Test Execute fails in mapping GUI object

Hi, there is no error , just exit after timeout.

 public var WaitObject(var rootNode, string stringExp, double timeOutMilliSeconds)
        {
            var obj;
            DateTime startTime = DateTime.Now;

            obj = FindChild(rootNode, stringExp, "");
            if (obj != null)
            {
                return obj;
            }

            while (timeOutMilliSeconds > ((int) (DateTime.Now - startTime).TotalMilliseconds))
            {
                obj = FindChild(rootNode, stringExp, "");
                if (obj != null)
                {
                    return obj;
                }

                Thread.Sleep(50);
            }

            return null;
        }