Retrieve image from an aspx URL

Question

I am trying to get my Visual C# program to download an image from a URL that ends in .aspx. This image is actually a captcha code, and it changes with time.

What I have tried to do thus far is create a PictureBox, and I have set the ImageLocation to the ASPX url that returns an image.

However, this gives me nothing but a red boxed X where the captcha image should have appeared.

Is there some code I should type? Sorry for my lack of understanding, I'm a newbie at this C# business!

Thanks for all your help!

Answer 1

You can try downloading the image manually to see if you get a valid image

using (WebClient webclient = new WebClient())
{
    using (var imageStream = webclient.OpenRead("http://example.com/image.png"))
    {
        Image img = Image.FromStream(imageStream);                   
    }
}

If you don't get a valid image, you can then try var str = webclient.DownloadString("http://example.com/image.png"); and inspect the str variable to see if you get some error text data from the webserver instead of an image.

Answer 2

Thanks to everybody who has helped out in answering this question!

I was dealing with a rather picky server which would only allow clients with a valid user-agent to access the site it was hosting. Adding:

webclient.Headers["User-Agent"] = "Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.0; SV1; .NET CLR 3.0.4506.2152; .NET CLR 3.0.30618)2011-09-18 00:09:44";

solved the problem.

Thanks!