asp.net - System.Net.Mail 新的 MailMessage 随机发送重复的电子邮件？

Question

我正在使用下面的代码来生成电子邮件。由于某种原因，它会随机发送重复的电子邮件。这种情况不会一直发生，每个月只会发生几次。您在我的代码中看到任何可能导致此问题的内容吗？当用户单击页面上的提交按钮时会触发它。我可以添加一些东西来防止这种情况发生吗？ TIA

Try
    Dim Attachment As String
    Attachment = path + myUniqueFileName

    Dim mailMessage As MailMessage = New MailMessage
    mailMessage.From = New MailAddress("Test@Test.com")
    mailMessage.Subject = "Report " + " " + myUniqueFileName
    mailMessage.IsBodyHtml = True
    mailMessage.To.Add(New MailAddress(Session("EmailAddress")))
    mailMessage.Attachments.Add(New Attachment(Attachment))
    mailMessage.Body = "Attached is your report"

    Dim smtp As SmtpClient = New SmtpClient

    smtp.Host = "mail.net"

    Dim NetworkCred As System.Net.NetworkCredential = New System.Net.NetworkCredential

    smtp.Credentials = New NetworkCredential("test", "test")
    smtp.UseDefaultCredentials = False
    smtp.Send(mailMessage)

Catch ex As Exception

    Dim message As String = ex.ToString
    Dim sb As New System.Text.StringBuilder()
    sb.Append("<script type = 'text/javascript'>")
    sb.Append("window.onload=function(){")
    sb.Append("alert('")
    sb.Append(message)
    sb.Append("\n")
    sb.Append(String.Format("{0:f2}", Convert.ToDouble(TotalAmount)))
    sb.Append("')};")
    sb.Append("</script>")
    ClientScript.RegisterClientScriptBlock(Me.GetType(), "alert", sb.ToString())

End Try

图像按钮代码:

 <asp:ImageButton ID="cmdFinish" runat="server" Height="38px" ImageUrl="~/Images/Finish.png" Width="99px" UseSubmitBehavior="false" OnClientClick="this.disabled = true; this.value = 'Sending...';" Text="Send" />

Answer 1

我以前遇到过同样的问题，所以我想我可以分享我的解决方案:

这是我的按钮标记代码，以避免再次重新单击它:

<asp:Button ID="btnSend" runat="server" CssClass="btn btn-primary" Width="150px" UseSubmitBehavior="false" OnClientClick="this.disabled = true; this.value = 'Sending...';" Text="Send" />

注意OnClientClick="this.disabled = true; this.value = '正在发送...'。

单击按钮后，它将禁用您的按钮并更改其文本。

另外，为了避免刷新页面时重新保存/重新提交/重新发送数据，我刚刚记忆了我的表单:

Response.Redirect("~/yourForm.aspx")