source: trunk/sources/HeuristicLab.ExtLibs/HeuristicLab.Netron/3.0.2672.12446/Netron.Diagramming.Core-3.0.2672.12446/UndoRedo/Command.cs @ 2768

using System;

namespace Netron.Diagramming.Core
{
    /// <summary>
    /// Command is an abstract class that represents an undoable
    /// or redoable operation or command. It provides virtual Undo()
    /// and Redo() methods which your derived command classes can
    /// override in order to implement actual undo/redo functionality.
    /// In a derived command class, you also have the option of
    /// not overriding the Undo() and Redo() methods. Instead, you
    /// can treat the derived command class like a data class and
    /// simply provide extra fields, properties, or methods that an
    /// external class (one that implements IUndoHandler) can use to
    /// perform the actual undo/redo functionality.
    /// </summary>
    public abstract class Command : ICommand
    {

        #region Fields
        /// <summary>
        /// the Controller field
        /// </summary>
        private IController mController;

        /// <summary>
        /// the description of the action
        /// </summary>
        private string mText = string.Empty;
        #endregion

        #region Properties
        /// <summary>
        /// Gets or sets the Controller
        /// </summary>
        protected IController Controller
        {
            get { return mController; }
            set { mController = value; }
        }
        /// <summary>
        /// Text should return a short description of the
        /// user operation associated with this command. For example,
        /// a graphics line drawing operation might have the
        /// text, "Draw Line". This method can be used to update
        /// the Text property of an undo menu item. For example,
        /// instead of just displaying "Undo", the Text property
        /// of an undo menu item can be augmented to "Undo Draw Line".
        /// </summary>
        /// <returns>Short description of the command.</returns>
        public virtual string Text
        {
            get
            {
                return mText;
            }
            set
            {
                mText = value;
            }
        }
        #endregion

        #region Constructor
        /// <summary>
        /// Default constructor
        /// </summary>
        /// <param name="controller">The controller.</param>
        protected Command(IController controller)
        {
            if (controller == null)
                throw new InconsistencyException("The controller is 'null'");
            this.mController = controller;
        }
        #endregion

        #region Methods
        /// <summary>
        /// Perform undo of this command.
        /// </summary>
        public virtual void Undo()
        {
            // Empty implementation.
        }

        /// <summary>
        /// Perform redo of this command.
        /// </summary>
        public virtual void Redo()
        {
            // Empty implementation.
        }
        #endregion
    }

}