SendCompletedEventHandler Delegate

 
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Represents the method that will handle the SendCompleted event.

Namespace:   System.Net.Mail
Assembly:  System (in System.dll)

Public Delegate Sub SendCompletedEventHandler (
	sender As Object,
	e As AsyncCompletedEventArgs
)

Parameters

sender
Type: System.Object

The source of the event.

e
Type: System.ComponentModel.AsyncCompletedEventArgs

An AsyncCompletedEventArgs containing event data.

The SendCompletedEventHandler delegate is used to handle events that occur when the SmtpClient class finishes asynchronously sending an e-mail message using the SendAsync method.

The following code example demonstrates sending an e-mail message asynchronously. It uses a SendCompletedEventHandler to invoke the SendCompletedCallback method to handle SendCompleted events.


Imports System
Imports System.Net
Imports System.Net.Mail
Imports System.Net.Mime
Imports System.Threading
Imports System.ComponentModel
Namespace Examples.SmptExamples.Async
    Public Class SimpleAsynchronousExample
        Private Shared mailSent As Boolean = False
        Private Shared Sub SendCompletedCallback(ByVal sender As Object, ByVal e As AsyncCompletedEventArgs)
            ' Get the unique identifier for this asynchronous operation.
            Dim token As String = CStr(e.UserState)

            If e.Cancelled Then
                Console.WriteLine("[{0}] Send canceled.", token)
            End If
            If e.Error IsNot Nothing Then
                Console.WriteLine("[{0}] {1}", token, e.Error.ToString())
            Else
                Console.WriteLine("Message sent.")
            End If
            mailSent = True
        End Sub
        Public Shared Sub Main(ByVal args() As String)
            ' Command line argument must the the SMTP host.
            Dim client As New SmtpClient(args(0))
            ' Specify the e-mail sender.
            ' Create a mailing address that includes a UTF8 character
            ' in the display name.
            Dim [from] As New MailAddress("jane@contoso.com", "Jane " & ChrW(&HD8) & " Clayton", System.Text.Encoding.UTF8)
            ' Set destinations for the e-mail message.
            Dim [to] As New MailAddress("ben@contoso.com")
            ' Specify the message content.
            Dim message As New MailMessage([from], [to])
            message.Body = "This is a test e-mail message sent by an application. "
            ' Include some non-ASCII characters in body and subject.
            Dim someArrows As New String(New Char() {ChrW(&H2190), ChrW(&H2191), ChrW(&H2192), ChrW(&H2193)})
            message.Body += Environment.NewLine & someArrows
            message.BodyEncoding = System.Text.Encoding.UTF8
            message.Subject = "test message 1" & someArrows
            message.SubjectEncoding = System.Text.Encoding.UTF8
            ' Set the method that is called back when the send operation ends.
            AddHandler client.SendCompleted, AddressOf SendCompletedCallback
            ' The userState can be any object that allows your callback 
            ' method to identify this send operation.
            ' For this example, the userToken is a string constant.
            Dim userState As String = "test message1"
            client.SendAsync(message, userState)
            Console.WriteLine("Sending message... press c to cancel mail. Press any other key to exit.")
            Dim answer As String = Console.ReadLine()
            ' If the user canceled the send, and mail hasn't been sent yet,
            ' then cancel the pending operation.
            If answer.StartsWith("c") AndAlso mailSent = False Then
                client.SendAsyncCancel()
            End If
            ' Clean up.
            message.Dispose()
            Console.WriteLine("Goodbye.")
        End Sub
    End Class
End Namespace

.NET Framework
Available since 2.0
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