undocomd.cs

Csharp设计模式一书的源码

using System;
using System.Drawing ;
using System.Windows.Forms;
using System.Collections ;

namespace UndoCommand
{
	/// <summary>
	/// Summary description for UndoCommand.
	/// </summary>
	public class UndoComd:Command 	{
		private ArrayList undoList;
		public UndoComd() 	{
			undoList = new ArrayList ();
		}
		//-----
		public void add(Command comd) {
			if(! comd.isUndo ()) {
				undoList.Add (comd);
			}
		}
		//-----
		public bool isUndo() {
			return true;
		}
		//-----
		public void Undo() {		}
		//-----
		public void Execute() {
			int index = undoList.Count - 1;
			if (index >= 0) {
				Command cmd = (Command)undoList[index];
				cmd.Undo();
				undoList.RemoveAt(index);
			}
		}
	}
}