greenshot/Greenshot/Drawing/Fields/AbstractFieldHolderWithChildren.cs

/*
 * Greenshot - a free and open source screenshot tool
 * Copyright (C) 2007-2016 Thomas Braun, Jens Klingen, Robin Krom
 * 
 * For more information see: http://getgreenshot.org/
 * The Greenshot project is hosted on GitHub https://github.com/greenshot/greenshot
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 1 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

using GreenshotPlugin.Interfaces.Drawing;
using System;
using System.Collections.Generic;
using System.Runtime.Serialization;

namespace Greenshot.Drawing.Fields
{
	/// <summary>
	/// Basic IFieldHolderWithChildren implementation. Similar to IFieldHolder,
	/// but has a List of IFieldHolder for children.
	/// Field values are passed to and from children as well.
	/// </summary>
	[Serializable]
	public abstract class AbstractFieldHolderWithChildren : AbstractFieldHolder
	{
		[NonSerialized]
		private readonly FieldChangedEventHandler _fieldChangedEventHandler;

		[NonSerialized]
		private EventHandler childrenChanged;
		public event EventHandler ChildrenChanged
		{
			add { childrenChanged += value; }
			remove { childrenChanged -= value; }
		}

		public List<IFieldHolder> Children = new List<IFieldHolder>();

		public AbstractFieldHolderWithChildren()
		{
			_fieldChangedEventHandler = OnFieldChanged;
		}

		[OnDeserialized()]
		private void OnDeserialized(StreamingContext context)
		{
			// listen to changing properties
			foreach (IFieldHolder fieldHolder in Children)
			{
				fieldHolder.FieldChanged += _fieldChangedEventHandler;
			}
			childrenChanged?.Invoke(this, EventArgs.Empty);
		}

		public void AddChild(IFieldHolder fieldHolder)
		{
			Children.Add(fieldHolder);
			fieldHolder.FieldChanged += _fieldChangedEventHandler;
			childrenChanged?.Invoke(this, EventArgs.Empty);
		}

		public void RemoveChild(IFieldHolder fieldHolder)
		{
			Children.Remove(fieldHolder);
			fieldHolder.FieldChanged -= _fieldChangedEventHandler;
			childrenChanged?.Invoke(this, EventArgs.Empty);
		}

		public new IList<IField> GetFields()
		{
			var ret = new List<IField>();
			ret.AddRange(base.GetFields());
			foreach (IFieldHolder fh in Children)
			{
				ret.AddRange(fh.GetFields());
			}
			return ret;
		}

		public new IField GetField(IFieldType fieldType)
		{
			IField ret = null;
			if (base.HasField(fieldType))
			{
				ret = base.GetField(fieldType);
			}
			else
			{
				foreach (IFieldHolder fh in Children)
				{
					if (fh.HasField(fieldType))
					{
						ret = fh.GetField(fieldType);
						break;
					}
				}
			}
			if (ret == null)
			{
				throw new ArgumentException("Field '" + fieldType + "' does not exist in " + GetType());
			}
			return ret;
		}

		public new bool HasField(IFieldType fieldType)
		{
			bool ret = base.HasField(fieldType);
			if (!ret)
			{
				foreach (IFieldHolder fh in Children)
				{
					if (fh.HasField(fieldType))
					{
						ret = true;
						break;
					}
				}
			}
			return ret;
		}

		public new bool HasFieldValue(IFieldType fieldType)
		{
			IField f = GetField(fieldType);
			return f != null && f.HasValue;
		}

		public new void SetFieldValue(IFieldType fieldType, object value)
		{
			IField f = GetField(fieldType);
			if (f != null) f.Value = value;
		}

	}
}