How to submit http form using C#

Question

I have a simple html file such as

<form action="http://www.someurl.com/page.php" method="POST">    <input type="text" name="test"><br/>    <input type="submit" name="submit"> </form> 

Edit: I may not have been clear enough with the question

I want to write C# code which submits this form in the exact same manner that would occur had I pasted the above html into a file, opened it with IE and submitted it with the browser.

Answer 1

Here is a sample script that I recently used in a Gateway POST transaction that receives a GET response. Are you using this in a custom C# form? Whatever your purpose, just replace the String fields (username, password, etc.) with the parameters from your form.

private String readHtmlPage(string url)    {      //setup some variables      String username  = "demo";     String password  = "password";     String firstname = "John";     String lastname  = "Smith";      //setup some variables end        String result = "";       String strPost = "username="+username+"&password="+password+"&firstname="+firstname+"&lastname="+lastname;       StreamWriter myWriter = null;        HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);       objRequest.Method = "POST";       objRequest.ContentLength = strPost.Length;       objRequest.ContentType = "application/x-www-form-urlencoded";        try       {          myWriter = new StreamWriter(objRequest.GetRequestStream());          myWriter.Write(strPost);       }       catch (Exception e)        {          return e.Message;       }       finally {          myWriter.Close();       }        HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();       using (StreamReader sr =           new StreamReader(objResponse.GetResponseStream()) )       {          result = sr.ReadToEnd();           // Close and clean up the StreamReader          sr.Close();       }       return result;    }  

Answer 2

Your HTML file is not going to interact with C# directly, but you can write some C# to behave as if it were the HTML file.

For example: there is a class called System.Net.WebClient with simple methods:

using System.Net; using System.Collections.Specialized;  ... using(WebClient client = new WebClient()) {      NameValueCollection vals = new NameValueCollection();     vals.Add("test", "test string");     client.UploadValues("http://www.someurl.com/page.php", vals); } 

For more documentation and features, refer to the MSDN page.