haven't specified it in app.config or Windows registry.
		' MailBee.Global.LicenseKey = "Your MNXXX-XXXX-XXXX key here"

		' Finally, use MailBee.NET to list the number of e-mails in Inbox.

		Dim imp As New Imap()

		' Logging is not necessary but useful for debugging.
		imp.Log.Enabled = True
		imp.Log.Filename = "C:\Temp\log.txt"
		imp.Log.HidePasswords = False
		imp.Log.Clear()

		imp.Connect("imap.gmail.com")

		' This is the where IMAP XOAUTH2 actually occurs.
		imp.Login(Nothing, xoauthKey, AuthenticationMethods.SaslOAuth2, MailBee.AuthenticationOptions.None, Nothing)

		' If we're here, we're lucky.
		imp.SelectFolder("INBOX")
		Console.WriteLine(imp.MessageCount & " e-mails in Inbox")
		imp.Disconnect()
	End Sub
End Class

• C#
• VB

using System;
using System.Threading;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Auth.OAuth2.Responses;
using Google.Apis.Util.Store;
using Google.Apis.Services;

// These two are required only if you want to get the e-mail address of the user (with Oauth2Service class).
using Google.Apis.Oauth2.v2;
using Google.Apis.Oauth2.v2.Data;

using MailBee;
using MailBee.ImapMail;
using MailBee.SmtpMail;

// This program shows how to issue, refresh, delete, revoke and use Google access tokens for IMAP and SMTP access to a Gmail mailbox.
//
// To run this program, select "GmailLogin" in Project / project's Properties / Application tab / Startup object.
public class GmailLogin
{
	public static void Main(string[] args)
	{
		// You get these in Google Developer Console.
		string yourAppClientID = "Your Client ID, like 0123-abcd.apps.googleusercontent.com";
		string yourAppClientSecret = "Your Client Secret, like 0a1b2c3d";

		// If you want to clear the saved token (if any) to force Google to show authorization screen again,
		// set clearSavedToken to true. Note that the code below only removes the token from the local storage,
		// Google server still remembers it. Deleting a token just locally without revoking it on Google server
		// makes a little practical sense but can be useful for debugging, such as when your local token became
		// invalid: typically happens during development when you issue such many tokens that Google starts to forget
		// them and your local token no longer corresponds to its counterpart on Google server (even revoking such
		// token will fail).
		// If your purpose is to invalidate a working token everywhere (delete from both local storage and Google server),
		// use UserCredential.RevokeTokenAsync (for that, in the end of this sample, set revokeToken to true).
		bool clearSavedToken = false;
		if (clearSavedToken)
		{
			// If there is no saved token (e.g. Google authorization screen has never been shown for this user),
			// the code below will do nothing. No exception will occur. If the token is there, Google API will delete
			// C:\Users\<YourWindowsUser>\AppData\Roaming\Google.Apis.Auth\Google.Apis.Auth.OAuth2.Responses.TokenResponse-user
			// file (the exact path may vary depending on your OS and Google API version). Without the stored token
			// subsequent GoogleWebAuthorizationBroker.AuthorizeAsync call will open the browser window asking for
			// authorization.
			// Note that there still be a difference in authorization window between two situations: when
			// you actually request authorization for the first time and when you deleted the previous token locally
			// and now force Google to request authorization again. In second case Google still remembers that it already
			// authorized this application to access your user and it will just ask the user that the application wants
			// Offline access. In the first case Google will ask for the specified scopes (full access to your mailbox
			// and e-mail address).
			FileDataStore ds = new FileDataStore(GoogleWebAuthorizationBroker.Folder);
			ds.DeleteAsync<TokenResponse>("user").Wait();
		}

		// Here you should specify the user's e-mail address if you already know it (for instance, from
		// your user's input). If you don't set the e-mail address here, MailBee.NET will ask Google for it
		// but this will require the user to grant extra permissions to the application during the authorization.
		string userEmail = null;

		// Gmail supports a number of scopes. This one is required for IMAP/SMTP access.
		string gmailScope = "https://mail.google.com/";

		string[] scopes;

		// We set only a Gmail scope if we don't need the user's email address (when it's already set).
		// Otherwise, we need to add another scope to determine the user's email address.
		if (userEmail != null)
		{
			scopes = new string[1];
		}
		else
		{
			scopes = new string[2];
		}
		scopes[0] = gmailScope;

