如何使用我的 vb.net 代码发送电子邮件？

Question

我正在使用 asp.net / vb.net。我想发一封电子邮件。我的代码没有按原样发送电子邮件。我想知道我在这里做错了什么。

我创建了一个名为 email.text 的文件，其中包含电子邮件模板。发送电子邮件的其余代码如下。我从代码中删除了个人信息。

我这样设置 SMTP 连接：

Private SMTPClientConnection As SmtpClient
Sub New()
    SMTPClientConnection = New SmtpClient
    SMTPClientConnection.Host = "HOSTHERE"
    SMTPClientConnection.Port = PORTHERE
    SMTPClientConnection.DeliveryMethod = SmtpDeliveryMethod.Network
End Sub

然后我创建了一个发送电子邮件的函数：

Private Shared Function SendEmail(ByVal emailUser As String, ByVal bodyMessage As List(Of String), ByVal priority As MailPriority) As Boolean
    Dim functionReturnValue As Boolean = False

    Try

        If Not String.IsNullOrWhiteSpace(emailUser) Then

            If Regex.IsMatch(emailUser, "^([a-zA-Z0-9]+([\.+_-][a-zA-Z0-9]+)*)@(([a-zA-Z0-9]+((\.|[-]{1,2})[a-zA-Z0-9]+)*)\.[a-zA-Z]{2,6})$") Then

                Using SMTPClientConnection
                    Dim smtpMessage As MailMessage = New MailMessage()
                    Dim _with1 = smtpMessage
                    _with1.[To].Add(New MailAddress(emailUser))
                    _with1.From = New MailAddress("Test Email" & " <email@email.com>")
                    _with1.ReplyToList.Add(New MailAddress("email@email.com"))
                    _with1.Subject = "Test Email"
                    _with1.Priority = priority
                    Dim htmlView As AlternateView = AlternateView.CreateAlternateViewFromString(bodyMessage(0), Nothing, "text/html")
                    Dim plainView As AlternateView = AlternateView.CreateAlternateViewFromString(bodyMessage(1), Nothing, "text/plain")
                    _with1.AlternateViews.Add(plainView)
                    _with1.AlternateViews.Add(htmlView)
                    SMTPClientConnection.Send(smtpMessage)
                    Return True
                End Using
            Else
                Throw New SmtpException("Invalid email.")
            End If
        End If

    Catch ex As Exception
    End Try

    Return functionReturnValue
End Function

我在这里的代码中使用了这个函数：

            Dim plainBody As String = File.ReadAllText(HttpContext.Current.Server.MapPath("email.txt"))
            plainBody = plainBody.Replace("%Name%", emailName)

            Dim emailBody As List(Of String) = New List(Of String)(New String() {plainBody})
            SendEmail("email@email.com", emailBody, MailPriority.Normal)

Answer 1

编译器错误信息很清楚。变量 SmtpClientConnection 是一个实例变量（它作为不同的实体存在于任何声明的类实例中）但您试图在 Shared 方法中使用（该方法存在没有类实例）。在这种方法中你不能使用实例变量，因为你没有一个实例可以让方法从中选择变量值并使用它。

解决方案可能是从方法中删除 Shared 关键字，然后，每当您要调用该方法时，您需要创建实例变量 SmtpClientConnection 已初始化并准备好在以下对 SendMail 方法的调用中使用。

但是，您仍然可以使用 Shared 方法，但应该删除实例变量并在 SmtpClient 方法中创建它：

Private Shared Function SendEmail(ByVal emailUser As String, ByVal bodyMessage As List(Of String), ByVal priority As MailPriority) As Boolean
    Dim functionReturnValue As Boolean = False

    Try

        If Not String.IsNullOrWhiteSpace(emailUser) Then

            If Regex.IsMatch(emailUser, "^([a-zA-Z0-9]+([\.+_-][a-zA-Z0-9]+)*)@(([a-zA-Z0-9]+((\.|[-]{1,2})[a-zA-Z0-9]+)*)\.[a-zA-Z]{2,6})$") Then


               Dim SMTPClientConnection As SmtpClient = New SmtpClient
               SMTPClientConnection.Host = "HOSTHERE"
               SMTPClientConnection.Port = PORTHERE
               SMTPClientConnection.DeliveryMethod = SmtpDeliveryMethod.Network                
               Using SMTPClientConnection
                    Dim smtpMessage As MailMessage = New MailMessage()
                    ......
                    SMTPClientConnection.Send(smtpMessage)
                    Return True
                End Using
            Else
                Throw New SmtpException("Invalid email.")
            End If
        End If

    Catch ex As Exception
       ' No point in catching an exception and doing nothing here.
       ' You can log the exception somewhere and then throw it again
       LogException(ex)
       Throw
       ' or just remove the try/catch block.
    End Try
    Return functionReturnValue
End Function

通过这种方式，变量仅在需要时创建，并在 using 语句结束时销毁。还要注意与 Try/Catch 块相关的 cmets。