(C# UWP/WinRT) GMail SMTP Send using Previously Obtained OAuth2 Access Token

Demonstrates how to send email using GMail and OAuth2 authentication. This example assumes an OAuth2 access token was previously obtained.

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// See Get GMail SMTP Access Token 
// for sample code showing how to obtain a GMail SMTP access token for desktop apps.

// In this example, our access token was previously saved to the following file which contains JSON like this:
// 	{
// 	 "access_token": "ya39.Ci-XA_C5bGgRDC3UaD-h0_NeL-DVIQnI2gHtBBBHkZzrwlARkwX6R3O0PCDEzRlfaQ",
// 	 "token_type": "Bearer",
// 	 "expires_in": 3600,
// 	 "refresh_token": "1/r_2c_7jddspcdfesrrfKqfXtqo08D6Q-gUU0DsdfVMsx0c"
// 	}
// 
Chilkat.JsonObject json = new Chilkat.JsonObject();
bool success = json.LoadFile("qa_data/tokens/_gmailSmtp.json");
if (success != true) {
    Debug.WriteLine("Failed to load GMail access token file.");
    return;
}

string accessToken = json.StringOf("access_token");

Chilkat.MailMan mailman = new Chilkat.MailMan();

// Set the properties for the GMail SMTP server:
mailman.SmtpHost = "smtp.gmail.com";
mailman.SmtpPort = 587;
mailman.StartTLS = true;

// The SMTP username should be the GMail address of the user's account that authorized your app to send email.
mailman.SmtpUsername = "chilkat.support@gmail.com";
mailman.OAuth2AccessToken = accessToken;

// Create a new email object
Chilkat.Email email = new Chilkat.Email();

email.Subject = "This is a test";
email.Body = "This is a test";
email.From = "Chilkat <chilkat.support@gmail.com>";
email.AddTo("Chilkat Admin","admin@chilkatsoft.com");
// To add more recipients, call AddTo, AddCC, or AddBcc once per recipient.

// Call SendEmail to connect to the SMTP server and send.
// The connection (i.e. session) to the SMTP server remains
// open so that subsequent SendEmail calls may use the
// same connection.  
success = await mailman.SendEmailAsync(email);
if (success != true) {
    Debug.WriteLine(mailman.LastErrorText);
    return;
}

// You may close the connection here.  If the connection is kept open, 
// the next call to mailman.SendEmail will continue using the already-established connection
// (and automatically re-connect if needed).
success = await mailman.CloseSmtpConnectionAsync();
if (success != true) {
    Debug.WriteLine("Connection to SMTP server not closed cleanly.");
}

Debug.WriteLine("Email Sent via GMail with OAuth2 authentication.");