windows phone 开发常用小技巧 - 退出应用之升级版（三秒内双击退出）

//设置一个DispatcherTimer，控制三秒内再次点击返回键时执行退出逻辑

            <span>public</span>
            <span>void</span>
            <span> ExitBy2Click(System.ComponentModel.CancelEventArgs e)
        {
            </span>
            <span>if</span> (!<span>IsExit)
            {
</span><span>
                IsExit </span>= <span>true</span><span>;
                e.Cancel </span>= <span>true</span><span>;
                _timer </span>= <span>new</span><span> DispatcherTimer();
                _timer.Start();
                SystemTrayMessage.Instance.StartAdv(</span><span>"</span><span>再按一次退出</span><span>"</span>, <span>3</span>, <span>false</span><span>);
                _timer.Interval </span>= TimeSpan.FromSeconds(<span>3</span><span>);
                _timer.Tick </span>+= (sender, ee) =><span>
                {
                    IsExit </span>= <span>false</span><span>;
                    e.Cancel </span>= <span>false</span><span>;
                    _timer.Stop();
                };

                </span><span>return</span><span>;
            }
            </span><span>else</span><span>
            {       
                </span><span>while</span><span> (NavigationService.BackStack.Any())
                    NavigationService.RemoveBackEntry();
                </span><span>base</span>.OnBackKeyPress(<span>new</span><span> CancelEventArgs());
               </span><span>//</span><span> App.Current.Terminate();
                </span><span>//</span><span>new Microsoft.Xna.Framework.Game().Exit();//wp7</span>
            }