undoabledelete.cs

c#精彩编程百例（源代码）

//  UndoableInsert.cs 
//  Copyright (c) 2000 Mike Krueger
//
//  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 2 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, write to the Free Software
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

using System;
using System.Diagnostics;
using System.Drawing;

using SharpDevelop.Internal.Text;

namespace SharpDevelop.Internal.Undo {
	
	/// <summary>
	/// This class is for the undo of TextBuffer delete operations
	/// </summary>
	class UndoableDelete : UndoableOperation
	{
		TextBuffer buffer;
		Point      from, to;
		string     text;
		
		public UndoableDelete(TextBuffer buffer, Point from, Point to, string text)
		{
			if (buffer == null)
				throw new ArgumentNullException("UndoableDelete(TextBuffer buffer, Point from, Point to, string text) : buffer can't be null");
			
			Debug.Assert(text != null, "SharpDevelop.Internal.Undo.UndoableDelete : text == null");
			
			this.buffer = buffer;
			this.from   = from;
			this.to     = to;
			this.text   = text;
		}
		
		public void Undo()
		{
			buffer._Insert(from, text);
		}
		
		public void Redo()
		{
			buffer._Delete(from, to);
		}
	}
}