title: Unable to get request header in asp net core web API
body: <p>I am trying to create a custom filter in asp net core web api which is as below but unable to get header info.</p>
  
  <pre><code>internal class BasicAuthFilterAttribute : ActionFilterAttribute
  {
    private StringValues xyz;
  
    public override void OnActionExecuting(ActionExecutingContext actionContext)
    {
      var authHeader = actionContext.HttpContext.Request.Headers.TryGetValue("Basic", out xyz);           
    }
  }
  </code></pre>
  
  <p><code>TryGetValue</code> always return false however I can see <code>Headers</code> contains the "Basic" header. As I am new in ASP.NET Core so can anyone guide me what I am possibly doing wrong?  </p>
  
  <p>Here how headers looks like.
  <a href="https://i.stack.imgur.com/13PIi.png" rel="noreferrer"><img src="https://i.stack.imgur.com/13PIi.png" alt="enter image description here"></a></p>