Windows 8 Store Apps Learning (44) Multi-thread asynchronous programming

Multi-thread Asynchronous programming: Classic and newest asynchronous programming model, Iasyncinfo and Task conversion

Introduced

Re-imagine the asynchronous programming of Windows 8 Store Apps

Classic Asynchronous Programming model (IAsyncResult)

The latest asynchronous programming model (async and await)

Convert Iasyncinfo into a Task

Convert Task to Iasyncinfo

Example

1, using the classic asynchronous programming model (IAsyncResult) to implement a class to support asynchronous operations

Thread/async/classicasync.cs

* * Using the Classic Asynchronous programming model (IAsyncResult) to implement a class/using System that supports asynchronous operations;
Using System.Collections.Generic;
Using System.Linq;
Using System.Text;
Using System.Threading;
    
Using System.Threading.Tasks;  Namespace XamlDemo.Thread.Async {public class Classicasync {private delegate string hellodelegate (string
    
        name);
    
        Private Hellodelegate _hellodelegate;
        Public Classicasync () {_hellodelegate = new hellodelegate (Hello); private string Hello (string name) {new ManualResetEvent (false).
            WaitOne (3000);
        Return "Hello:" + name;
        //Begin method Public IAsyncResult Beginrun (string name, AsyncCallback callback, Object State) {//new thread, to execute the Hello () method, callback is a callback, state is the context return _hellodelegate.begininvoke (name, callback
        , state);
          The//End method public string Endrun (IAsyncResult ar) {  if (AR = null) throw new NullReferenceException ("IAsyncResult cannot be null");
        return _hellodelegate.endinvoke (AR); }
    }
}

Thread/async/classicasyncdemo.xaml

<page
    x:class= "XamlDemo.Thread.Async.ClassicAsyncDemo"
    xmlns= "http://schemas.microsoft.com/winfx/ 2006/xaml/presentation "
    xmlns:x=" Http://schemas.microsoft.com/winfx/2006/xaml "
    xmlns:local=" using: XamlDemo.Thread.Async "
    xmlns:d=" http://schemas.microsoft.com/expression/blend/2008 "
    xmlns:mc=" http:// schemas.openxmlformats.org/markup-compatibility/2006 "
    mc:ignorable=" D ">
    
    <grid background=" Transparent ">
        <stackpanel margin=" 0 0 0 ">
    
            <textblock name=" lblmsg "fontsize=" 14.667 "/>
    
            <button name= "Btniasyncresult" content= "IAsyncResult Demo" click= "btniasyncresult_click_1" margin= "0 10 0 0" />
    
        </StackPanel>
    </Grid>
</Page>

Thread/async/classicasyncdemo.xaml.cs

* * Demonstrates how to perform asynchronous operations through the classic asynchronous programming model (IASYNCRESULT) * IAsyncResult-Asynchronous Operation result * asyncstate-context * iscompleted-Asynchronous operation Completed * AsyncWaitHandle-Gets the System.Threading.WaitHandle object that waits for the asynchronous operation to complete (via WaitHandle.WaitOne () on the current thread) * * usin
G System;
Using Windows.UI.Xaml;
    
Using Windows.UI.Xaml.Controls; Namespace XamlDemo.Thread.Async {public sealed partial class Classicasyncdemo:page {SYSTEM.THREADING.S
    
        Ynchronizationcontext _synccontext; Public Classicasyncdemo () {this.
    
            InitializeComponent ();
        Gets the current UI thread _synccontext = System.Threading.SynchronizationContext.Current; } private void Btniasyncresult_click_1 (object sender, RoutedEventArgs e) {Classicasync C
    
            Lassicasync = new Classicasync ();
    
            IAsyncResult ar = Classicasync.beginrun ("Webabcd", New AsyncCallback (Callback), classicasync);
        Lblmsg.text = "Start execution, 3 seconds to complete";
}    
        private void Callback (IAsyncResult ar) {classicasync Classicasync = (classicasync) ar.
            asyncstate;
    
            string result = Classicasync.endrun (AR);
                _synccontext.post ((CTX) => {lblmsg.text = result;
        }, NULL); }
    }
}