		// Adding "https://www.googleapis.com/auth/userinfo.email" causes the app to request more permissions from the user
		// but lets us get the e-mail address automatically. Otherwise, you'll need to get the e-mail address
		// by other means, such as to ask it from the user.
		if (userEmail == null)
		{
			scopes[1] = "https://www.googleapis.com/auth/userinfo.email";
		}

		Console.WriteLine("Requesting authorization");
		UserCredential credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
			new ClientSecrets
			{
				ClientId = yourAppClientID,
				ClientSecret = yourAppClientSecret,
			},
			 scopes,
			 "user",
			 CancellationToken.None).Result;
		Console.WriteLine("Authorization granted or not required (if the saved access token already available)");

		if (credential.Token.IsExpired(credential.Flow.Clock))
		{
			Console.WriteLine("The access token has expired, refreshing it");
			if (credential.RefreshTokenAsync(CancellationToken.None).Result)
			{
				Console.WriteLine("The access token is now refreshed");
			}
			else
			{
				Console.WriteLine("The access token has expired but we can't refresh it :(");
				return;
			}
		}
		else
		{
			Console.WriteLine("The access token is OK, continue");
		}

		// Here we autodetect the user's email address with Google+ API. This autodetection is not required
		// if you already know the user's email address from other sources (like the user's input).
		// Also, even if you do ask for the email address, it's not required to do this every time you access
		// the Google mailbox of that user. For instance, you can do this just once and then store the e-mail
		// address locally. This will spare you one HTTP request per each mailbox access and increase performance.
		if (userEmail == null)
		{
			Console.WriteLine("Requesting the e-mail address of the user from Google");

			// Sometimes, you may also need to set Initializer.ApplicationName property.
			// In our tests, setting just Initializer.HttpClientInitializer was enough for Google.
			Oauth2Service oauthService = new Oauth2Service(
				new BaseClientService.Initializer() { HttpClientInitializer = credential });

			Userinfo userInfo = oauthService.Userinfo.Get().ExecuteAsync().Result;
			userEmail = userInfo.Email;
			Console.WriteLine("E-mail address is " + userEmail);
		}

		string xoauthKey = OAuth2.GetXOAuthKeyStatic(userEmail, credential.Token.AccessToken);

		bool useImap = true; // Set to false to use SMTP (send e-mail) instead of IMAP (check Inbox).

		// Uncomment and set your key if you haven't specified it in app.config or Windows registry.
		// MailBee.Global.LicenseKey = "Your MNXXX-XXXX-XXXX key here";

		if (useImap)
		{
			Imap imp = new Imap();

			// Logging is not necessary but useful for debugging.
			imp.Log.Enabled = true;
			imp.Log.Filename = @"C:\Temp\log.txt";
			imp.Log.HidePasswords = false;
			imp.Log.Clear();

			imp.Connect("imap.gmail.com");
			imp.Login(null, xoauthKey, AuthenticationMethods.SaslOAuth2,
				MailBee.AuthenticationOptions.None, null);
			imp.SelectFolder("INBOX");
			Console.WriteLine(imp.MessageCount.ToString() + " e-mails in Inbox");
			imp.Disconnect();
		}
		else
		{
			Smtp mailer = new Smtp();
			mailer.SmtpServers.Add("smtp.gmail.com", null, xoauthKey, AuthenticationMethods.SaslOAuth2);

			// Logging is not necessary but useful for debugging.
			mailer.Log.Enabled = true;
			mailer.Log.Filename = @"C:\Temp\log.txt";
			mailer.Log.HidePasswords = false;
			mailer.Log.Clear();

			mailer.From.Email = userEmail;
			mailer.To.Add(userEmail);
			mailer.Subject = "empty email to myself";
			mailer.Send();
			Console.WriteLine("E-mail sent");
		}

