/source/library/Interlace/Utilities/DelayedEvent.cs

#region Using Directives and Copyright Notice



// Copyright (c) 2007-2010, Computer Consultancy Pty Ltd

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//     * Redistributions of source code must retain the above copyright

//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above copyright

//       notice, this list of conditions and the following disclaimer in the

//       documentation and/or other materials provided with the distribution.

//     * Neither the name of the Computer Consultancy Pty Ltd nor the

//       names of its contributors may be used to endorse or promote products

//       derived from this software without specific prior written permission.

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 

// ARE DISCLAIMED. IN NO EVENT SHALL COMPUTER CONSULTANCY PTY LTD BE LIABLE 

// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 

// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 

// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 

// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 

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// DAMAGE.



using System;

using System.Collections.Generic;

using System.Text;

using System.Windows.Forms;



#endregion



namespace Interlace.Utilities

{

    /// <summary>

    /// Hooks an event of any type and uses it to start a countdown that triggers a second

    /// event. Any event arguments of the first event are not kept.

    /// </summary>

    /// <typeparam name="TEventArgs">The event that triggers the countdown.</typeparam>

    public class DelayedEvent<TEventArgs> where TEventArgs : EventArgs

    {

        public event EventHandler Triggered;

        public event EventHandler<TEventArgs> TriggeredWithArgs;



        Timer _timer;



        TimeSpan _lag;



        bool _isActive;

        DateTime _elapsesAt;



        object _delayedSender;

        TEventArgs _delayedArgs;



        public DelayedEvent(Form owningForm)

        {

            _isActive = false;



            _timer = new Timer();

            _timer.Interval = 100;

            _timer.Start();



            _timer.Tick += new EventHandler(_timer_Tick);



            owningForm.FormClosed += new FormClosedEventHandler(owningForm_FormClosed);

        }



        void _timer_Tick(object sender, EventArgs e)

        {

            if (_isActive && DateTime.Now > _elapsesAt)

            {

                _isActive = false;



                object delayedSender = _delayedSender;

                TEventArgs delayedArgs = _delayedArgs;



                _delayedSender = null;

                _delayedArgs = null;



                if (Triggered != null) Triggered(this, EventArgs.Empty);

                if (TriggeredWithArgs != null) TriggeredWithArgs(delayedSender, delayedArgs);

            }

        }



        void owningForm_FormClosed(object sender, FormClosedEventArgs e)

        {

            _timer.Stop();



            _timer.Tick -= new EventHandler(_timer_Tick);

            (sender as Form).FormClosed -= new FormClosedEventHandler(owningForm_FormClosed);

        }



        public void HandleTriggeringEvent(object sender, TEventArgs e)

        {

            _isActive = true;

            _elapsesAt = DateTime.Now + Lag;



            _delayedSender = sender;

            _delayedArgs = e;

        }



        public TimeSpan Lag

        {

            get { return _lag; }

            set { _lag = value; }

        }

    }

}