這一篇只能算是備註，非同步任務這一塊自己還要多複習作業系統。

下面是XAML：

<phone:PhoneApplicationPage
    x:Class="AsyncTask.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">
    <Grid HorizontalAlignment="Left" Height="768" VerticalAlignment="Top" Width="480">
        <Button Content="非同步" HorizontalAlignment="Left" Margin="178,522,0,0" VerticalAlignment="Top" RenderTransformOrigin="-1.348,0.043" Click="Button_Click"/>
        <Button Content="UI" HorizontalAlignment="Left" Margin="199,430,0,0" VerticalAlignment="Top" Click="Button_Click_1"/>
        <TextBlock x:Name="Tb" HorizontalAlignment="Left" Margin="165,298,0,0" TextWrapping="Wrap" Text="TextBlock" VerticalAlignment="Top" Height="66" Width="155"/>
        <Button Content="同步" HorizontalAlignment="Left" Margin="178,617,0,0" VerticalAlignment="Top" Click="Button_Click_2"/>
    </Grid>


</phone:PhoneApplicationPage>
 

下面是CS：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using AsyncTask.Resources;
using System.Threading.Tasks;
using System.Threading;

namespace AsyncTask
{
    public partial class MainPage : PhoneApplicationPage
    {
        private int num = 0;
        // 建構函式
        public MainPage()
        {
            InitializeComponent();

        }

        private async void  Button_Click(object sender, RoutedEventArgs e)
        {
            await A();
        }

        private async Task A()
        {
            await Task.Delay(10000);
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            Tb.Text = num.ToString();
        }

        private async void Button_Click_2(object sender, RoutedEventArgs e)
        {
            Thread.Sleep(10000);
        }

    }
}
 

下面是程式截圖：

當按下非同步按鈕的時候再按UI按鈕TEXTBLOCK會改變，當按下同步按鈕按UI按鈕要等10S的時間才有相應。

注意：

非同步方法型別只有void ,Task或Task<TResult>

async宣告該方法是非同步，當時實際上此時並沒有起非同步，await才是真正進行非同步處理。

await something，只有當something執行完畢之後await之後的程式碼才會執行。

await關鍵字必須要在async關鍵字內

例項二：

這個例項告訴了我們Lambda表示式很重要。

<phone:PhoneApplicationPage
    x:Class="PhoneApp6.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">
    <Grid HorizontalAlignment="Left" Height="768" VerticalAlignment="Top" Width="480">
        <TextBox Loaded="txt_Loaded" Name="txt" HorizontalAlignment="Left" Height="72" TextWrapping="Wrap" Text="0" VerticalAlignment="Top" Width="456" Margin="14,303,0,0"/>
        <Button Content="Button" HorizontalAlignment="Left" Margin="171,455,0,0" VerticalAlignment="Top"/>
    </Grid>

</phone:PhoneApplicationPage>
 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using PhoneApp6.Resources;
using System.Threading.Tasks;
using System.Threading;

namespace PhoneApp6
{
    public partial class MainPage : PhoneApplicationPage
    {
        // 建構函式
        public MainPage()
        {
            InitializeComponent();
        }

        private async void txt_Loaded(object sender, RoutedEventArgs e)
        {
            while (true)
            {
                String t = await getTime();
                txt.Text = t;
            }
        }


        private async Task<String> getTime()
        {
            return await Task<String>.Run<String>(() =>
                {
                    Thread.Sleep(1000);
                    return DateTime.Now.Hour + "--" + DateTime.Now.Minute + "--" + DateTime.Now.Second + "--" + DateTime.Now.Millisecond;
                });
        }
    }
}

一秒之後TextBox就會重新整理顯示當前的時間，可以通過點選Button知道UI執行緒是沒有被阻塞的。