使用异步方法在Windows Phone 8.1中加载页面

Question

I want to display a loding circle bar, while a page in Windows Phone is loading. The latency is due to an async method, which donwloads a Json file and concert it to List of objects. Is it a problem, if the async method is in another Class ? Also, how Can I get back the result of aysnc method in another class/page ?

Answer 1

Write your code in separate class

public class Result 
{
   public string Message {get;set}
}
public class Utility
{
   public async Task<Result> GetJson()
   {
       //do something here
       return result;
   }
}

Then call it like this:

LoadingIndicator.Visibility = Visibility.Visible;
await Utility.GetJson()
LoadingIndicator.Visibility = Visibility.Collapsed;

And add this to your page XAML:

<Grid>
    <!-- Other UI elements -->
    <StackPanel x:Name="LoadingIndicator" VerticalAlignment="Center" HorizontalAlignment="Center" Visibility="Collapsed">
        <TextBlock Text="Loading..."/>
        <ProgressRing IsActive="True" VerticalAlignment="Center"/>
    </StackPanel>
</Grid>