C#AngleSharp解析流有什么问题?

时间:2017-03-15 14:48:36

标签: c# asynchronous anglesharp

问题在于,只有一部分写入文档,而不是所需的标题数。控制台输出正常。

这里代码:

using AngleSharp;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace AngleSharp

{
    class Program
    {
        static void Main(string[] args)
        {
             Console.WriteLine("ok start");
             Mainpar();
             Console.ReadKey();
        }
    static async Task Mainpar()
    {
        // Setup the configuration to support document loading
        var config = Configuration.Default.WithDefaultLoader();
        // Load the names of all The Big Bang Theory episodes from Wikipedia
        var address = "https://en.wikipedia.org/wiki/List_of_The_Big_Bang_Theory_episodes";
        // Asynchronously get the document in a new context using the configuration
        var document = await BrowsingContext.New(config).OpenAsync(address);
        // This CSS selector gets the desired content
        var cellSelector = "tr.vevent td:nth-child(3)";
        // Perform the query to get all cells with the content
        var cells = document.QuerySelectorAll(cellSelector);
        // We are only interested in the text - select it with LINQ
        var titles = cells.Select(m => m.TextContent).ToArray();

        var allnum = titles.Count();

        System.IO.StreamWriter sw = new System.IO.StreamWriter(@"C:\bd.txt");
        for (int i = 0; i <= allnum; i++)
        {
          sw.WriteLine(titles[i] + i);
          Console.WriteLine(titles[i] + i);
        }      
      }
   }
}

不知道问题是什么。不同数量的标题写入文件,后者不完全。可能线程被阻止或程序只是关闭..我不明白它是如何取决于

1 个答案:

答案 0 :(得分:0)

您应该正确关闭流。可能发生的是当程序关闭时强制关闭流而不刷新文件。请尝试换行使用using语句:

    using (var sw = new System.IO.StreamWriter(@"C:\bd.txt"))
    {
        for (int i = 0; i <= allnum; i++)
        {
            sw.WriteLine(titles[i] + i);
            Console.WriteLine(titles[i] + i);
        }
    }

using语句确保正确关闭流并在完成使用后将其刷新到磁盘。

此外,由于您未在await方法中使用MainPar,也未在主方法中使用await调用它,因此没有充分的理由对其进行标记async。它应该是static void。除非您异步调用它,否则只需将async关键字添加到方法中就无济于事。如果您希望MainPar真的是异步,可以使用StreamWriter.WriteLineAsync(string)方法:

    using (var sw = new System.IO.StreamWriter(@"C:\bd.txt"))
    {
        for (int i = 0; i <= allnum; i++)
        {
            await sw.WriteLineAsync(titles[i] + i);
            Console.WriteLine(titles[i] + i);
        }
    }

然后您可以在Main方法中调用,如下所示:

    static void Main(string[] args)
    {
        Task.Run(async () =>
        {
            Console.WriteLine("ok start");
            await Mainpar();
            Console.ReadKey();
        }).GetAwaiter().GetResult();
    }