使用阿尔巴哈里(Albarhari)描述的IProgress接口所需的特定工作示例

问题描述

我是C#线程方面的新手.我正在设法弄清如何发出100K Web请求，具有一定程度的并行性，并向GUI实时报告进度:

I am a neophyte at C# threading. I am trying to get my head around how to make 100K web requests, with some degree of parallelism, and report progress real-time to the GUI:

urls processed so far: ######
total moved so far:    ######
timed out so far:      ####3

我正在阅读Albarhari兄弟在 C#5.0中的 C#5.0 中的596ff页，有关进度报告.在这一点上，我看不到如何在Progress实例中以线程安全的方式增加这些计数器的数量，以及UI的更新方式/确切位置.在示例中，EVen专门讨论了写入控制台和写入GUI之间的区别，本书使用Console.WriteLine.我将不胜感激一个示例，该示例准确显示了Progress实例中发生的情况-例如，增加一些int变量并写入文本框.

I am reading pages 596ff in C# 5.0 in a Nutshell by the Albahari brothers, the section on Progress Reporting. At this point, I don't see how in the Progress instance these counters would be incremented in a thread-safe manner, and exactly how/where the UI gets updated. EVen in the example specifically discussing the differences between writing to the console and writing to the GUI, the book uses Console.WriteLine. I'd be grateful for an example showing exactly what occurs in the Progress instance -- incrementing some int variables and writing to a textbox, for example.

推荐答案

我有一个我的博客上的演练，特别指出了警告:

I have a walkthrough on my blog, in particular pointing out the caveats:

• IProgress<T>.Report是异步的，因此，如果您发送的对象是不可变的，则效果最佳.
• 按照惯例，传递给您的TAP方法的IProgress<T> progress可能是null，因此请在报告进度之前进行检查.
• Progress<T>最适合与UI或其他单线程SynchronizationContext一起使用.
• 从Progress<T>的处理程序引发的异常直接进入SynchronizationContext，因此避免引发进度报告处理程序的异常.

• IProgress<T>.Report is asynchronous, so it works best if the object you send it is immutable.
• By convention, the IProgress<T> progress passed into your TAP method may be null, so check for that before reporting progress.
• Progress<T> works best with a UI or other single-threaded SynchronizationContext.
• Exceptions raised from Progress<T>'s handler go directly to the SynchronizationContext, so avoid throwing exceptions from the progress report handler.

还有一个此处的博客帖子和 MSDN文档很好.

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