		// Set revokeToken to true to invalidate the token if you want to disconnect the user from your application.
		// Revoking a token deletes it from Google server and from local storage. Strictly speaking, Google may remember
		// even revoked tokens so there can be a way to reactivate a revoked token but this sample doesn't go that deep.
		//
		// This code revokes the token which was already retrieved with GoogleWebAuthorizationBroker.AuthorizeAsync method.
		// This can be useful if you want to use it instantly - you retrieved the token, used it, and then want to forget it.
		// In case if you need to revoke an existing token which was retrieved earlier (not in the current session) you can
		// use GmailRevokeToken sample code. It also shows the alternate way of how to refresh a previously stored token.
		//
		// Note: revoking tokens only works for valid tokens. If your token is not known to Google (for instance, you issued
		// more than 25 new tokens since then), it will fail. Use local-only deletion (in the beginning of this sample) for that.
		// Also, revoking won't work for expired tokens. If it's expired and you want to test revoking, refresh it first.
		// You may ask what's the purpose of revoking an access token if it's already expired and cannot be used anyway. However,
		// an expired access token can be refreshed in case if you have its refresh token counterpart. But if the access token is
		// revoked, its refresh token will also be revoked and thus can no longer be used for access token renewal.
		bool revokeToken = false;
		if (revokeToken)
		{
			credential.RevokeTokenAsync(CancellationToken.None).Wait();
		}
	}
}

Imports System.Threading
Imports Google.Apis.Auth.OAuth2
Imports Google.Apis.Auth.OAuth2.Responses
Imports Google.Apis.Util.Store
Imports Google.Apis.Services

' These two are required only if you want to get the e-mail address of the user (with Oauth2Service class).
Imports Google.Apis.Oauth2.v2
Imports Google.Apis.Oauth2.v2.Data

Imports MailBee
Imports MailBee.ImapMail
Imports MailBee.SmtpMail

' This program shows how to issue, refresh, delete, revoke and use Google access tokens for IMAP and SMTP access to a Gmail mailbox.
'
' To run this program, select "GmailLogin" in Project / project's Properties / Application tab / Startup object.
Public Class GmailLogin
	Public Shared Sub Main(args As String())
		' You get these in Google Developer Console.
		Dim yourAppClientID As String = "Your Client ID, like 0123-abcd.apps.googleusercontent.com"
		Dim yourAppClientSecret As String = "Your Client Secret, like 0a1b2c3d"

		' If you want to clear the saved token (if any) to force Google to show authorization screen again,
		' set clearSavedToken to true. Note that the code below only removes the token from the local storage,
		' Google server still remembers it. Deleting a token just locally without revoking it on Google server
		' makes a little practical sense but can be useful for debugging, such as when your local token became
		' invalid: typically happens during development when you issue such many tokens that Google starts to forget
		' them and your local token no longer corresponds to its counterpart on Google server (even revoking such
		' token will fail).
		' If your purpose is to invalidate a working token everywhere (delete from both local storage and Google server),
		' use UserCredential.RevokeTokenAsync (for that, in the end of this sample, set revokeToken to true).
		Dim clearSavedToken As Boolean = False
		If clearSavedToken Then
			' If there is no saved token (e.g. Google authorization screen has never been shown for this user),
			' the code below will do nothing. No exception will occur. If the token is there, Google API will delete
			' C:\Users\<YourWindowsUser>\AppData\Roaming\Google.Apis.Auth\Google.Apis.Auth.OAuth2.Responses.TokenResponse-user
			' file (the exact path may vary depending on your OS and Google API version). Without the stored token
			' subsequent GoogleWebAuthorizationBroker.AuthorizeAsync call will open the browser window asking for
			' authorization.
			' Note that there still be a difference in authorization window between two situations: when
			' you actually request authorization for the first time and when you deleted the previous token locally
			' and now force Google to request authorization again. In second case Google still remembers that it already
			' authorized this application to access your user and it will just ask the user that the application wants
			' Offline access. In the first case Google will ask for the specified scopes (full access to your mailbox
			' and e-mail address).
			Dim ds As New FileDataStore(GoogleWebAuthorizationBroker.Folder)
			ds.DeleteAsync(Of TokenResponse)("user").Wait()
		End If

		' Here you should specify the user's e-mail address if you already know it (for instance, from
		' your user's input). If you don't set the e-mail address here, MailBee.NET will ask Google for it
		' but this will require the user to grant extra permissions to the application during the authorization.
		Dim userEmail As String = Nothing

		' Gmail supports a number of scopes. This one is required for IMAP/SMTP access.
		Dim gmailScope As String = "https://mail.google.com/"

		Dim scopes As String()

		' We set only a Gmail scope if we don't need the user's email address (when it's already set).
		' Otherwise, we need to add another scope to determine the user's email address.
		If userEmail IsNot Nothing Then
			scopes = New String(0) {}
		Else
			scopes = New String(1) {}
		End If
		scopes(0) = gmailScope

