Question

我在asp.net和C＃中有一个带提交按钮的表单。表单用于通过电子邮件向网站站长提交评论。 C＃代码如下。

但面临一个问题。即刷新页面时，由于回发，它再次在电子邮件中发送评论。我怎么能避免这个？这是代码......

protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void btnSubmit_Click(object sender, EventArgs e)
    {

            string body = "";
            //body = body + "<html><head></head><body>";

            body = body + "Dear Balvignan Team,\r\n";

            if (txtComment.Text != null)
            {
                body = body + "Comment: " + txtComment.Text;
            }



            if (SendEmail(txtEmail.Text.Trim(), "Comment", body, false) == true)
            {

                lblContactAcknowledge.Text = "Thank You For <br />Submitting comment.";

                lblContactAcknowledge.Visible = true;
                PnlTalkToUs.Visible = false;
            }
            else
            {
                lblContactAcknowledge.Visible = false;
                PnlTalkToUs.Visible = true;
            }

    }

SendEmail是发送电子邮件的功能。

Answer 1

在您的page_load活动中

if(page.isPostback==NO)
{
    //send an email
}
else
{
   //Don't send
}

Answer 2

您可以使用Page.IsPostBack Property检查是否为回发或页面刷新。

Answer 3

您可以使用以下选项：

  if (SendEmail(txtEmail.Text.Trim(), "Comment", body, false) == true)
            {
               Response.Redirect("contact.aspx?success=true");
             }
          else
          {
              Response.Redirect("contact.aspx");
          }

页面加载

if (!Page.IsPostback)
{
   if (Request.QueryString["success"] == "true" )
   {
      lblContactAcknowledge.Text = "Thank You For <br />Submitting comment.";

      lblContactAcknowledge.Visible = true;
      PnlTalkToUs.Visible = false;
   }
   else
   {
      lblContactAcknowledge.Visible = false;
      PnlTalkToUs.Visible = true;
   }
}

当用户刷新页面（ctrl + r，f5等）将发送给GET请求，而不是POST请求。

编辑其他解决方案

另一种解决方案是使用ViewState：

 public bool EmailSent
        {
            get
            {
                return ViewState["EmailSent"] != null ? (bool)ViewState["EmailSent"] : false;
            }
            set
            {
                ViewState["EmailSent"] = value;
            }
        }


protected void btnSubmit_Click(object sender, EventArgs e)
{
        ....
        if (!EmailSent)
        {

           if (SendEmail(txtEmail.Text.Trim(), "Comment", body, false) == true)
           {       
              ... 
              EmailSent = true;
           }
           else
           {
              ...
           }
        }
}

表格回复相关

3 个答案: