SendCompletedEventHandler Delegate
.NET Framework (current version)
Represents the method that will handle the SendCompleted event.
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
Available since 2.0
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