Simple Asynch Demo in Silverlight

Here's a demo that shows a very simple lambda and delegate based approach to making async calls in Silverlight.

Thanks to MichealGG for the code. See his response to my question on StackOverflow here: http://stackoverflow.com/questions/508177/implementing-a-nested-asynch-call-stack-scenario-in-net

<UserControl x:Class="SilverlightTestApp.Page"

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Width="400" Height="300">

<Grid x:Name="LayoutRoot" Background="White">

<TextBlock Name="ResultsTextBlock"

Width="400" Height="300"

TextWrapping="Wrap"/>

</Grid>

</UserControl>

using System;

using System.Threading;

using System.Windows;

using System.Windows.Controls;

 

 

namespace SilverlightTestApp

{

    public partial class Page : UserControl

    {

        public Page()

        {

            InitializeComponent();

 

        }

 

        private void AsynchDemo()

        {

            ResultsTextBlock.Text = "";

            ResponseWriteLine("BEGIN: AsynchDemo()");

 

            AsyncHelp(

                () => SlowDateTime("The time is now:  "),

                ex => ResultsTextBlock.Text += ex.ToString(),

                bla => ResultsTextBlock.Text += bla.ToString()

                );

            ResponseWriteLine("CALLED: SlowDateTime()");

 

            Action<string> r = ResponseWrite;

 

            for(int x = 0;x<100;x++)

            {

                AsyncHelp(

                    () => RandomSleep(x),

                    ex => ResultsTextBlock.Text += ex.ToString(),

                    r);  //use a delegate instead of a lambda expression

            }

 

            ResponseWriteLine("END: RandomSleep() x 100");

        }

 

        public string RandomSleep(int input)

        {

            Random r = new Random();

            int t = r.Next(10000);

            Thread.Sleep(t);

            return input.ToString() + "."; ;

        }

 

        public void ResponseWrite<T>(T result)

        {

            ResultsTextBlock.Text += result.ToString();

        }

        public void ResponseWriteLine<T>(T result)

        {

            ResultsTextBlock.Text += result.ToString() + Environment.NewLine;

        }

 

        public string SlowDateTime(string text)

        {

 

            Thread.Sleep(5000);

            return text + DateTimeOffset.Now.ToString();

        }

 

        public void AsyncHelp<T>(Func<T> f, Action<Exception> econt, Action<T> cont)

        {

            var t = new Thread((_) =>

            {

                try

                {

                    var res = f();

                    System.Windows.Deployment.Current.Dispatcher.BeginInvoke(() => cont(res));

                }

                catch (Exception ex)

                {

                    System.Windows.Deployment.Current.Dispatcher.BeginInvoke(() => econt(ex));

                }

            });

            t.Start();

        }

 

        private void Button_Click(object sender, RoutedEventArgs e)

        {

            AsynchDemo();

        }

    }

}