		' Adding "https://www.googleapis.com/auth/userinfo.email" causes the app to request more permissions from the user
		' but lets us get the e-mail address automatically. Otherwise, you'll need to get the e-mail address
		' by other means, such as to ask it from the user.
		If userEmail Is Nothing Then
			scopes(1) = "https://www.googleapis.com/auth/userinfo.email"
		End If

		Console.WriteLine("Requesting authorization")
		Dim credential As UserCredential = GoogleWebAuthorizationBroker.AuthorizeAsync(New ClientSecrets() With { _
			.ClientId = yourAppClientID, _
			.ClientSecret = yourAppClientSecret _
		}, scopes, "user", CancellationToken.None).Result
		Console.WriteLine("Authorization granted or not required (if the saved access token already available)")

		If credential.Token.IsExpired(credential.Flow.Clock) Then
			Console.WriteLine("The access token has expired, refreshing it")
			If credential.RefreshTokenAsync(CancellationToken.None).Result Then
				Console.WriteLine("The access token is now refreshed")
			Else
				Console.WriteLine("The access token has expired but we can't refresh it :(")
				Return
			End If
		Else
			Console.WriteLine("The access token is OK, continue")
		End If

		' Here we autodetect the user's email address with Google+ API. This autodetection is not required
		' if you already know the user's email address from other sources (like the user's input).
		' Also, even if you do ask for the email address, it's not required to do this every time you access
		' the Google mailbox of that user. For instance, you can do this just once and then store the e-mail
		' address locally. This will spare you one HTTP request per each mailbox access and increase performance.
		If userEmail Is Nothing Then
			Console.WriteLine("Requesting the e-mail address of the user from Google")

			' Sometimes, you may also need to set Initializer.ApplicationName property.
			' In our tests, setting just Initializer.HttpClientInitializer was enough for Google.
			Dim oauthService As New Oauth2Service(New BaseClientService.Initializer() With { _
				.HttpClientInitializer = credential _
			})

			Dim userInfo As Userinfo = oauthService.Userinfo.Get().ExecuteAsync().Result
			userEmail = userInfo.Email
			Console.WriteLine("E-mail address is " & userEmail)
		End If

		Dim xoauthKey As String = OAuth2.GetXOAuthKeyStatic(userEmail, credential.Token.AccessToken)

		Dim useImap As Boolean = True ' Set to false to use SMTP (send e-mail) instead of IMAP (check Inbox).

		' Uncomment and set your key if you haven't specified it in app.config or Windows registry.
		' MailBee.Global.LicenseKey = "Your MNXXX-XXXX-XXXX key here"

		If useImap Then
			Dim imp As New Imap()

			' Logging is not necessary but useful for debugging.
			imp.Log.Enabled = True
			imp.Log.Filename = "C:\Temp\log.txt"
			imp.Log.HidePasswords = False
			imp.Log.Clear()

			imp.Connect("imap.gmail.com")
			imp.Login(Nothing, xoauthKey, AuthenticationMethods.SaslOAuth2, MailBee.AuthenticationOptions.None, Nothing)
			imp.SelectFolder("INBOX")
			Console.WriteLine(imp.MessageCount.ToString() & " e-mails in Inbox")
			imp.Disconnect()
		Else
			Dim mailer As New Smtp()
			mailer.SmtpServers.Add("smtp.gmail.com", Nothing, xoauthKey, AuthenticationMethods.SaslOAuth2)

			' Logging is not necessary but useful for debugging.
			mailer.Log.Enabled = True
			mailer.Log.Filename = "C:\Temp\log.txt"
			mailer.Log.HidePasswords = False
			mailer.Log.Clear()

			mailer.From.Email = userEmail
			mailer.To.Add(userEmail)
			mailer.Subject = "empty email to myself"
			mailer.Send()
			Console.WriteLine("E-mail sent")
		End If

