Rappel de classe de courrier électronique asynchrone?

Question

J'essaie de créer une nouvelle classe qui envoie des emails de manière asynchrone. Comment puis-je mettre à jour l'interface utilisateur lorsque le processus est terminé?

classe Email

Private Shared _mailSent As Boolean = False 
Private _mailError As String 
Public Property mailError() As String 
    Get 
     Return _mailError 
    End Get 
    Set(value As String) 
     _mailError = value 
    End Set 
End Property 
Public Property mailSent() As Boolean 
    Get 
     Return _mailSent 
    End Get 
    Set(value As Boolean) 
     _mailSent = value 
    End Set 
End Property 

Private Sub SendCompletedCallback(ByVal sender As Object, ByVal e As AsyncCompletedEventArgs) 
    Dim token As String = e.UserState.ToString() 

    If Not e.Error Is Nothing Then 
     mailError = String.Format("{0} - {1}. {2}", token, e.Error.ToString(), e.UserState.ToString()) 
     mailSent = False 
    Else 
     mailSent = True 
    End If 
End Sub 
Public Sub SendEmail(ByVal eFrom As String, 
        ByVal eTo As String, 
        ByVal eBody As String, 
        ByVal eBodyIsHtml As Boolean, 
        ByVal eSubject As String, 
        Optional ByVal smtpHost As String = "<ip>", 
        Optional ByVal eReplyTo As String = "", 
        Optional ByVal priority As Integer = 1, 
        Optional ByVal eDisplayName As String = "", 
        Optional ByVal eCC As String = "", 
        Optional ByVal eBCC As String = "") 
    Try 
     Dim emailFrom As New MailAddress(eFrom, eDisplayName, Encoding.UTF8) 
     Dim emailTo As New MailAddress(eTo) 
     Dim client As New SmtpClient() 

     With client 
      .Host = smtpHost 
     End With 

     Using message As New MailMessage(emailFrom, emailTo) 
      With message 
       .Subject = eSubject 
       .SubjectEncoding = Encoding.UTF8 
       .Body = eBody 
       .BodyEncoding = Encoding.UTF8 
       .IsBodyHtml = eBodyIsHtml 

       Select Case priority 
        Case 0 
         .Priority = MailPriority.Low 
        Case 1 
         .Priority = MailPriority.Normal 
        Case 2 
         .Priority = MailPriority.High 
       End Select 

       If eReplyTo.Length > 0 Then 
        Dim eReplyTos As String() = eReplyTo.Split(New Char() {","c}) 
        For i As Integer = 0 To eReplyTos.Length - 1 
         .ReplyToList.Add(eReplyTos(i).ToString) 
        Next 
       End If 

       If eCC.Length > 0 Then 
        Dim eCCs As String() = eCC.Split(New Char() {","c}) 
        For i As Integer = 0 To eCCs.Length - 1 
         .CC.Add(eCCs(i).ToString) 
        Next 
       End If 

       If eBCC.Length > 0 Then 
        Dim eBCCs As String() = eBCC.Split(New Char() {","c}) 
        For i As Integer = 0 To eBCCs.Length - 1 
         .Bcc.Add(eBCCs(i).ToString) 
        Next 
       End If 
      End With 

      AddHandler client.SendCompleted, AddressOf SendCompletedCallback 

      Dim userState As String = "Test" 
      client.SendAsync(message, userState) 
     End Using 
    Catch ex As Exception 
     mailError = "Execption Error: " & ex.Message 
     If Not ex.InnerException Is Nothing Then 
      mailError &= "<br /><br />" & ex.InnerException.ToString 
     End If 
    End Try 
End Sub 

Answer 1

Le moyen le plus rapide de mettre à jour l'interface utilisateur client (et puisque tous les codes à côté client, pas en service Web):

Private Sub SendCompletedCallback(ByVal sender As Object, ByVal e As AsyncCompletedEventArgs) 
Dim token As String = e.UserState.ToString() 

If Not e.Error Is Nothing Then 
    //SORRY, IN C# CODES 
    label.Text = token + " failed"; 
Else 
    //SORRY IN C# CODES 
    label.Text = token + " success"; 
End If 
End Sub 

Et le reste est à vous , c'est à dire. Gestionnaire d'événements label_text_change, vous voulez augmenter le messageBox, ou changer de couleur, vous pouvez également mettre label.visible = false, il suffit de l'utiliser pour déclencher/déclencher un gestionnaire d'événements.