title: Make a phonecall ios xamarin
body: <p>I currently have a button in a table view. I have a custom cell class and an update cell method.</p>
  
  <pre><code>public void UpdateCell (string subtitle2)
  {               
      call.SetTitle(subtitle2, UIControlState.Normal);
      call.TouchUpInside += (object sender, EventArgs e) =&gt; {
          UIApplication.SharedApplication.OpenUrl(new NSUrl("tel:" + subtitle2));
      };          
  }
  </code></pre>
  
  <p>However, when i run this segment of code, i get an error. </p>
  
  <blockquote>
    <p>Could not initialize an instance of the type
    'MonoTouch.Foundation.NSUrl': the native 'initWithString:' method
    returned nil. It is possible to ignore this condition by setting
    MonoTouch.ObjCRuntime.Class.ThrowOnInitFailure to false.</p>
  </blockquote>