		' Set revokeToken to true to invalidate the token if you want to disconnect the user from your application.
		' Revoking a token deletes it from Google server and from local storage. Strictly speaking, Google may remember
		' even revoked tokens so there can be a way to reactivate a revoked token but this sample doesn't go that deep.
		'
		' This code revokes the token which was already retrieved with GoogleWebAuthorizationBroker.AuthorizeAsync method.
		' This can be useful if you want to use it instantly - you retrieved the token, used it, and then want to forget it.
		' In case if you need to revoke an existing token which was retrieved earlier (not in the current session) you can
		' use GmailRevokeToken sample code. It also shows the alternate way of how to refresh a previously stored token.
		'
		' Note: revoking tokens only works for valid tokens. If your token is not known to Google (for instance, you issued
		' more than 25 new tokens since then), it will fail. Use local-only deletion (in the beginning of this sample) for that.
		' Also, revoking won't work for expired tokens. If it's expired and you want to test revoking, refresh it first.
		' You may ask what's the purpose of revoking an access token if it's already expired and cannot be used anyway. However,
		' an expired access token can be refreshed in case if you have its refresh token counterpart. But if the access token is
		' revoked, its refresh token will also be revoked and thus can no longer be used for access token renewal.
		Dim revokeToken As Boolean = False
		If revokeToken Then
			credential.RevokeTokenAsync(CancellationToken.None).Wait()
		End If
	End Sub
End Class

• C#
• VB

using System;
using System.Threading;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Auth.OAuth2.Flows;
using Google.Apis.Auth.OAuth2.Responses;
using Google.Apis.Util.Store;

// This program shows how to load a previously stored Google access token and revoke it.
//
// To run this program, select "GmailRevokeToken" in Project / project's Properties / Application tab / Startup object.
public class GmailRevokeToken
{
	const string gmailFullAccessScope = "https://mail.google.com/";

	public static void Main(string[] args)
	{
		GoogleAuthorizationCodeFlow.Initializer initializer = new GoogleAuthorizationCodeFlow.Initializer
		{
			ClientSecrets = new ClientSecrets
			{
				ClientId = "Your Client ID, like 0123-abcd.apps.googleusercontent.com",
				ClientSecret = "Your Client Secret, like 0a1b2c3d"
			}
		};
		initializer.DataStore = new FileDataStore(GoogleWebAuthorizationBroker.Folder);
		GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow(initializer);

		Console.WriteLine("Will load the saved access token");
		TokenResponse token = flow.LoadTokenAsync("user", CancellationToken.None).Result;

		if (token == null)
		{
			Console.WriteLine("No saved token found");
		}
		else
		{
			// Revoking an expired token is not possible, we need to refresh it first.
			if (token.IsExpired(flow.Clock))
			{
				Console.WriteLine("Will renew the access token");
				token = flow.RefreshTokenAsync("user", token.RefreshToken, CancellationToken.None).Result;
			}
			else
			{
				Console.WriteLine("Token renewal not needed");
			}

			Console.WriteLine("Will revoke the saved access token now");
			flow.RevokeTokenAsync("user", token.AccessToken, CancellationToken.None).Wait();
			Console.WriteLine("The token revoked");
		}
	}
}

Imports System.Threading
Imports Google.Apis.Auth.OAuth2
Imports Google.Apis.Auth.OAuth2.Flows
Imports Google.Apis.Auth.OAuth2.Responses
Imports Google.Apis.Util.Store

' This program shows how to load a previously stored Google access token and revoke it.
'
' To run this program, select "GmailRevokeToken" in Project / project's Properties / Application tab / Startup object.
Public Class GmailRevokeToken
	Const gmailFullAccessScope As String = "https://mail.google.com/"

	Public Shared Sub Main(args As String())
		Dim initializer As New GoogleAuthorizationCodeFlow.Initializer() With { _
			.ClientSecrets = New ClientSecrets() With { _
				.ClientId = "Your Client ID, like 0123-abcd.apps.googleusercontent.com", _
				.ClientSecret = "Your Client Secret, like 0a1b2c3d" _
			} _
		}
		initializer.DataStore = New FileDataStore(GoogleWebAuthorizationBroker.Folder)
		Dim flow As New GoogleAuthorizationCodeFlow(initializer)

		Console.WriteLine("Will load the saved access token")
		Dim token As TokenResponse = flow.LoadTokenAsync("user", CancellationToken.None).Result

		If token Is Nothing Then
			Console.WriteLine("No saved token found")
		Else
			' Revoking an expired token is not possible, we need to refresh it first.
			If token.IsExpired(flow.Clock) Then
				Console.WriteLine("Will renew the access token")
				token = flow.RefreshTokenAsync("user", token.RefreshToken, CancellationToken.None).Result
			Else
				Console.WriteLine("Token renewal not needed")
			End If

			Console.WriteLine("Will revoke the saved access token now")
			flow.RevokeTokenAsync("user", token.AccessToken, CancellationToken.None).Wait()
			Console.WriteLine("The token revoked")
		End If
	End Sub
End Class