在多线程应用程序中的回调函数

huangapple
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英文:

a callback in a multithreaded application

问题

以下是您要翻译的代码部分：

  1. 我的应用程序处理目录（每个文件在单独的线程中），并在运行时将信息显示在屏幕上（我使用richtextbox）。
  3. 这是我的代码：
  5. class FilesHandler
  6. {
  7.     private List<string> PathesOfFiles = new List<string>();
  9.     public void LoadPathes(string pathOfDirectory)
  10.     {
  11.         string[] allfiles = Directory.GetFiles(pathOfDirectory);
  12.         foreach (string filename in allfiles)
  13.         {
  14.             PathesOfFiles.Add(filename);
  15.         }
  16.     }
  18.     public void HandleEachFile(RichTextBox RTB)
  19.     {
  20.         foreach (string path in PathesOfFiles)
  21.         {
  22.             new Thread(() => { CalculateThread(RTB, path); }).Start();
  23.         }
  24.     }
  26.     private void CalculateThread(RichTextBox RTB, string path)
  27.     {
  28.         Action action2 = () => RTB.Text += DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss.fff", CultureInfo.InvariantCulture) + "\t";
  29.         if (RTB.InvokeRequired)
  30.         {
  31.             RTB.Invoke(action2);
  32.         }
  33.         else
  34.         {
  35.             action2();
  36.         }
  38.         List<string> resultLog = new List<string>();
  39.         Stopwatch stopwatch = new Stopwatch();
  40.         stopwatch.Start();
  41.         resultLog.Add(GetFileName(path) + " {" + string.Join(", ", CountBytes(path)) + " } ");
  42.         stopwatch.Stop();
  43.         resultLog.Add(stopwatch.ElapsedMilliseconds.ToString() + " ms");
  45.         if (RTB.InvokeRequired)
  46.         {
  47.             RTB.BeginInvoke((MethodInvoker)(() =>
  48.             {
  49.                 RTB.Text += String.Join("", resultLog) + ''\n'';
  50.             }
  51.             ));
  52.         }
  53.         else
  54.         {
  55.             RTB.Text += String.Join("", resultLog) + ''\n'';
  56.         }
  57.     }
  59.     private string GetFileName(string path)
  60.     {
  61.         return System.IO.Path.GetFileName(path);
  62.     }
  64.     private ulong[] CountBytes(string filename)
  65.     {
  66.         ulong[] Bytes = new ulong[256];
  68.         byte[] buffer = new byte[4096 * 1000];
  69.         int bytesRead = 0;
  70.         using (FileStream reader = File.OpenRead(filename))
  71.             while ((bytesRead = reader.Read(buffer, 0, buffer.Length)) > 0)
  72.                 for (int i = 0; i < bytesRead; Bytes[buffer[i++]]++) ;
  74.         return Bytes;
  75.     }
  76. }

请告诉我如果您需要任何额外的帮助。

英文:

My application processes the directory (each file in a separate thread) and displays information on the screen as it runs (I use richtextbox).

There is my code:

  1. class FilesHandler
  2. {
  3. private List<string> PathesOfFiles = new List<string>();
  4. public void LoadPathes(string pathOfDirectory)
  5. {
  6. string[] allfiles = Directory.GetFiles(pathOfDirectory);
  7. foreach (string filename in allfiles)
  8. {
  9. PathesOfFiles.Add(filename);
  10. }
  11. }
  12. public void HandleEachFile(RichTextBox RTB)
  13. {
  14. foreach (string path in PathesOfFiles)
  15. {
  16. new Thread(() => { CalculateThread(RTB, path); }).Start();
  17. }
  18. }
  19. private void CalculateThread(RichTextBox RTB, string path)
  20. {
  21. Action action2 = () => RTB.Text += DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss.fff", CultureInfo.InvariantCulture) + "\t";
  22. if (RTB.InvokeRequired)
  23. {
  24. RTB.Invoke(action2);
  25. }
  26. else
  27. {
  28. action2();
  29. }
  30. List<string> resultLog = new List<string>();
  31. Stopwatch stopwatch = new Stopwatch();
  32. stopwatch.Start();
  33. resultLog.Add(GetFileName(path) + " {" + string.Join(", ", CountBytes(path)) + " } ");
  34. stopwatch.Stop();
  35. resultLog.Add(stopwatch.ElapsedMilliseconds.ToString() + " ms");
  36. if (RTB.InvokeRequired)
  37. {
  38. RTB.BeginInvoke((MethodInvoker)(() =>
  39. {
  40. RTB.Text += String.Join("", resultLog) + '\n';
  41. }
  42. ));
  43. }
  44. else
  45. {
  46. RTB.Text += String.Join("", resultLog) + '\n';
  47. }
  48. }
  49. private string GetFileName(string path)
  50. {
  51. return System.IO.Path.GetFileName(path);
  52. }
  53. private ulong[] CountBytes(string filename)
  54. {
  55. ulong[] Bytes = new ulong[256];
  56. byte[] buffer = new byte[4096 * 1000];
  57. int bytesRead = 0;
  58. using (FileStream reader = File.OpenRead(filename))
  59. while ((bytesRead = reader.Read(buffer, 0, buffer.Length)) > 0)
  60. for (int i = 0; i < bytesRead; Bytes[buffer[i++]]++) ;
  61. return Bytes;
  62. }
  63. }

I've been doing the output in each thread using Control.Invoke, but my mentor told me to make a callback, but I don't understand how to do it, since I haven't worked with it before.
Thanks!!!

