重新想象 Windows 8 Store Apps (45) - 多线程之异步编程: IAsyncAction, IAsyncOperation, IAsyncActionWithProgress, IAsyncOperationWithProgress

原文:重新想象 Windows 8 Store Apps (45) - 多线程之异步编程: IAsyncAction, IAsyncOperation, IAsyncActionWithProgress, IAsyncOperationWithProgress[源码下载]

[align=center]重新想象 Windows 8 Store Apps (45) - 多线程之异步编程: IAsyncAction, IAsyncOperation, IAsyncActionWithProgress, IAsyncOperationWithProgress[/align]

作者：webabcd

介绍
重新想象 Windows 8 Store Apps 之 异步编程

IAsyncAction - 无返回值，无进度值

IAsyncOperation - 有返回值，无进度值

IAsyncActionWithProgress - 无返回值，有进度值

IAsyncOperationWithProgress - 有返回值，有进度值

示例
1、演示 IAsyncAction（无返回值，无进度值）的用法
Thread/Async/IAsyncActionDemo.xaml

<Page
x:Class="XamlDemo.Thread.Async.IAsyncActionDemo"
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="120 0 0 0">

<TextBlock Name="lblMsg" FontSize="14.667" />

<Button Name="btnCreateAsyncAction" Content="执行一个 IAsyncAction" Click="btnCreateAsyncAction_Click_1" Margin="0 10 0 0" />

<Button Name="btnCancelAsyncAction" Content="取消" Click="btnCancelAsyncAction_Click_1" Margin="0 10 0 0" />

</StackPanel>
</Grid>
</Page>

Thread/Async/IAsyncActionDemo.xaml.cs

/*
* 演示 IAsyncAction（无返回值，无进度值）的用法
*
* 注：
* 1、WinRT 中的异步功能均源自 IAsyncInfo
* 2、IAsyncAction, IAsyncOperation<TResult>, IAsyncActionWithProgress<TProgress>, IAsyncOperationWithProgress<TResult, TProgress> 均继承自 IAsyncInfo
*
*
* 另：
* Windows.System.Threading.ThreadPool.RunAsync() - 返回的就是 IAsyncAction
*/

using System.Runtime.InteropServices.WindowsRuntime;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace XamlDemo.Thread.Async
{
public sealed partial class IAsyncActionDemo : Page
{
private IAsyncAction _action;

public IAsyncActionDemo()
{
this.InitializeComponent();
}

private IAsyncAction GetAsyncAction()
{
// 通过 System.Runtime.InteropServices.WindowsRuntime.AsyncInfo 创建 IAsyncAction
return AsyncInfo.Run(
(token) => // CancellationToken token
Task.Run(
() =>
{
token.WaitHandle.WaitOne(3000);
token.ThrowIfCancellationRequested();
},
token));
}

private void btnCreateAsyncAction_Click_1(object sender, RoutedEventArgs e)
{
_action = GetAsyncAction();

// 可以 await _action

// IAsyncAction 完成后
_action.Completed =
(asyncInfo, asyncStatus) => // IAsyncAction asyncInfo, AsyncStatus asyncStatus
{
// AsyncStatus 包括：Started, Completed, Canceled, Error
lblMsg.Text = "完成了，AsyncStatus: " + asyncStatus.ToString();
};

lblMsg.Text = "开始执行，3 秒后完成";
}

// 取消 IAsyncAction
private void btnCancelAsyncAction_Click_1(object sender, RoutedEventArgs e)
{
if (_action != null)
_action.Cancel();
}
}
}

2、演示 IAsyncOperation<TResult>（有返回值，无进度值）的用法
Thread/Async/IAsyncOperationDemo.xaml

<Page
x:Class="XamlDemo.Thread.Async.IAsyncOperationDemo"
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="120 0 0 0">

<TextBlock Name="lblMsg" FontSize="14.667" />

<Button Name="btnCreateAsyncOperation" Content="执行一个 IAsyncOperation" Click="btnCreateAsyncOperation_Click_1" Margin="0 10 0 0" />

<Button Name="btnCancelAsyncOperation" Content="取消" Click="btnCancelAsyncOperation_Click_1" Margin="0 10 0 0" />

