title: Send POST request to asp.net mvc action via Fiddler
body: <p>I have an <code>ASP.NET MVC</code> web site. One of my routes is a <code>URL</code> that takes 5 parameters. For the sake of illustration, these parameters are named <code>parameter1</code>, <code>parameter2</code>, <code>parameter3</code>, <code>parameter4</code>, and <code>parameter5</code>. Currently, I'm constructing a URL in some <code>C#</code> code that will <code>POST</code> to the mvc action via a <code>WebClient</code>. that code looks like this:</p>
  
  <pre><code>WebClient myWebClient = new WebClient();
  myWebClient.UploadStringCompleted += myWebClient_UploadStringCompleted;
  
  string url = "http://www.example.com/customer/" + parameter1 + "/orders/" + parameter2 + "/" + parameter3 + "/" + parameter4 + "/" + parameter5;
  myWebClient.UploadStringAsync(new Uri(url, UriKind.Absolute));
  </code></pre>
  
  <p>I'm confident that the <code>UploadString</code> method does a <code>POST</code>. I need to do a <code>POST</code>, because my parameter values can be very long. In fact, I estimate that occasionally, the total url length may be 20000 characters long. Regardless, I get a <code>400 error</code> when I attempt to post my data. In an effort to debug this, I'm  trying to figure out how to simulate a <code>POST</code> in <code>Fiddler</code>. </p>
  
  <p>Assuming that I am passing values via a query string as shown above, what values do I enter into <code>Fiddler</code>? From the <code>Composer</code> tab, I'm not sure what to enter for the <code>Request Headers</code> area. I'm also not entirely sure what to enter for the url. I'm not sure if I put the entire URL in there, including the parameter values, or if those belong in the <code>Request Headers</code>.</p>
  
  <p>What I need to enter into <code>Fiddler</code>, so that I can debug my issue?</p>