Vb.net 检查SMTP是否正在运行或发送电子邮件失败

我正在使用SMTP服务器发送电子邮件。 我希望在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，表示该电子邮件尚未送达。
我想得到一个错误。这可能吗？
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

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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

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关于

好的，您想知道SMTP状态。SMTP作为服务运行。我编写了一个函数，让您了解系统中任何服务的状态。将对“System.ServiceProcess”的引用添加到项目中

''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

''使用taskManager计算正确的服务名称
dim svStatus as integer=GetServiceStatus（“SMTP”）
如果状态为1，则
msgbox（“服务未运行或不存在”）
其他的
''在这里写下你的发送邮件代码
如果结束

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希望这对你有帮助

这有什么帮助？当服务器不运行时，它不会给我一个错误或一个小问题。我找不到任何与SMTP相关的服务？我使用的是windows 2007。您使用的是哪台web服务器？Exchange server正在另一台计算机上运行，我的计算机上有outlook