System.Diagnostics.Process RedirectStandardOutput問題實時顯示在Winforms文本框中

Question

我在實時從Winforms文本框中顯示控制台應用程序的重定向輸出時遇到問題。 消息是逐行生成的，但是，一旦要求與表單進行交互，就不會顯示任何內容。

遵循Stackoverflow和其他論壇上的許多示例之后，在過程完成之前，我似乎無法從過程中獲取重定向的輸出以顯示在表單的文本框中。

通過將調試行添加到'stringWriter_StringWritten'方法並將重定向消息寫入調試窗口，我可以看到在過程運行期間到達的消息，但是這些消息將在過程完成之前不會出現在表單的文本框中。

感謝對此的任何建議。

這是代碼的一部分

public partial class RunExternalProcess : Form
{
    private static int numberOutputLines = 0;
    private static MyStringWriter stringWriter;

    public RunExternalProcess()
    {
        InitializeComponent();

        // Create the output message writter
        RunExternalProcess.stringWriter = new MyStringWriter();
        stringWriter.StringWritten += new EventHandler(stringWriter_StringWritten);

        System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo();

        startInfo.FileName = "myCommandLineApp.exe";

        startInfo.UseShellExecute = false;
        startInfo.RedirectStandardOutput = true;
        startInfo.CreateNoWindow = true;
        startInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;

        using (var pProcess = new System.Diagnostics.Process())
        {
            pProcess.StartInfo = startInfo;
            pProcess.OutputDataReceived += new System.Diagnostics.DataReceivedEventHandler(RunExternalProcess.Process_OutputDataReceived);
            pProcess.EnableRaisingEvents = true;

            try
            {
                pProcess.Start();

                pProcess.BeginOutputReadLine();
                pProcess.BeginErrorReadLine();

                pProcess.WaitForExit();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
            finally
            {
                pProcess.OutputDataReceived -= new System.Diagnostics.DataReceivedEventHandler(RunExternalProcess.Process_OutputDataReceived);
            }
        }
    }

    private static void Process_OutputDataReceived(object sender, System.Diagnostics.DataReceivedEventArgs e)
    {
        if (!string.IsNullOrEmpty(e.Data))
        {
            RunExternalProcess.OutputMessage(e.Data);
        }
    }

    private static void OutputMessage(string message)
    {
        RunExternalProcess.stringWriter.WriteLine("[" + RunExternalProcess.numberOutputLines++.ToString() + "] - " + message);
    }

    private void stringWriter_StringWritten(object sender, EventArgs e)
    {
        System.Diagnostics.Debug.WriteLine(((MyStringWriter)sender).GetStringBuilder().ToString());

        SetProgressTextBox(((MyStringWriter)sender).GetStringBuilder().ToString());
    }

    private delegate void SetProgressTextBoxCallback(string text);

    private void SetProgressTextBox(string text)
    {
        if (this.ProgressTextBox.InvokeRequired)
        {
            SetProgressTextBoxCallback callback = new SetProgressTextBoxCallback(SetProgressTextBox);
            this.BeginInvoke(callback, new object[] { text });
        }
        else
        {
            this.ProgressTextBox.Text = text;
            this.ProgressTextBox.Select(this.ProgressTextBox.Text.Length, 0);
            this.ProgressTextBox.ScrollToCaret();
        }
    }
}

public class MyStringWriter : System.IO.StringWriter
{
    // Define the event.
    public event EventHandler StringWritten;

    public MyStringWriter()
        : base()
    {
    }

    public MyStringWriter(StringBuilder sb)
        : base(sb)
    {
    }

    public MyStringWriter(StringBuilder sb, IFormatProvider formatProvider)
        : base(sb, formatProvider)
    {
    }

    public MyStringWriter(IFormatProvider formatProvider)
        : base(formatProvider)
    {
    }

    protected virtual void OnStringWritten()
    {
        if (StringWritten != null)
        {
            StringWritten(this, EventArgs.Empty);
        }
    }

    public override void Write(char value)
    {
        base.Write(value);
        this.OnStringWritten();
    }

    public override void Write(char[] buffer, int index, int count)
    {
        base.Write(buffer, index, count);
        this.OnStringWritten();
    }

    public override void Write(string value)
    {
        base.Write(value);
        this.OnStringWritten();
    }
}

Answer 1

   pProcess.WaitForExit();

您正在用它掛UI線程。 在該過程退出之前，它不會像漆文本框那樣正常工作。 同樣，在UI線程再次變為空閑之前，BeginInvoke（）委托目標無法運行。 它們將堆積在調用隊列中，在極端情況下，您將耗盡內存。 即使在進程退出后，UI線程在清空隊列時也會在一段時間內無響應。

您在這里不需要它。 如有必要，請改用Process.Exited事件。