title: How to check a string is html encoded or not?
body: <p>I am working with my web API. Some user send parameter string as HTML encoded I want to identify the coming parameters are HTML encoded or plain text.</p>
  
  <p>My Web API method is </p>
  
  <pre><code>public HttpResponseMessage Get(string Accesskey, string AccessPwd)
  {
     // code logic
  }
  </code></pre>
  
  <p>i am getting Accesskey as Html Encoded like </p>
  
  <pre><code>Accesskey="AbIfZVn4y514sJbt%2BCCMJy6lsmsMi6uOWyhUhynDSf1MEqZ%2FWJnwUuCFO8zMFa4jCRWQrXHKdBaHd9CCdDNfoKDnPg1W9No16JQbL2DBEGg%3D";
  </code></pre>
  
  <p>i want output like </p>
  
  <pre><code>Accesskey="AbIfZVn4y514sJbt+CCMJy6lsmsMi6uOWyhUhynDSf1MEqZ/WJnwUuCFO8zMFa4jCRWQrXHKdBaHd9CCdDNfoKDnPg1W9No16JQbL2DBEGg="
  </code></pre>