启动新实例时如何获取ID进程？

Question

我正在尝试启动 Firefox 并在几秒钟后将其关闭。 我的代码是这样的：

using (Process myProcess = new Process())
{
    myProcess.StartInfo.UseShellExecute = false;
    myProcess.StartInfo.FileName = @"C:\Program Files\Mozilla Firefox\firefox.exe";
    myProcess.StartInfo.CreateNoWindow = false;
    myProcess.Start();

    Task.Delay(5000);


    Process.Start("taskkill.exe", $"/PID {myProcess.Id}");
}

然后问题是当我在taskkill进程中设置断点时，任务管理器中不存在myProcess.Id。 Firefox 的所有实例都有另一个 ID。

如果我尝试打开记事本，它可以工作，记事本的 ID 是 myProcess 的 ID。

所以我在想，也许用 Firefox 打开一个进程，然后关闭它，然后打开另一个 Firefox 实例。 这是真的？

怎么知道 firefox 的 ID？ 或者我怎么能杀死 Firefox 的所有进程？ 因为其实我的Firefox进程不止一个，我有很多。

谢谢。

Answer 1

使用Task.Delay(...)时，您应该await它，否则您将开始一个新任务并立即忘记它：

您的代码已修改：

//TODO: check if your method is declared as async
private async Task MyMethod() {

  ...

  using (Process myProcess = new Process()) {
    myProcess.StartInfo.UseShellExecute = false;
    myProcess.StartInfo.FileName = @"C:\Program Files\Mozilla Firefox\firefox.exe";
    myProcess.StartInfo.CreateNoWindow = false;
    myProcess.Start();

    // await for 5 seconds delay
    await Task.Delay(5000);

    // this will be continued after 5 seconds delay 
    // Do not forget to dispose yet another process - taskkill.exe
    // Why not myProcess.Kill(); ?
    using (Process.Start("taskkill.exe", $"/PID {myProcess.Id}")) {}
  }

代码：（我的版本）

//TODO: check if your method is declared as async
private async Task MyMethod() {
  ...
  
  // Let's extract model (how to start process) from execution
  ProcessStartInfo psi = new ProcessStartInfo() {
    UseShellExecute = false,
    FileName = @"C:\Program Files\Mozilla Firefox\firefox.exe",
    CreateNoWindow = false,
  };

  // Process.Start can return null, which we forgive with !
  using (Process myProcess = Process.Start(psi)!) {
    // We, typically, cancel Tasks instead of delaying and analyzing 
    using (CancellationTokenSource cts = new CancellationTokenSource(5000)) {
      try {
        // start process with cancellation after 5 seconds 
        await myProcess!.WaitForExitAsync(cts.Token);
      }
      catch (TaskCanceledException) {
        // if process has been cancelled (not completed) we want to kill it
        myProcess!.Kill();
      }
    }
  }