Question

我搜索了很多文章并找到了一些代码，但它对我不起作用。

我的index.aspx.cs页面代码是：

 protected void Page_Load(object sender, EventArgs e)
 {
    if (checkIfRequested(this.Context.Request))
    {           
        //receiver had already requested the image, hence send back a not modified result
        Response.StatusCode = 304;
        Response.SuppressContent = true;
    }
    else
    {
        int emailId = 0;
        if (!string.IsNullOrEmpty(Request.QueryString["emailId"]) && int.TryParse(Request.QueryString["emailId"], out emailId))
        {
            Session["image"] = Request.QueryString["emailId"];
            lblid.Text = Convert.ToString(Session["image"]);


            //The email with emailId has been opened, so log that in database
        }
        else
        {
            if (Request.QueryString["emailId"] != null)
            {
                lblid.Text = Convert.ToString(Request.QueryString["emailId"]);
            }
            string str = "<script>alert('empty')</script>";
            Page.RegisterStartupScript("popup", str);
        }

        //Send the single pixel gif image as response
        byte[] imgbytes = Convert.FromBase64String("R0lGODlhAQABAIAAANvf7wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==");
        Response.ContentType = "image/gif";
        Response.AppendHeader("Content-Length", imgbytes.Length.ToString());
        Response.Cache.SetLastModified(DateTime.Now);
        Response.Cache.SetCacheability(HttpCacheability.Public);
        Response.BinaryWrite(imgbytes);
    }
}

private bool checkIfRequested(HttpRequest req)
{
    // check if-modified-since header to check if receiver has already requested the image in last 24 hours
    return req.Headers["If-Modified-Since"] == null ? false : DateTime.Parse(req.Headers["If-Modified-Since"]).AddHours(24) >= DateTime.Now;
}

我的index.aspx页面似乎如下：

<body>
<form id="form1" runat="server">
<asp:Label ID="lblid" runat="server" Text=""></asp:Label>   
</form>
</body>

我曾经从我的aspx页面发送电子邮件到我自己的Gmail ID，如：

String MailContent = "";
MailContent += "<img src='http://WWW.mywebsitename.com/index.aspx?emailId=1' width='1' height='1' />
client = new SmtpClient();
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("Myemailidofhmail", "mypassword");
client.Port = 25;
client.Host = "smtp.gmail.com";
client.EnableSsl = true; 
mailto = "mitesh@gmail.com";
message = MailContent.ToString();
msg = new System.Net.Mail.MailMessage();
msg.To.Add(mailto);

此处邮件已成功发送到mitesh@gmail.com个ID上的我的Gmail帐户，但是当我从我的帐户中打开该电子邮件时，我的Request.QueryString["emailId"] <1的值不是index.aspx / p>

Answer 1

请参阅这些问题的答案：

Is there any way to track whether an email has been opened?

Mass email tracking

引用第一个问题的答案：

邮件客户端阻止了所有这些尝试。该最好的想法是给他们一个他们希望看到的图像阅读消息，因此他们选择在他们的图像中显示图像邮件客户端。

所以，是的，这几乎是最好的建议，即使这样，如果电子邮件客户端缓存你的图像它可能也不会很好（尽管它应该仍然可以记录第一次下载）。没有万无一失的方法来实际验证某人是否阅读了您的电子邮件，除非您可以通过电子邮件中的链接访问您的网站。

跟踪是否读取已发送的邮件

1 个答案: