#370 – Binding a Label’s Content to the Current Date and Time, part II

You can bind a Label control’s Content property to the DateTime.Now property to display the current date or time, but the label will not update when the time changes.

To get a Label control that continuously updates with the current time, you can bind to a property that updates periodically and notifies us using the INotifyPropertyChanged interface.  We can do this by creating a timer that updates a DateTime property whenever it ticks.

Here’s the XAML:

        <Label Content="{Binding CurrentDateAndTime}" ContentStringFormat="Current time - {0:T}"/>

In the code-behind, we define the property and set up a timer.

        public DateTime CurrentDateAndTime { get; set; }

        public MainWindow()
        {
            this.InitializeComponent();
            this.DataContext = this;

            DispatcherTimer dayTimer = new DispatcherTimer();
            dayTimer.Interval = TimeSpan.FromMilliseconds(500);
            dayTimer.Tick += new EventHandler(dayTimer_Tick);
            dayTimer.Start();
        }

Whenever the timer fires, we update our property and fire the INotifyPropertyChanged.PropertyChanged event.

        void dayTimer_Tick(object sender, EventArgs e)
        {
            CurrentDateAndTime = DateTime.Now;

            PropertyChanged(this, new PropertyChangedEventArgs("CurrentDateAndTime"));
        }

The end result:

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