</StackPanel>
</Grid>
</Page>

Thread/Async/IAsyncOperationDemo.xaml.cs

/*
* 演示 IAsyncOperation<TResult>（有返回值，无进度值）的用法
*
* 注：
* 1、WinRT 中的异步功能均源自 IAsyncInfo
* 2、IAsyncAction, IAsyncOperation<TResult>, IAsyncActionWithProgress<TProgress>, IAsyncOperationWithProgress<TResult, TProgress> 均继承自 IAsyncInfo
*/

using System;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace XamlDemo.Thread.Async
{
public sealed partial class IAsyncOperationDemo : Page
{
private IAsyncOperation<int> _operation;

public IAsyncOperationDemo()
{
this.InitializeComponent();
}

private IAsyncOperation<int> GetAsyncOperation(int x, int y)
{
// 通过 System.Runtime.InteropServices.WindowsRuntime.AsyncInfo 创建 IAsyncOperation<TResult>
return AsyncInfo.Run<int>(
(token) => // CancellationToken token
Task.Run<int>(
() =>
{
token.WaitHandle.WaitOne(3000);
token.ThrowIfCancellationRequested();

// 返回结果
return x * y;
},
token));
}

private void btnCreateAsyncOperation_Click_1(object sender, RoutedEventArgs e)
{
_operation = GetAsyncOperation(10, 10);

// 可以 await _operation

// IAsyncOperation<TResult> 完成后
_operation.Completed =
(asyncInfo, asyncStatus) => // IAsyncAction asyncInfo, AsyncStatus asyncStatus
{
// AsyncStatus 包括：Started, Completed, Canceled, Error
lblMsg.Text = "完成了，AsyncStatus: " + asyncStatus.ToString();

if (asyncStatus == AsyncStatus.Completed)
{
lblMsg.Text += Environment.NewLine;
// 获取异步操作的返回结果
lblMsg.Text += "结果: " + asyncInfo.GetResults().ToString();
}
};

lblMsg.Text = "开始执行，3 秒后完成";
}

// 取消 IAsyncOperation<TResult>
private void btnCancelAsyncOperation_Click_1(object sender, RoutedEventArgs e)
{
if (_operation != null)
_operation.Cancel();
}
}
}

3、演示 IAsyncActionWithProgress<TProgress>（无返回值，有进度值）的用法
Thread/Async/IAsyncActionWithProgressDemo.xaml

<Page
x:Class="XamlDemo.Thread.Async.IAsyncActionWithProgressDemo"
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="120 0 0 0">

<TextBlock Name="lblMsg" FontSize="14.667" />
<TextBlock Name="lblProgress" FontSize="14.667" />

<Button Name="btnCreateAsyncActionWithProgress" Content="执行一个 IAsyncActionWithProgress" Click="btnCreateAsyncActionWithProgress_Click_1" Margin="0 10 0 0" />

<Button Name="btnCancelAsyncActionWithProgress" Content="取消" Click="btnCancelAsyncActionWithProgress_Click_1" Margin="0 10 0 0" />

</StackPanel>
</Grid>
</Page>

Thread/Async/IAsyncActionWithProgressDemo.xaml.cs

/*
* 演示 IAsyncActionWithProgress<TProgress>（无返回值，有进度值）的用法
*
* 注：
* 1、WinRT 中的异步功能均源自 IAsyncInfo
* 2、IAsyncAction, IAsyncOperation<TResult>, IAsyncActionWithProgress<TProgress>, IAsyncOperationWithProgress<TResult, TProgress> 均继承自 IAsyncInfo
*/

using System.Runtime.InteropServices.WindowsRuntime;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace XamlDemo.Thread.Async
{
public sealed partial class IAsyncActionWithProgressDemo : Page
{
private IAsyncActionWithProgress<int> _action;

public IAsyncActionWithProgressDemo()
{
this.InitializeComponent();
}

private IAsyncActionWithProgress<int> GetAsyncActionWithProgress()
{
// 通过 System.Runtime.InteropServices.WindowsRuntime.AsyncInfo 创建 IAsyncActionWithProgress<TProgress>
return AsyncInfo.Run<int>(
(token, progress) => // CancellationToken token, IProgress<TProgress> progress
Task.Run(
() =>
{
// 报告进度（进度是一个 int 值）
progress.Report(0);

int percent = 0;
while (percent < 100)
{
token.WaitHandle.WaitOne(100);
token.ThrowIfCancellationRequested();

percent++;

// 报告进度（进度是一个 int 值）
progress.Report(percent);
}
},
token));
}

private void btnCreateAsyncActionWithProgress_Click_1(object sender, RoutedEventArgs e)
{
_action = GetAsyncActionWithProgress();

// 可以 await _action

// IAsyncActionWithProgress<TProgress> 完成后
_action.Completed =
(asyncInfo, asyncStatus) => // IAsyncAction asyncInfo, AsyncStatus asyncStatus
{
// AsyncStatus 包括：Started, Completed, Canceled, Error
lblMsg.Text = "完成了，AsyncStatus: " + asyncStatus.ToString();
};

