title: Inject Default value for Web-Api Method parameter when its null
body: <p>i have a web api method something like;</p>
  
  <pre><code>[HttpGet, Route("users")]
  public HttpResponseMessage GetUsers([FromUri] UserSearchDto searchParams)
  {}
  </code></pre>
  
  <p>the searchParams is optional parameter so when i pass no search values and use simply like <a href="http://api-uri/users" rel="nofollow">http://api-uri/users</a> it becomes null and then i have to add check in the body of method to avoid null reference exception.</p>
  
  <p>is there a way using ActionFilters or something else to inject a default value for the parameter of this web api method so that i could avoid </p>
  
  <pre><code>if (searchParams == null){
    searchParams = new UserSearchDto ()
  }
  </code></pre>