Xamarin.Forms.Xaml/RegisterXNamesVisitor.cs


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using System;
using System.Collections.Generic;

namespace Xamarin.Forms.Xaml
{
	internal class RegisterXNamesVisitor : IXamlNodeVisitor
	{
		public RegisterXNamesVisitor(HydratationContext context)
		{
			Values = context.Values;
		}

		Dictionary<INode, object> Values { get; }

		public bool VisitChildrenFirst
		{
			get { return false; }
		}

		public bool StopOnDataTemplate
		{
			get { return true; }
		}

		public bool StopOnResourceDictionary
		{
			get { return false; }
		}

		public void Visit(ValueNode node, INode parentNode)
		{
			if (!IsXNameProperty(node, parentNode))
				return;
			try
			{
				((IElementNode)parentNode).Namescope.RegisterName((string)node.Value, Values[parentNode]);
			}
			catch (ArgumentException ae)
			{
				if (ae.ParamName != "name")
					throw ae;
				throw new XamlParseException(
					string.Format("An element with the name \"{0}\" already exists in this NameScope", (string)node.Value), node);
			}
		}

		public void Visit(MarkupNode node, INode parentNode)
		{
		}

		public void Visit(ElementNode node, INode parentNode)
		{
		}

		public void Visit(RootNode node, INode parentNode)
		{
		}

		public void Visit(ListNode node, INode parentNode)
		{
		}

		static bool IsXNameProperty(ValueNode node, INode parentNode)
		{
			var parentElement = parentNode as IElementNode;
			INode xNameNode;
			if (parentElement != null && parentElement.Properties.TryGetValue(XmlName.xName, out xNameNode) && xNameNode == node)
				return true;
			return false;
		}
	}
}