(VB.NET 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"
' 	}
' 
Dim json As New Chilkat.JsonObject
Dim success As Boolean = json.LoadFile("qa_data/tokens/_gmailSmtp.json")
If (success <> True) Then
    Debug.WriteLine("Failed to load GMail access token file.")
    Exit Sub
End If

Dim accessToken As String = json.StringOf("access_token")


Dim mailman As 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
Dim email As 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) Then
    Debug.WriteLine(mailman.LastErrorText)
    Exit Sub
End If


' 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) Then
    Debug.WriteLine("Connection to SMTP server not closed cleanly.")
End If


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