how to dynamically change Textblock

Question

I am newbie in wpf and c#. Trying to make real-time notifications, I have a textblock that contains the latest information from webpage.Every 5 minutes i receive new information,which should be displayed on textblock, I have succesfully received information, but when I set this as property of textblock, it doesnt change,it still shows first received info. My code:

    async void GetChanges()
    {
        Rootobject allEarthquakes = await Async();
        int count = allEarthquakes.features.Length;

        LastData.Text = "Последнее землетрясение: \nМагнитуда: " + allEarthquakes.features[count - 1].properties.mag + "\nРасположение: " + allEarthquakes.features[count - 1].properties.place + "\nВремя: " + DateTimeOffset.FromUnixTimeMilliseconds(allEarthquakes.features[count - 1].properties.time) + "\nГлубина: " + allEarthquakes.features[count - 1].geometry.coordinates[2] + "\nID: " + allEarthquakes.features[count - 1].id;


    }
    Task<Rootobject> Async()
    {
        string path = @"C:\data\data.json";
        string json;
        string url = @"https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson";
        using (WebClient client = new WebClient())
        {
            json = client.DownloadString(url);
        }
        Rootobject allEarthquakes = JsonConvert.DeserializeObject<Rootobject>(json);
        int count = allEarthquakes.features.Length;
        if (File.Exists(path))
        {
            File.Delete(path);
        }
        Directory.CreateDirectory(@"C:\data");
        using (StreamWriter stream = File.CreateText(path))
        {
            stream.Write(json);
        }
        return Task.Run(() =>
            allEarthquakes);
    }

Where, LastData is Textblock

Answer 1

If the TextBlock refreshes when you change tabs than it sounds to me like you are not implementing the INotifyPropertyChanged interface. Normally you would bind TextBlock.Text in xaml like so

<TextBlock Text={Binding UpdateText} />

And then have some string property UpdateText in your code-behind, see this MSDN article