/// <summary>
        /// 在此页将要在 Frame 中显示时进行调用。
        /// </summary>
        /// <param name="e">描述如何访问此页的事件数据。
        /// 此参数通常用于配置页。</param>
        protected async override void OnNavigatedTo(NavigationEventArgs e)
        {
            Windows.Phone.UI.Input.HardwareButtons.BackPressed += (sender, arg) => { arg.Handled = true; };
            if (StaticObj.user is HeartLink_Lib.Student)
            {
                gridForStudent.Visibility    = Visibility.Visible;
                gridForSupervisor.Visibility = Visibility.Collapsed;
            }
            else
            {
                gridForSupervisor.Visibility = Visibility.Visible;
                gridForStudent.Visibility    = Visibility.Collapsed;
                AskOffList = new ContentCollection <AskOffContent>();
                StaticObj.SendPackets(DataParser.Str2Packets(Convert.ToInt32(CommandCode.GetAskOff), ""));

                Packet[] incommingAskOff = await StaticObj.ReceivePackets();

                if (DataParser.GetPacketCommandCode(incommingAskOff[0]) == Convert.ToInt32(CommandCode.ReturnAskOff))
                {
                    List <Dictionary <string, string> > jsonAskOffs = JsonParser.DeserializeListOfDictionaryObject(DataParser.Packets2Str(incommingAskOff));

                    foreach (Dictionary <string, string> con in jsonAskOffs)
                    {
                        AskOffContent temp = new AskOffContent();
                        temp.Reason = con["REASON"];
                        temp.ID     = con["ID"];
                        temp.Date   = con["ASKOFFDATE"];
                        temp.Time   = con["ASKOFFTIME"];
                        AskOffList.Add(temp);
                    }

                    display.ItemsSource = AskOffList;
                }
            }
        }
        private async void confirm_Click(object sender, RoutedEventArgs e)
        {
            #region Stu
            if (StaticObj.user is Student)
            {
                Dictionary <string, string> askoffPair = new Dictionary <string, string>();
                askoffPair.Add("ID", StaticObj.user.ID);
                askoffPair.Add("ASKOFFDATE", date.Date.ToString().Split(new char[] { ' ' })[0]);
                askoffPair.Add("ASKOFFTIME", String.Format("{0}~{1}", fromTime.Time.ToString().Substring(0, 5), toTime.Time.ToString().Substring(0, 5)));
                askoffPair.Add("REASON", reasonTxtBox.Text.Trim());
                askoffPair.Add("ISSOLVED", "0");
                StaticObj.SendPackets(DataParser.Str2Packets(Convert.ToInt32(CommandCode.SendAskOff), JsonParser.SerializeObject(askoffPair)));

                Packet[] incommingAskOff = await StaticObj.ReceivePackets();

                if (DataParser.GetPacketCommandCode(incommingAskOff[0]) == Convert.ToInt32(CommandCode.ReturnAskOff))
                {
                    if (Convert.ToInt32(DataParser.Packets2Str(incommingAskOff)) != 0)
                    {
                        await(new MessageDialog("已上传")).ShowAsync();
                        Frame.BackStack.RemoveAt(Frame.BackStackDepth - 1);
                        Frame.Navigate(typeof(Main));
                    }
                    else
                    {
                        await(new MessageDialog("上传失败")).ShowAsync();
                    }
                }
            }
            #endregion
            #region Sup
            else
            {
                AskOffContent selected = (AskOffContent)display.SelectedItem;
                Dictionary <string, string> solvePair = new Dictionary <string, string>();
                solvePair.Add("ID", selected.ID);
                solvePair.Add("ASKOFFDATE", selected.Date);
                solvePair.Add("ASKOFFTIME", selected.Time);
                StaticObj.SendPackets(DataParser.Str2Packets(Convert.ToInt32(CommandCode.SolveAskOff), JsonParser.SerializeObject(solvePair)));

                Packet[] incomming = await StaticObj.ReceivePackets();

                int solveResult = DataParser.GetPacketCommandCode(incomming[0]);
                if (solveResult == Convert.ToInt32(CommandCode.Succeed))
                {
                    await(new MessageDialog("已解决")).ShowAsync();
                    display.Items.RemoveAt(display.SelectedIndex);
                }
                else
                {
                    await(new MessageDialog("错误")).ShowAsync();
                }
            }
            #endregion
        }