Window 8.1 计时器功能及图片切换

  <Canvas Margin="450,0" Width="795" Grid.Column="1">
                 <Image Margin="15,15,15,15" Width="64" Height="64" Source="image/Content/clock.png"></Image>
                 <TextBlock  Text="{Binding TimerContext}" FontSize="45" Height="50" Width="170" Margin="90,20,0,0" />
                 <Button  Margin="280,20"  FontSize="28" Width="180" Height="50" HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch" Command="{Binding StartAndPauseCommand}" >
                     <Button.Background>
                         <SolidColorBrush  Color="#FFE0F1F9"/>
                     </Button.Background>
                     <Grid>
                         <Grid.ColumnDefinitions>
                             <ColumnDefinition Width="44"/>
                             <ColumnDefinition Width="*"/>
                         </Grid.ColumnDefinitions>
                         <Image  Source="{Binding StartAndPauseButtonImage}" Width="40" Height="35" Margin="-1,-1,5,-2"></Image>
                         <TextBlock   Grid.Column="1" Margin="10,-5" Foreground="#FF00C5A2" Text="{Binding  ImageOperationText}" Width="100" />
                     </Grid>
                 </Button>
     </Button>

  private TimeSpan _timeSpan;
         void dispatcherTimer_Tick(object sender, object e)
         {

             _timeSpan = _timeSpan.Add(new TimeSpan(, , ));
             TimerContext = _timeSpan.ToString();

         }
  public string ImageOperationText
         {
             get { return imageOperationText; }
             set
             {
                 if (imageOperationText == value) return;
                 imageOperationText = value;
                 base.RaisePropertyChanged("ImageOperationText");
             }
         }

         private string timerContext = TicketContentConst.TimerContextText;
         public string TimerContext
         {

             get { return timerContext; }
             set
             {
                 if (timerContext == value) return;
                 timerContext = value;
                 base.RaisePropertyChanged("TimerContext");
             }
         }
  #region Command
         private RelayCommand startAndPauseCommand;
         public RelayCommand StartAndPauseCommand
         {
             get
             {
                 if (startAndPauseCommand == null)
                     startAndPauseCommand = new RelayCommand(startAndPause);
                 return startAndPauseCommand;
             }
         }
  #endregion
  /// <summary>
         /// dispatcherTimer Operations
         /// </summary>
         private void startAndPause()
         {
             if (!isTimerStart)
             {

                 dispatcherTimer.Start();
                 StartAndPauseButtonImage = TicketContentConst.PauseImagePath;
                 ImageOperationText = TicketContentConst.PauseContentText;
                 if (startDateTime == DateTime.MinValue)
                 {
                     startDateTime = DateTime.Now;
                 }

             }
             else
             {

                 dispatcherTimer.Stop();
                 ImageOperationText = TicketContentConst.StartContentText;
                 StartAndPauseButtonImage = TicketContentConst.StartImagePath;

             }
             isTimerStart = !isTimerStart;

         }
         /// <summary>
         /// 计时器设置
         /// </summary>
         public void DispatcherTimerSetup()
         {

             dispatcherTimer = new DispatcherTimer();
             dispatcherTimer.Tick += dispatcherTimer_Tick;
             dispatcherTimer.Interval = new TimeSpan(, , );
             _timeSpan = new TimeSpan();

         }

</Canvas>