答案1

得分: 0

不必使用 InvokeRequired。

而是使用更现代的方法，如 Progress<T> 来返回进度状态给用户界面，和/或使用 await 来将你带回用户界面线程。

将 CountBytes 交给线程池线程使用 Task.Run，以避免阻塞循环的其余部分。

另外：

  • 使用 EnumerateFiles 替代 GetFiles，并使用 AddRange 替代循环。
  • 使用 List<ulong> 存储接收到的字节数。
  1. class FilesHandler
  2. {
  3.     private List<string> PathesOfFiles = new List<string>();
  5.     public void LoadPathes(string pathOfDirectory)
  6.     {
  7.         PathesOfFiles.AddRange(Directory.EnumerateFiles(pathOfDirectory));
  8.     }
  10.     public void HandleEachFile(IProgress<string> progress)
  11.     {
  12.         foreach (string path in PathesOfFiles)
  13.         {
  14.             Task.Run(() => CalculateThread(progress, path));
  15.         }
  16.     }
  18.     private async Task CalculateThread(IProgress<string> progress, string path)
  19.     {
  20.         progress.Report(DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss.fff", CultureInfo.InvariantCulture) + "\t");
  22.         Stopwatch stopwatch = Stopwatch.StartNew();
  23.         var bytes = await CountBytes(path);
  24.         stopwatch.Stop();
  26.         progress.Report(Path.GetFileName(path) + " {" + string.Join(", ", bytes) + " } ");
  27.         progress.Report(stopwatch.ElapsedMilliseconds.ToString() + " ms");
  28.     }
  30.     private async Task<List<ulong>> CountBytes(string filename)
  31.     {
  32.         List<ulong> allBytesRead = new List<ulong>(256);
  34.         byte[] buffer = new byte[4096 * 1000];
  35.         int bytesRead = 0;
  36.         using (FileStream reader = File.OpenRead(filename))
  37.             while ((bytesRead = await reader.ReadAsync(buffer, 0, buffer.Length)) > 0)
  38.                 for (int i = 0; i < bytesRead; allBytesRead.Add(buffer[i++]));
  40.         return allBytesRead;
  41.     }
  42. }

现在你可以简单地执行以下操作：

  1. HandleEachFile(new Progress<string>(str => RTB.Text += str));

请注意，显然有更好的方法来获取文件中的所有字节，我假设这是一个练习。

英文:

Don't bother with InvokeRequired.

Instead use more modern methods such as a Progress&lt;T&gt; to return progress status to the UI, and/or await to get you back on to the UI thread.

Hand off CountBytes to a threadpool thread using Task.Run in order not to block the rest of the loop.

Also:

  • Use EnumerateFiles instead of GetFiles, and AddRange instead of looping.
  • Use a List&lt;ulong&gt; for the counts of bytes received.
  1. class FilesHandler
  2. {
  3.     private List&lt;string&gt; PathesOfFiles = new List&lt;string&gt;();
  5.     public void LoadPathes(string pathOfDirectory)
  6.     {
  7.         PathesOfFiles.AddRange(Directory.EnumerateFiles(pathOfDirectory))
  8.     }
  10.     public void HandleEachFile(IProgress&lt;string&gt; progress)
  11.     {
  12.         foreach (string path in PathesOfFiles)
  13.         {
  14.             Task.Run(() =&gt; CalculateThread(progress, path));
  15.         }
  16.     }
  18.     private async Task CalculateThread(IProgress&lt;string&gt; progress, string path)
  19.     {
  20.        progress.Report(DateTime.UtcNow.ToString(&quot;yyyy-MM-dd HH:mm:ss.fff&quot;, CultureInfo.InvariantCulture) + &quot;\t&quot;);
  22.         Stopwatch stopwatch = Stopwatch.StartNew();
  23.         var bytes = await CountBytes(path);
  24.         stopwatch.Stop();
  26.         progress.Report((Path.GetFileName(path) + &quot; {&quot; + string.Join(&quot;, &quot;, bytes) + &quot; } &quot;);
  27.         progress.Report((stopwatch.ElapsedMilliseconds.ToString() + &quot; ms&quot;);
  28.     }
  30.     private async Task&lt;List&lt;ulong&gt;&gt; CountBytes(string filename)
  31.     {
  32.         List&lt;ulong&gt; allBytesRead = new(256);
  34.         byte[] buffer = new byte[4096 * 1000];
  35.         int bytesRead = 0;
  36.         using (FileStream reader = File.OpenRead(filename))
  37.             while ((bytesRead = await reader.ReadAsync(buffer, 0, buffer.Length)) &gt; 0)
  38.                 for (int i = 0; i &lt; bytesRead; allBytesRead.Add(buffer[i++]);
  40.         return allBytesRead;
  41.     }
  42. }

You can now simply do

  1. HandleEachFile(new Progress&lt;string&gt;(str =&gt; RTB.Text += str);

Note that there are obviously much better ways to get all the bytes in a file, I assume this is for an exercise.

huangapple
  • 本文由 发表于 2023年8月4日 20:56:36
  • 转载请务必保留本文链接：https://go.coder-hub.com/76836126.html
  • .net
  • c#
  • winforms
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