啟動新實例時如何獲取ID進程？

Question

我正在嘗試啟動 Firefox 並在幾秒鍾后將其關閉。 我的代碼是這樣的：

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}");
}

然后問題是當我在taskkill進程中設置斷點時，任務管理器中不存在myProcess.Id。 Firefox 的所有實例都有另一個 ID。

如果我嘗試打開記事本，它可以工作，記事本的 ID 是 myProcess 的 ID。

所以我在想，也許用 Firefox 打開一個進程，然后關閉它，然后打開另一個 Firefox 實例。 這是真的？

怎么知道 firefox 的 ID？ 或者我怎么能殺死 Firefox 的所有進程？ 因為其實我的Firefox進程不止一個，我有很多。

謝謝。

Answer 1

使用Task.Delay(...)時，您應該await它，否則您將開始一個新任務並立即忘記它：

您的代碼已修改：

//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}")) {}
  }

代碼：（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();
      }
    }
  }