Error “This stream does not support seek operations” in C#

Question

I\'m trying to get an image from an url using a byte stream. But i get this error message:

This stream does not support seek operations.<

Answer 1

You probably want something like this. Either checking the length fails, or the BinaryReader is doing seeks behind the scenes.

HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(url);
WebResponse myResp = myReq.GetResponse();

byte[] b = null;
using( Stream stream = myResp.GetResponseStream() )
using( MemoryStream ms = new MemoryStream() )
{
  int count = 0;
  do
  {
    byte[] buf = new byte[1024];
    count = stream.Read(buf, 0, 1024);
    ms.Write(buf, 0, count);
  } while(stream.CanRead && count > 0);
  b = ms.ToArray();
}

edit:

I checked using reflector, and it is the call to stream.Length that fails. GetResponseStream returns a ConnectStream, and the Length property on that class throws the exception that you saw. As other posters mentioned, you cannot reliably get the length of a HTTP response, so that makes sense.