How can I write an XML on my hard drive to GetRequestStream

I need to post raw xml to a site and read the response. With the following code I keep getting an "Unknown File Format" error and I'm not sure why.

            XmlDocument sampleRequest = new XmlDocument();
            sampleRequest.Load(@"C:\SampleRequest.xml");
            byte[] bytes = Encoding.UTF8.GetBytes(sampleRequest.ToString());

            string uri = "https://www.sample-gateway.com/gw.aspx";
            req = WebRequest.Create(uri);
            req.Method = "POST";
            req.ContentLength = bytes.Length;
            req.ContentType = "text/xml";

            using (var requestStream = req.GetRequestStream())
            {
                requestStream.Write(bytes, 0, bytes.Length);
            }

            // Send the data to the webserver
            rsp = req.GetResponse();

            XmlDocument responseXML = new XmlDocument();
            using (var responseStream = rsp.GetResponseStream())
            {
                responseXML.Load(responseStream);
            }

I am fairly cert开发者_C百科ain my issue is what/how I am writing to the requestStream so..

How can I modify that code so that I may write an xml located on the hard drive to the request stream?

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ok instead of doing sampleRequest.ToString(), you should use sampleRequest.OuterXml, and that would do the magic, you were sending "System.Xml.XmlDocument" instead of the Xml

    XmlDocument sampleRequest = new XmlDocument();
    sampleRequest.Load(@"C:\SampleRequest.xml");
    //byte[] bytes = Encoding.UTF8.GetBytes(sampleRequest.ToString());
    byte[] bytes = Encoding.UTF8.GetBytes(sampleRequest.OuterXml);

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Two things:

First, whenever you're trying to diagnose a problem with an HTML response, you should always examine what the response stream actually contains. If you had in this case, you would have seen that it contains System.Xml.XmlDocument, which would have told you what was wrong pretty much immediately.

Second, in an application with any kind of transaction volume, you're not going to want to load a static XML file into an XmlDocument before putting it in the response stream; your program's spending time and memory building something that you don't need. (It's even worse than that in your case; your approach not only parses the XML into a DOM object, it then makes an in-memory copy of its OuterXml property when you encode it as UTF-8. Also, do you really need to be doing that?) Instead, you should create a FileStream object and use one of the techniques in this answer to copy it to the response stream.