title: Simple Arithmetic Operations on Binded Text Property of windows phone 8 app XAML
body: <p>I'm developing a Windows Phone 8.1 App. In the app I'm parsing a Json data. From the parsed data, I'm populating a GridView. The JsonData consists of temperature in Kelvin. But I want to change the temperature in  Celsius while binding the data in the TextBlock.</p>
  
  <p>Here's the Code in XAML</p>
  
  <pre><code>&lt;StackPanel&gt;
          &lt;TextBlock x:Name="tblk1" FontSize="20" /&gt;
          &lt;TextBlock x:Name="tblk2" FontSize="20" Margin="0,5,0,0"/&gt;
          &lt;TextBlock x:Name="tblk3" FontSize="20" Margin="0,5,0,0"/&gt;
  
  
          &lt;ScrollViewer VerticalScrollBarVisibility="Visible" VerticalScrollMode="Enabled" &gt;
              &lt;GridView x:Name="tempList" ItemsSource="{Binding}"&gt;
                  &lt;GridView.ItemTemplate&gt;
                      &lt;DataTemplate&gt;
                          &lt;StackPanel Margin="10" Background="DarkGreen"&gt;
                              &lt;StackPanel Margin="5"&gt;
                                  &lt;TextBlock Text="{Binding dt}" FontSize="15" /&gt;
                                  &lt;TextBlock Text="{Binding temp.day}" FontSize="15" /&gt;
                                  &lt;TextBlock Text="{Binding temp.min}" FontSize="15" /&gt;
                                  &lt;TextBlock Text="{Binding temp.max}" FontSize="15" /&gt;
                              &lt;/StackPanel&gt;
                          &lt;/StackPanel&gt;
                      &lt;/DataTemplate&gt;
                  &lt;/GridView.ItemTemplate&gt;
              &lt;/GridView&gt;
          &lt;/ScrollViewer&gt;
  
      &lt;/StackPanel&gt;
  </code></pre>
  
  <p>And here's code from the C# </p>
  
  <pre><code> protected override void OnNavigatedTo(NavigationEventArgs e)
      {
          RootObject obj = JsonConvert.DeserializeObject&lt;RootObject&gt;(MainPage.jsonReturn);
          tblk1.Text = obj.city.name;
          tblk2.Text = obj.cod;
          tblk3.Text = obj.message.ToString();
          tempList.DataContext = null;
          tempList.DataContext = obj.list;
  
      }
  </code></pre>
  
  <p>In the output, Here the min and max temp is shown in Kelvin. How do I show it in Celsius? </p>
  
  <blockquote>
    <p>PS There's no any way to change the Incoming JsonData in Celsius. It
    has to changed in runtime.</p>
  </blockquote>