// IAsyncActionWithProgress<TProgress> 接收到进度后
_action.Progress =
(asyncInfo, progressInfo) => // IAsyncActionWithProgress<TProgress> asyncInfo, TProgress progressInfo
{
// 进度是一个 int 值
lblProgress.Text = "进度: " + progressInfo.ToString();
};

lblMsg.Text = "开始执行";
}

// 取消 IAsyncActionWithProgress<TProgress>
private void btnCancelAsyncActionWithProgress_Click_1(object sender, RoutedEventArgs e)
{
if (_action != null)
_action.Cancel();
}
}
}

4、演示 IAsyncOperationWithProgress<TResult, TProgress>（有返回值，有进度值）的用法
Thread/Async/IAsyncOperationWithProgressDemo.xaml

<Page
x:Class="XamlDemo.Thread.Async.IAsyncOperationWithProgressDemo"
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="120 0 0 0">

<TextBlock Name="lblMsg" FontSize="14.667" />
<TextBlock Name="lblProgress" FontSize="14.667" />

<Button Name="btnCreateAsyncOperationWithProgress" Content="执行一个 IAsyncOperationWithProgress" Click="btnCreateAsyncOperationWithProgress_Click_1" Margin="0 10 0 0" />

<Button Name="btnCancelAsyncOperationWithProgress" Content="取消" Click="btnCancelAsyncOperationWithProgress_Click_1" Margin="0 10 0 0" />

</StackPanel>
</Grid>
</Page>

Thread/Async/IAsyncOperationWithProgressDemo.xaml.cs

/*
* 演示 IAsyncOperationWithProgress<TResult, TProgress>（有返回值，有进度值）的用法
*
* 注：
* 1、WinRT 中的异步功能均源自 IAsyncInfo
* 2、IAsyncAction, IAsyncOperation<TResult>, IAsyncActionWithProgress<TProgress>, IAsyncOperationWithProgress<TResult, TProgress> 均继承自 IAsyncInfo
*
*
* 另：
* Windows.Web.Syndication.SyndicationClient.RetrieveFeedAsync() - 返回的就是 IAsyncOperationWithProgress<TResult, TProgress>
*/

using System;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace XamlDemo.Thread.Async
{
public sealed partial class IAsyncOperationWithProgressDemo : Page
{
private IAsyncOperationWithProgress<string, int> _operation;

public IAsyncOperationWithProgressDemo()
{
this.InitializeComponent();
}

private IAsyncOperationWithProgress<string, int> GetAsyncOperationWithProgress()
{
// 通过 System.Runtime.InteropServices.WindowsRuntime.AsyncInfo 创建 IAsyncOperationWithProgress<TResult, TProgress>
return AsyncInfo.Run<string, int>(
(token, progress) =>
Task.Run<string>(
() =>
{
// 报告进度（进度是一个 int 值）
progress.Report(0);

int percent = 0;
while (percent < 100)
{
token.WaitHandle.WaitOne(100);
token.ThrowIfCancellationRequested();

percent++;

// 报告进度（进度是一个 int 值）
progress.Report(percent);
}

// 返回结果
return "成功了";
},
token));
}

private void btnCreateAsyncOperationWithProgress_Click_1(object sender, RoutedEventArgs e)
{
_operation = GetAsyncOperationWithProgress();

// 可以 await _operation

// IAsyncOperationWithProgress<TResult, TProgress> 完成后
_operation.Completed =
(asyncInfo, asyncStatus) => // IAsyncAction asyncInfo, AsyncStatus asyncStatus
{
// AsyncStatus 包括：Started, Completed, Canceled, Error
lblMsg.Text = "完成了，AsyncStatus: " + asyncStatus.ToString();

if (asyncStatus == AsyncStatus.Completed)
{
lblMsg.Text += Environment.NewLine;
// 获取异步操作的返回结果
lblMsg.Text += "结果: " + asyncInfo.GetResults().ToString();
}
};

// IAsyncOperationWithProgress<TResult, TProgress> 接收到进度后
_operation.Progress =
(asyncInfo, progressInfo) => // IAsyncActionWithProgress<TProgress> asyncInfo, TProgress progressInfo
{
// 进度是一个 int 值
lblProgress.Text = "进度: " + progressInfo.ToString();
};

lblMsg.Text = "开始执行";
}

// 取消 IAsyncOperationWithProgress<TResult, TProgress>
private void btnCancelAsyncOperationWithProgress_Click_1(object sender, RoutedEventArgs e)
{
if (_operation != null)
_operation.Cancel();
}
}
}

OK
[源码下载]