/// <summary>
        /// Tries to match the selector with a control.
        /// </summary>
        /// <param name="control">The control.</param>
        /// <param name="subscribe">
        /// Whether the match should subscribe to changes in order to track the match over time,
        /// or simply return an immediate result.
        /// </param>
        /// <returns>A <see cref="SelectorMatch"/>.</returns>
        public SelectorMatch Match(IStyleable control, bool subscribe = true)
        {
            List <IObservable <bool> > inputs = new List <IObservable <bool> >();
            Selector selector = this;

            while (selector != null)
            {
                if (selector.InTemplate && control.TemplatedParent == null)
                {
                    return(SelectorMatch.False);
                }

                var match = selector.Evaluate(control, subscribe);

                if (match.ImmediateResult == false)
                {
                    return(match);
                }
                else if (match.ObservableResult != null)
                {
                    inputs.Add(match.ObservableResult);
                }

                selector = selector.MovePrevious();
            }

            if (inputs.Count > 0)
            {
                return(new SelectorMatch(StyleActivator.And(inputs)));
            }
            else
            {
                return(SelectorMatch.True);
            }
        }
Exemple #2
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        private static SelectorMatchResult Match(
            IStyleable control,
            Selector selector,
            IStyle?parent,
            bool subscribe,
            ref AndActivatorBuilder activators,
            ref Selector?combinator)
        {
            var previous = selector.MovePrevious();

            // Selectors are stored from right-to-left, so we recurse into the selector in order to
            // reverse this order, because the type selector will be on the left and is our best
            // opportunity to exit early.
            if (previous != null && !previous.IsCombinator)
            {
                var previousMatch = Match(control, previous, parent, subscribe, ref activators, ref combinator);

                if (previousMatch < SelectorMatchResult.Sometimes)
                {
                    return(previousMatch);
                }
            }

            // Match this selector.
            var match = selector.Evaluate(control, parent, subscribe);

            if (!match.IsMatch)
            {
                combinator = null;
                return(match.Result);
            }
            else if (match.Activator is object)
            {
                activators.Add(match.Activator !);
            }

            if (previous?.IsCombinator == true)
            {
                combinator = previous;
            }

            return(match.Result);
        }