context: //
  // System.Web.UI.WebControls.TreeNodeStyle.cs
  //
  // Authors:
  //	Lluis Sanchez Gual (lluis@novell.com)
  //
  // (C) 2004 Novell, Inc (http://www.novell.com)
  //
  // Permission is hereby granted, free of charge, to any person obtaining
  // a copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to
  // permit persons to whom the Software is furnished to do so, subject to
  // the following conditions:
  // 
  // The above copyright notice and this permission notice shall be
  // included in all copies or substantial portions of the Software.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  //
  // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  //
  
  
  using System;
  using System.Web.UI;
  using System.ComponentModel;
  
  namespace System.Web.UI.WebControls
  {
  	public sealed class TreeNodeStyle: Style
  	{
  		const string CHILD_PADD = "ChildNodesPadding";
  		const string HORZ_PADD = "HorizontalPadding";
  		const string IMG_URL = "ImageUrl";
  		const string SPACING = "NodeSpacing";
  		const string VERT_PADD = "VerticalPadding";
  
  		[Flags]
  		enum TreeNodeStyles
  		{
  			ChildNodesPadding = 0x00010000,
  			HorizontalPadding = 0x00020000,
  			ImageUrl = 0x00040000,
  			NodeSpacing = 0x00080000,
  			VerticalPadding = 0x00100000,
  		}
  		
  		public TreeNodeStyle ()
  			: base ()
  		{
  		}
  
  		public TreeNodeStyle (StateBag bag)
  			: base (bag)
  		{
  		}
  
  		[DefaultValue ("")]
  		[UrlProperty]
  		[NotifyParentProperty (true)]
  		[Editor ("System.Web.UI.Design.ImageUrlEditor, " + Consts.AssemblySystem_Design, typeof (System.Drawing.Design.UITypeEditor))]
  		public string ImageUrl {
  			get {
  				if (!CheckBit ((int) TreeNodeStyles.ImageUrl))
  					return String.Empty;
  				return ViewState.GetString (IMG_URL, String.Empty);
  			}
  			set {
  				if(value == null)
  					throw new ArgumentNullException("value");
  				ViewState [IMG_URL] = value;
  				SetBit ((int) TreeNodeStyles.ImageUrl);
  			}
  		}
  
  		[DefaultValue (0)]
  		[NotifyParentProperty (true)]
  		public Unit ChildNodesPadding {
  			get {
  				if (!CheckBit ((int) TreeNodeStyles.ChildNodesPadding))
  					return 0;
  				return ViewState [CHILD_PADD] == null ? 0 : (Unit) ViewState [CHILD_PADD];
  			}
  			set {
  				ViewState [CHILD_PADD] = value;
  				SetBit ((int) TreeNodeStyles.ChildNodesPadding);
  			}
  		}
  
  		[DefaultValue (0)]
  		[NotifyParentProperty (true)]
  		public Unit HorizontalPadding {
  			get {
  				if (!CheckBit ((int) TreeNodeStyles.HorizontalPadding))
  					return 0;
  				return ViewState [HORZ_PADD] == null ? 0 : (Unit) ViewState [HORZ_PADD];
  			}
  			set {
  				ViewState[HORZ_PADD] = value;
  				SetBit ((int) TreeNodeStyles.HorizontalPadding);
  			}
  		}
  
  		[DefaultValue (0)]
  		[NotifyParentProperty (true)]
  		public Unit VerticalPadding {
  			get {
  				if (!CheckBit ((int) TreeNodeStyles.VerticalPadding))
  					return 0;
  				return ViewState [VERT_PADD] == null ? 0 : (Unit) ViewState [VERT_PADD];
  			}
  			set {
  				ViewState [VERT_PADD] = value;
  				SetBit ((int) TreeNodeStyles.VerticalPadding);
  			}
  		}
  
  		[DefaultValue (0)]
  		[NotifyParentProperty (true)]
  		public Unit NodeSpacing {
  			get {
  				if (!CheckBit ((int) TreeNodeStyles.NodeSpacing))
  					return 0;
  				return ViewState [SPACING] == null ? 0 : (Unit) ViewState [SPACING];
  			}
  			set {
  				ViewState [SPACING] = value;
  				SetBit ((int) TreeNodeStyles.NodeSpacing);
  			}
  		}
  		
  		public override void CopyFrom (Style s)
  		{
  			if (s == null || s.IsEmpty)
  				return;
  
  			base.CopyFrom (s);
  			TreeNodeStyle from = s as TreeNodeStyle;
  			if (from == null)
  				return;
  
  			if (from.CheckBit ((int) TreeNodeStyles.ChildNodesPadding))
  				ChildNodesPadding = from.ChildNodesPadding;
  
  			if (from.CheckBit ((int) TreeNodeStyles.HorizontalPadding))
  				HorizontalPadding = from.HorizontalPadding;
  
  			if (from.CheckBit ((int) TreeNodeStyles.ImageUrl))
  				ImageUrl = from.ImageUrl;
  
  			if (from.CheckBit ((int) TreeNodeStyles.NodeSpacing))
  				NodeSpacing = from.NodeSpacing;
  
  			if (from.CheckBit ((int) TreeNodeStyles.VerticalPadding))
  				VerticalPadding = from.VerticalPadding;
  		}
  		
  		public override void MergeWith(Style s)
  		{
  			if(s != null && !s.IsEmpty)
  			{
  				if (IsEmpty) {
  					CopyFrom (s);
  					return;
  				}
  				base.MergeWith(s);
  
  				TreeNodeStyle with = s as TreeNodeStyle;
  				if (with == null) return;
  				
  				if (with.CheckBit ((int) TreeNodeStyles.ChildNodesPadding) && !CheckBit ((int) TreeNodeStyles.ChildNodesPadding)) {
  					ChildNodesPadding = with.ChildNodesPadding;
  				}
  				if (with.CheckBit ((int) TreeNodeStyles.HorizontalPadding) && !CheckBit ((int) TreeNodeStyles.HorizontalPadding)) {
  					HorizontalPadding = with.HorizontalPadding;
  				}
  				if (with.CheckBit ((int) TreeNodeStyles.ImageUrl) && !CheckBit ((int) TreeNodeStyles.ImageUrl)) {
  					ImageUrl = with.ImageUrl;
  				}
  				if (with.CheckBit ((int) TreeNodeStyles.NodeSpacing) && !CheckBit ((int) TreeNodeStyles.NodeSpacing)) {
  					NodeSpacing = with.NodeSpacing;
  				}
  				if (with.CheckBit ((int) TreeNodeStyles.VerticalPadding) && !CheckBit ((int) TreeNodeStyles.VerticalPadding)) {
  					VerticalPadding = with.VerticalPadding;
  				}
  			}
  		}
  
  		public override void Reset()
  		{
  			if (CheckBit ((int) TreeNodeStyles.ChildNodesPadding))
  				ViewState.Remove(CHILD_PADD);
  			if (CheckBit ((int) TreeNodeStyles.HorizontalPadding))
  				ViewState.Remove(HORZ_PADD);
  
gt: 			if (CheckBit ((int) TreeNodeStyles.ImageUrl))