c# - visual C# 是否有可能比进程运行的进度条有更多的反馈？

Question

我正在使用 Microsoft Visual Studio(Windows 窗体)在 C# 中开发应用程序。我想做的是通过一个 GUI 管理不同的环境。

因此，我的图形用户界面必须异步启动一些进程(这是命令行应用程序)。问题是我只能在进程完成后获得标准输出，这意味着我无法显示进程在运行时正在做什么。因为我要运行的应用程序可能需要相当长的运行时间(上传大文件......)我想在运行时显示过程输出。

因此，我创建了一个 backgroundworker 来将我的 gui 与进程分开，并且我尝试使用一个临时文件来写入进程输出。然后使用 FileSystemWatcher，我可以使用“更改”事件在我的 GUI 中显示消息。

我的问题是，由于临时文件是打开写入的，我无法同时从中读取。这是我的代码，有没有人有办法绕过这个问题？还是其他方式？

 public partial class Form1 : Form
{

    Boolean done = false;
    private FileSystemWatcher observateur;

    public Form1()
    {
        InitializeComponent();

        // delete the temporary file if existing
        if (System.IO.File.Exists("C:\\testoutput.txt"))
        {
            try
            {
                System.IO.File.Delete("C:\\testoutput.txt");
            }
            catch (System.IO.IOException exept)
            {
                Console.WriteLine(exept.Message);
                return;
            }
        }
        File.Create("C:\\testoutput.txt");

        backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler
                (backgroundWorker1_ProgressChanged);
        observateur = new FileSystemWatcher();
        observateur.Filter = "C:\\testoutput.txt";  
        observateur.Changed += new FileSystemEventHandler(this.OnChanged);
        observateur.Created += new FileSystemEventHandler(this.OnCreate);
    }

    private void OnChanged(object source, FileSystemEventArgs e)
    {
        // I tried to bypass the problem of having the file opened by copying it but i doesn't work
        File.Copy("C:\\testouput.txt", "C:\\TEMP.txt", true);
    }

    private void OnCreate(object source, FileSystemEventArgs e)
    {
        Console.WriteLine("Created");
    }

    private void button3_Click(object sender, EventArgs e)
    {
        string outputworker = "";
        backgroundWorker1.RunWorkerAsync(outputworker);

        while (!done)
        {
            string text = System.IO.File.ReadAllText("C:\\TEMP.txt");
            Thread.Sleep(200);
        }
    }

    void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        progressBar1.Value = e.ProgressPercentage;
        outputTextArea.Text = "Processing......" + progressBar1.Value.ToString() + "%";
    }



    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        string[] args = { "/k " };
        string outputWork = e.Argument as string;
        backgroundWorker1.ReportProgress(10);

        System.Diagnostics.Process process = new System.Diagnostics.Process();
        process.StartInfo.WorkingDirectory = "C:\\XXXXXXXXXX";
        process.StartInfo.UseShellExecute = false;
        process.StartInfo.FileName = "cmd.exe";
        int nArgs = args.Length;
        if (nArgs > 0)
        {
            process.StartInfo.Arguments = args[0];
        }
        for (int i = 1; i < nArgs; i++)
        {
            process.StartInfo.Arguments = String.Concat(process.StartInfo.Arguments, " && ", args[i]);
        }
        process.StartInfo.CreateNoWindow = true;
        process.StartInfo.RedirectStandardInput = true;
        process.StartInfo.RedirectStandardOutput = true;
        process.StartInfo.RedirectStandardError = true;

        backgroundWorker1.ReportProgress(20);
        process.Start();


        backgroundWorker1.ReportProgress(40);
        System.IO.StreamWriter sIn = process.StandardInput;

        sIn.WriteLine("ExternalCommandLineApp1.exe >> C:\\testoutput.txt");
        backgroundWorker1.ReportProgress(60);
        sIn.WriteLine("ExternalCommandLineApp1.exe >> C:\\testoutput.txt");

        System.IO.StreamReader sOut = process.StandardOutput;
        backgroundWorker1.ReportProgress(90);

        sIn.WriteLine("EXIT");

        outputWork = sOut.ReadToEnd();

        process.Close();
        backgroundWorker1.ReportProgress(100);

        e.Result = outputWork;
        done = true;
    }

    private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        string output = e.Result as string;
        //outputTextArea.Text = output;
    }
}

Answer 1

这不是其他答案中提到的最佳方式，但它仍然可以成功运行。

您可以打开文件进行读/写，而不会阻止其他读/写。只需使用 File.Open 而不是辅助方法并提供额外的参数(FileMode 和 FileShare)这是一个完整的例子。请注意，一个线程保持文件打开以进行写入，第二个线程每次打开和关闭文件并读取所有行:

using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string fileName = "c:\\_data\\temp.txt";

            Task writer = new Task(() => {

                using (FileStream fs = File.Open(fileName, FileMode.OpenOrCreate, FileAccess.Write, FileShare.ReadWrite))
                using (StreamWriter sw = new StreamWriter(fs))
                {
                    for (int i = 0; i < 50; i++ )
                    {
                        sw.WriteLine(DateTime.Now.Millisecond.ToString());
                        sw.Flush();
                        Thread.Sleep(500);
                    }
                }


            });

            Task reader = new Task(() => {
                for (int i = 0; i < 50; i++)
                {
                    Thread.Sleep(500);
                    Console.WriteLine("Read again");
                    if (File.Exists(fileName))
                    {
                        using (FileStream fs = File.Open(fileName, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))
                        using (StreamReader r = new StreamReader(fs))
                        {
                            while (!r.EndOfStream)
                            {
                                Console.WriteLine(r.ReadLine());
                            }
                        }
                    }
                }
            });

            writer.Start();
            reader.Start();

            writer.Wait();
            reader.Wait();
        }
    }
}