UI冻结和计算真的很慢

Question

我正在编写一个程序，它应该替换或删除logfile.txt中的一些条目。 代码工作正常（至少对于小型LogFiles）。如果我使用大文件（例如27 MB），它会变得非常缓慢并且UI冻结。我不能点击任何东西。

在按钮点击我执行此方法：

 private string delete_Lines(string[] lines, string searchString) 
    { 

     for (int i = 0; i < lines.Length; i++) 
     { 

      if (lines[i].Contains(searchString)) 
      { 
       rtbLog.Text += "Deleting(row " + (i + 1) + "):\n" + lines[i] + "\n"; 
       progressBar1.Value += 1; 
       if (cbDB == true) 
       { 
        while (is_next_line_block(lines, i) == true) 
        { 
         i++; 
         rtbLog.Text += lines[i] + "\n"; 
         progressBar1.Value += 1; 
        } 
       } 

      } 
      else 
      { 
       res += lines[i]+"\n"; 
       progressBar1.Value += 1; 
      } 

     } 
     tssLbl.Text = "Done!"; 
     rtbLog.Text += "...Deleting finished\n"; 
     return res; 
    } 

行是日志文件我试图清理的阵列。每个条目都是单行。 tssLbl是一个通知标签，rtbLog是一个richTextBox，我跟踪哪一行正在删除。

is_next_line_block是另一种方法，它是检查下一行是我想要删除的块的一部分。这种方法的参数是整行数组和行位置。

private bool is_next_line_block(string[] lines, int curIndex) 
    { 
     if (curIndex < lines.Length-1) 
     { 
      if (lines[curIndex + 1].StartsWith(" ")) 
      { 
       return true; 
      } 
      else 
      { 
       return false; 
      } 
     } 
     else 
     { 
      return false; 
     } 

    } 

有没有人有任何想法，是什么导致冻结，并在减慢程序？我知道，我可以通过并行化来加速我的代码，但我无法想象，检查没有并行性的27 MB txt文件需要很长时间。

Answer 1

您在这里有几个问题：

1. 您正在阅读缓冲整个文件（字符串数组），我猜你在呼唤File.ReadAllLines（）。在缓冲区中读取大文件会减慢你的速度，并且在极端的情况下会让你失去内存。

2. 您正在为富文本框Text属性使用+ =操作。这是非常耗时的操作，因为每次以这种方式更新文本属性时，UI必须呈现整个富文本框。更好的选择是使用字符串生成器来加载这些文本，并定期更新富文本框。

要解决此问题，您需要将文件读取为流。可以根据读取的字节而不是行位置来监视进度。您可以运行读取操作异步并监视计时器的进度，如下例所示。

private void RunFileOperation(string inputFile, string search) 
{ 
    Timer t = new Timer(); 
    int progress = 0; 
    StringBuilder sb = new StringBuilder(); 

    // Filesize serves as max value to check progress 
    progressBar1.Maximum = (int)(new FileInfo(inputFile).Length); 
    t.Tick += (s, e) => 
     { 
      rtbLog.Text = sb.ToString(); 
      progressBar1.Value = progress; 
      if (progress == progressBar1.Maximum) 
      { 
       t.Enabled = false; 
       tssLbl.Text = "done"; 
      } 
     }; 
    //update every 0.5 second  
    t.Interval = 500; 
    t.Enabled = true; 
    // Start async file read operation 
    System.Threading.Tasks.Task.Factory.StartNew(() => delete_Lines(inputFile, search, ref progress, ref sb));  
} 

private void delete_Lines(string fileName, string searchString, ref int progress, ref StringBuilder sb) 
{ 
    using (var file = File.OpenText(fileName)) 
    { 
     int i = 0; 
     while (!file.EndOfStream) 
     { 
      var line = file.ReadLine(); 
      progress = (int)file.BaseStream.Position; 
      if (line.Contains(searchString)) 
      { 
       sb.AppendFormat("Deleting(row {0}):\n{1}", (i + 1), line); 
       // Change this algorithm for nextline check 
       // Do this when it is next line, i.e. in this line. 
       // "If" check above can check if (line.startswith(" "))... 
       // instead of having to do it nextline next here. 
       /*if (cbDB == true) 
       { 
        while (is_next_line_block(lines, i) == true) 
        { 
         i++; 
         rtbLog.Text += lines[i] + "\n"; 
         progressBar1.Value += 1; 
        } 
       }*/ 
      } 
     } 
    }   
    sb.AppendLine("...Deleting finished\n"); 
} 

Answer 2

作为后续行动上Task.Factory.Start()使用你的问题，它的完成这种方式（一般）：

// you might need to wrap this in a Dispatcher.BeginInvoke (see below) 
// if you are not calling from the main UI thread 
CallSomeMethodToSetVisualCuesIfYouHaveOne(); 

Task.Factory.StartNew(() => 
{ 
    // code in this block will run in a background thread... 
} 
.ContinueWith(task => 
{ 
    // if you called the task from the UI thread, you're probably 
    // ok if you decide not to wrap the optional method call below 
    // in a dispatcher begininvoke... 
    Application.Current.Dispatcher.BeginInvoke(new Action(()=> 
    { 
     CallSomeMethodToUnsetYourVisualCuesIfYouHaveAnyLOL(); 
    })); 
} 

希望这有助于！

Answer 3

感谢大家的帮助，尤其是loopedcode，这就是工作版本（拿了loopedcode的代码，并提出了一些修改）：

 private void RunFileOperation(string inputFile, string search) 
    { 
     Timer t = new Timer(); 
     StringBuilder sb = new StringBuilder(); 
     { 
      rtbLog.Text = "Start Deleting...\n"; 
     } 


     // Filesize serves as max value to check progress 
     progressBar1.Maximum = (int)(new FileInfo(inputFile).Length); 
     t.Tick += (s, e) => 
     { 
      rtbLog.Text += sb.ToString(); 
      progressBar1.Value = progress; 
      if (progress == progressBar1.Maximum) 
      { 
       t.Enabled = false; 
       tssLbl.Text = "done"; 
      } 
     }; 
     //update every 0.5 second  
     t.Interval = 500; 
     t.Enabled = true; 
     // Start async file read operation 
     if (rbtnDelete.Checked) 
     { 
      if (cbDelete.Checked) 
      { 
       System.Threading.Tasks.Task.Factory.StartNew(() => delete_Lines(inputFile, search, ref progress, ref sb, ref res1)); 
      } 
    } 
    else 
    { 
     //..do something 
    } 

    private void delete_Lines(string fileName, string searchString, ref int progress, ref  StringBuilder sb, ref StringBuilder res1) 
    { 
    bool checkNextLine=false; 
     using (var file = File.OpenText(fileName)) 
     { 
      int i = 0; 
      while (!file.EndOfStream) 
      { 
       i++; 
       var line = file.ReadLine(); 
       progress = (int)file.BaseStream.Position; 
       if (line.Contains(searchString)) 
       { 
        sb.AppendFormat("Deleting(row {0}):\n{1}\n", (i), line); 
        checkNextLine = true; 
       } 
       else 
       { 
        if (cbDB && checkNextLine && line.StartsWith(" ")) 
        { 
         sb.AppendFormat("{0}\n", line); 
        } 
        else 
        { 
         checkNextLine = false; 
         res1.AppendLine(line); 

        } 
       } 

      } 
     } 
     sb.AppendLine("\n...Deleting finished!); 
    }