Question

我正在使用SMTP服务器发送电子邮件。我想在SMTP服务器关闭或电子邮件未送达时收到错误消息使用DeliveryNotificationOptions.OnFailure，我收到一封电子邮件，表明该电子邮件尚未发送我想得到一个错误。这可能吗？
我如何检查SMTP是否正在运行？

以下是我使用的代码：

Dim serverName As String = ""
Dim mailSenderInstance As SmtpClient = Nothing
Dim AnEmailMessage As New MailMessage
Dim sendersEmail As String = ""
Try
    serverName = GetServerName("EMAIL_SERVER")
    mailSenderInstance = New SmtpClient(serverName, 25)
    sendersEmail = GetSendersEmail(msUserName)
    AnEmailMessage.From = New MailAddress(sendersEmail)

   'MAIL DETAILS
    AnEmailMessage.Subject = "New Email"
    AnEmailMessage.Body = "The Message"
    AnEmailMessage.To.Add(anEmailAddress)

    ' Delivery notifications
    AnEmailMessage.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure
    mailSenderInstance.UseDefaultCredentials = True 'False
    mailSenderInstance.Send(AnEmailMessage)

Catch ex As System.Exception
    MessageBox.Show(ex.ToString)
Finally
    AnEmailMessage.Dispose()
    mailSenderInstance.Dispose() 
End Try

Answer 1

在SMTP声明周围添加另一个try catch块

try
   mailSenderInstance = New SmtpClient(serverName, 25)
catch ex as exception
    msgbox( "Error creating SMTP connection: " & ex.message)
end try

问候

Answer 2

好的，您想知道SMTP状态。 SMTP作为服务运行。我已经为您编写了一个函数来了解系统中任何服务的状态。在项目中添加对“System.ServiceProcess”的引用。

''response: -1 = service missing, 0 = stopped or stopping, 1 = running

imports System.ServiceProcess ''add this at top 

Private Function GetServiceStatus(ByVal svcName As String) As Integer  
    Dim retVal As Integer
    Dim sc As New ServiceController(svcName)
    Try
        If sc.Status.Equals(ServiceControllerStatus.Stopped) Or sc.Status.Equals(ServiceControllerStatus.StopPending) Then
            retVal = 0
        Else
            retVal = 1
        End If
    Catch ex As Exception
        retVal = -1
    End Try
    Return retVal
End Function

像这样使用它：

'' use taskManager to figure correct service name
dim svStatus as integer = GetServiceStatus("SMTP") 
if svStatus <> 1 then 
  msgbox("Service not running or absent")
else
  ''write your send mail code here
end if

希望这会对你有所帮助

检查SMTP是否正在运行或发送电子邮件失败

2 个答案: