C# 多个 http 请求相同的 PHP Z21D6F40CFB511982E442Z4E0E250A957

Question

我正在尝试将图片加载到将发送 POST 请求的同一 PHP session 中。 但是因为我使用的是 button1_Click 这是不可能的。 结果是在发送数据之前加载图片。 如果您有任何问题，请提出。

我知道我的 go 图片加载错误，但我不知道具体在哪里..

使用视觉 c# 2010 express winforms

private void Form1_Load(object sender, EventArgs e)
    {
        pictureBox1.ImageLocation = "http://localhost/proj/guess-my-fav/1.jpg";
    }
    private void button1_Click(object sender, EventArgs e)
    {
        Uri uri = new Uri("http://localhost/proj/guess-my-fav/level14.php");
        var answer = textBox1.Text;
        string data = "guess=" + answer + "&level=14&time=opt";
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
        request.Method = WebRequestMethods.Http.Post;
        request.CookieContainer = new CookieContainer();
        request.KeepAlive = true;
        request.ContentLength = data.Length;
        request.ContentType = "application/x-www-form-urlencoded";
        StreamWriter writer = new StreamWriter(request.GetRequestStream());
        writer.Write(data);
        writer.Close();
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        StreamReader reader = new StreamReader(response.GetResponseStream());
        string tmp = reader.ReadToEnd();
        response.Close();
        richTextBox1.AppendText(tmp); // log - delete this line          
    }

如何将图像渲染放在第二个请求下？

Answer 1

pictureBox1.ImageLocation = "http://localhost/proj/guess-my-fav/1.jpg";

这将导致客户端的浏览器请求1.jpg

Uri uri = new Uri("http://localhost/proj/guess-my-fav/level14.php");
...
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

这将导致运行 ASP.NET 网站的网络服务器请求level14.php

您不会使用相同的 session 收到这两个请求，因为它们将来自两台不同的机器！

您可能希望考虑将HttpWebRequest代码移出后端，并在客户端将其重新实现为 AJAX 请求。 那么这两个请求都将来自客户端的浏览器。

Answer 2

如果您修改代码以匹配

 private CookieContainer cookieContainer;

        private void Form1_Load(object sender, EventArgs e)
        {

            var wr = (HttpWebRequest)WebRequest.Create("http://localhost/proj/guess-my-fav/1.jpg");
            cookieContainer = new CookieContainer();
            wr.CookieContainer = this.cookieContainer;
            var resp = (HttpWebResponse)wr.GetResponse();
            wr.CookieContainer = cookieContainer;
            using (var s = resp.GetResponseStream())
            {
                pictureBox1.Image = new Bitmap(s);
            }
        }



private void button1_Click(object sender, EventArgs e)
    {
        Uri uri = new Uri("http://localhost/proj/guess-my-fav/level14.php");
        var answer = textBox1.Text;
        string data = "guess=" + answer + "&level=14&time=opt";
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
        request.Method = WebRequestMethods.Http.Post;
        request.CookieContainer = cookieContainer;
        request.KeepAlive = true;
        request.ContentLength = data.Length;
        request.ContentType = "application/x-www-form-urlencoded";
        StreamWriter writer = new StreamWriter(request.GetRequestStream());
        writer.Write(data);
        writer.Close();
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        StreamReader reader = new StreamReader(response.GetResponseStream());
        string tmp = reader.ReadToEnd();
        response.Close();
        richTextBox1.AppendText(tmp); // log - delete this line          
    }

这应该使用相同的 session 向服务器发出两个请求。

希望这可以帮助。

Answer 3

我在这里假设您想在单击按钮时重新加载图像。

首先， ImageLocation属性可能不会尊重您的 session cookie，因此您可能必须手动下载图像。 您已经使用了CookieContainer ，所以这是一个好的开始。

我们在这里要做的是使用一个新的HttpWebRequest下载图像并将相同的CookieContainer附加到它，因为在您第一次调用后，这个 CookieContainer 应该保存 session id。 然后我们可以使用HttpWebResponse创建一个Image object 并将其分配给pictureBox1.Image属性。

所有这一切可能看起来像这样：

private void button1_Click(object sender, EventArgs e)
{
    Uri uri = new Uri("http://localhost/proj/guess-my-fav/level14.php");
    var answer = textBox1.Text;
    string data = "guess=" + answer + "&level=14&time=opt";

    CookieContainer cookies = new CookieContainer(); /* we want to have this for other call also

    HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
    request.Method = WebRequestMethods.Http.Post;
    request.CookieContainer = cookies;
    request.KeepAlive = true;
    request.ContentLength = data.Length;
    request.ContentType = "application/x-www-form-urlencoded";
    StreamWriter writer = new StreamWriter(request.GetRequestStream());
    writer.Write(data);
    writer.Close();
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    StreamReader reader = new StreamReader(response.GetResponseStream());
    string tmp = reader.ReadToEnd();
    response.Close();
    richTextBox1.AppendText(tmp); // log - delete this line 

    HttpWebRequest request2 = (HttpWebRequest)HttpWebRequest.Create("http://localhost/proj/guess-my-fav/1.jpg");
    request2.CookieContainer = cookies;
    HttpWebResponse response2 = (HttpWebResponse)request.GetResponse();
    pictureBox1.Image = Image.LoadFromStream(response2.GetResponseStream());

}