How to fill forms and submit with Webclient in C#

Question

Hey, I'm new at using the the libraries WebClient, HttpResponse and HttpRequest in C#, so bare over with me, if my question is confusing to read.

I need to build a WinForm based on C# which can open a URL, which is secured with the basic authorization. I did this with adding this to the header, like this:

        using (WebClient wc = new WebClient())
        {
           wc.Headers.Add(HttpRequestHeader.Authorization, "Basic " +
           Convert.ToBase64String(
           Encoding.ASCII.GetBytes(username + ":" + password)));
        }

So fare, so good! Now I would like to fill a form with a number, and I find the source-code from the site, and discover that the name is "number". So I write this:

         NameValueCollection formData = new NameValueCollection();  
         formData["number"] = number
         byte[] responseBytes = wc.UploadValues(theurl, "POST", formData);
         string response = Encoding.ASCII.GetString(responseBytes);
         textBox_HTML.Text = response;

But how do I submit this? I will like to receive my "result-search"...

Answer 1

You should probably be using HttpWebRequest for this. Here's a simple example:

var strId = UserId_TextBox.Text;
var strName = Name_TextBox.Text;

var encoding=new ASCIIEncoding();
var postData="userid="+strId;
postData += ("&username="+strName);
byte[]  data = encoding.GetBytes(postData);

var myRequest =
  (HttpWebRequest)WebRequest.Create("http://localhost/MyIdentity/Default.aspx");
myRequest.Method = "POST";
myRequest.ContentType="application/x-www-form-urlencoded";
myRequest.ContentLength = data.Length;
var newStream=myRequest.GetRequestStream();
newStream.Write(data,0,data.Length);
newStream.Close();

var response = myRequest.GetResponse();
var responseStream = response.GetResponseStream();
var responseReader = new StreamReader(responseStream);
var result = responseReader.ReadToEnd();

Answer 2

You submitted it already with UploadValues. The question is: what is your "result-search"? What does the page return? HTML? If so - the HTML Agility Pack is the easiest way to parse html.

Answer 3

I have found a solution to my problem. First of all I was confused about some of the basics in http-communication. This was caused by a python-script i wrote, which have a different approach with the communication.

I solved it with generating the POST-data from scratch and open the uri, which was contained in the form-action.