vb.net - 无法在 vb.net 中发送超过一封邮件

Question

我正在尝试一次向多个人发送邮件。

我的代码是这样的；

 Dim SmtpServer As New SmtpClient()
            SmtpServer.Credentials = New Net.NetworkCredential("jasibs002@gmail.com", "someMadeUpPassword")
            SmtpServer.Port = 25
            SmtpServer.Host = "smtp.gmail.com"
            SmtpServer.EnableSsl = True
            Dim omail As New MailMessage()

        omail.From = New MailAddress("jasibs002@gmail.com", "JaseemBinBacker", System.Text.Encoding.UTF8)

        omail.Subject = "Test Mail"
        Dim str As String
        str = "Hai How Are You I am Sendig This Mail for Testing"
        str = str + vbNewLine & "Checking"
        str = str + vbNewLine & "Sucess"
        omail.Body = str
        Dim email As String
        Dim cmdemail As New SqlCommand("SELECT Emailid FROM  dbo.Email_tbl", con.connect)
        dr = cmdemail.ExecuteReader
        While dr.Read
            email = dr("Emailid")
            omail.To.Add(email)

        End While
        dr.Close()
        con.disconnect()
     SmtpServer.SendAsync(omail, Nothing)

    Catch ex As Exception
        MsgBox(ex.ToString)
    End Try

执行此操作时，出现以下错误； An asynchronous call is already in progress. It must be completed or canceled before you can call this method.

我的电子邮件Table有 10 多个电子邮件 ID。

Answer 1

将您的 While 循环更改为：

    While dr.Read
        email = dr("Emailid")
        omail.To.Add(email)

    End While
    SmtpServer.SendAsync(omail, Nothing)