C.B.R.

// ****************************************************************************
// <copyright file="WeakActionGeneric.cs" company="GalaSoft Laurent Bugnion">
// Copyright © GalaSoft Laurent Bugnion 2009-2011
// </copyright>
// ****************************************************************************
// <author>Laurent Bugnion</author>
// <email>laurent@galasoft.ch</email>
// <date>18.9.2009</date>
// <project>GalaSoft.MvvmLight</project>
// <web>http://www.galasoft.ch</web>
// <license>
// See license.txt in this solution or http://www.galasoft.ch/license_MIT.txt
// </license>
// ****************************************************************************

using System;

namespace CBR.Core.Helpers
{
    /// <summary>
    /// Stores an Action without causing a hard reference
    /// to be created to the Action's owner. The owner can be garbage collected at any time.
    /// </summary>
    /// <typeparam name="T">The type of the Action's parameter.</typeparam>
    ////[ClassInfo(typeof(Messenger))]
    public class WeakEventAction<T> : WeakEventAction, IExecuteWithObject
    {
        private readonly Action<T> _action;

        /// <summary>
        /// Initializes a new instance of the WeakAction class.
        /// </summary>
        /// <param name="target">The action's owner.</param>
        /// <param name="action">The action that will be associated to this instance.</param>
        public WeakEventAction(object target, Action<T> action)
            : base(target, null)
        {
            _action = action;
        }

        /// <summary>
        /// Gets the Action associated to this instance.
        /// </summary>
        public new Action<T> Action
        {
            get
            {
                return _action;
            }
        }

        /// <summary>
        /// Executes the action. This only happens if the action's owner
        /// is still alive. The action's parameter is set to default(T).
        /// </summary>
        public new void Execute()
        {
            if (_action != null
                && IsAlive)
            {
                _action(default(T));
            }
        }

        /// <summary>
        /// Executes the action. This only happens if the action's owner
        /// is still alive.
        /// </summary>
        /// <param name="parameter">A parameter to be passed to the action.</param>
        public void Execute(T parameter)
        {
            if (_action != null
                && IsAlive)
            {
                _action(parameter);
            }
        }

        /// <summary>
        /// Executes the action with a parameter of type object. This parameter
        /// will be casted to T. This method implements <see cref="IExecuteWithObject.ExecuteWithObject" />
        /// and can be useful if you store multiple WeakAction{T} instances but don't know in advance
        /// what type T represents.
        /// </summary>
        /// <param name="parameter">The parameter that will be passed to the action after
        /// being casted to T.</param>
        public void ExecuteWithObject(object parameter)
        {
            var parameterCasted = (T) parameter;
            Execute(parameterCasted);
        }
    }
}