在 Task.Run 中运行时未达到 Process.Exited

Question

当我在 WPF 应用程序中使用 Task.Run 运行进程时，我遇到了让 Process.Exited 事件触发的问题。 如果由于流程类限制而无法获得此 Exited 事件，我想在任务完成后更新 TextBox.Text。 我尝试了 ContinueWith 也没有任何运气

async private void Select_Click(object sender, RoutedEventArgs e)
    {
        CancellationToken ct = new CancellationToken();
        CancellationTokenSource cts = new CancellationTokenSource();

        FolderBrowserDialog diag;
        TaskCompletionSource<object> tcs = new TaskCompletionSource<object>();
        Notification.Text = string.Empty;
        diag = new FolderBrowserDialog();
        var result = diag.ShowDialog();
        var istest = TestMode.IsChecked == true;

        if (result == System.Windows.Forms.DialogResult.OK)
        {
            var path = diag.SelectedPath;
            await Task.Run(() =>
            {
                var processStartInfo = new ProcessStartInfo()
                                {
                                    FileName = "cmd.exe",
                                    WindowStyle = ProcessWindowStyle.Hidden,
                                    RedirectStandardOutput = true,
                                    RedirectStandardError = true,
                                    RedirectStandardInput = true,
                                    UseShellExecute = false,
                                    CreateNoWindow = true
                                };
                var command="ping yahoo.com";

                var process = new Process() { StartInfo = processStartInfo, EnableRaisingEvents = true };
                process.Start();

                process.BeginOutputReadLine();
                process.BeginErrorReadLine();
                process.StandardInput.WriteLineAsync(command);
                process.ErrorDataReceived += (p, @event) =>
                {
                    Dispatcher.InvokeAsync(() =>
                    {
                        Notification.AppendText(String.Format("Error {0} {1}", @event.Data, Environment.NewLine));
                    }, System.Windows.Threading.DispatcherPriority.Background);
                };
                process.OutputDataReceived += (p, @event) =>
                {
                    Dispatcher.InvokeAsync(() =>
                    {
                        Notification.AppendText(@event.Data + Environment.NewLine);
                    }, System.Windows.Threading.DispatcherPriority.Background);
                };
                process.WaitForExit();
                process.Exited += (@Sender, args) =>
                {
                    tcs.SetResult(process);
                    System.Windows.MessageBox.Show("Done");
                    process.Dispose();
                };
            });

        }

    }

所有其他事件都被触发，没有任何问题。 谢谢

Answer 1

在订阅Exited 事件之前调用WaitForExit，因此线程将在那里等待直到进程退出，并且在进程退出之前永远不会订阅事件。当WaitForExit返回过程已经退出时，那么只有你订阅Exited事件，它永远不会再次触发。

所以在调用WaitForExit之前订阅Exited事件。

process.Exited += (@Sender, args) =>
{
    tcs.SetResult(process);
    System.Windows.MessageBox.Show("Done");
    process.Dispose();
};
process.WaitForExit();