how to display image directly from httpwebresponse stream in asp.net?

问题

I want to display image recieved from webresponse to browser directly without saving to a file.i have used below code to save the image to file but i want to display in browser directly.the website provides the captcha image in webresponse which i want to display.please help me.

public void captcha(string id, string pass)
{
    HttpWebRequest req;
    HttpWebResponse response;
    string strNewValue,ckuser,ckpass;
    System.Drawing.Image returnval;
    ckuser = id;
    ckpass = pass;
    this.req = (HttpWebRequest)WebRequest.Create("http://site2sms.com/security/captcha.asp");
    ServicePointManager.Expect100Continue = false;
    this.req.CookieContainer = new CookieContainer();
    this.req.AllowAutoRedirect = false;
    this.req.UserAgent = "Mozilla/5.0 (Windows NT 6.1; rv:8.0) Gecko/20100101 Firefox/8.0";
    this.req.Accept = "*/*";
    this.req.Method = "POST";
    this.req.CookieContainer = cookieCntr;
    this.req.ContentType = "application/x-www-form-urlencoded";
    this.req.Referer = "http://site2sms.com/verification.asp?source=login";
    this.strNewValue = "user=" + ckuser + "&password=" + ckpass + "&Submit=Sign+in";
    this.req.ContentLength = this.strNewValue.Length;
    StreamWriter writer = new StreamWriter(this.req.GetRequestStream(), Encoding.ASCII);
    writer.Write(this.strNewValue);
    writer.Close();
    this.response = (HttpWebResponse)this.req.GetResponse();
    returnval = Image.FromStream(response.GetResponseStream());
   // returnval.Save( Server.MapPath("captcha.bmp"));
    Response.AppendHeader("Content-Disposition:", "inline;filename=captcha.bmp");
    Response.ContentType = "image/bmp";
    Response.Write(returnval);
    Response.End();
    this.response.Close();
 }

回答1:

You can use HttpResponse.WriteFile method to send the stream to client directly. Writes the specified file directly to an HTTP response output stream.
You can create the IHttpHandler to send the stream, thus avoid some page life circle, increase the performance. Here is the link

来源：https://stackoverflow.com/questions/17780666/how-to-display-image-directly-from-httpwebresponse-stream-in-asp-net

标签

ASP.NET

httpwebresponse