如何创建一个可以等待多个进程退出的函数？

Question

我正在创建一个Windows服务，它将为我想要监视的特定进程写入所有开始时间和退出时间。问题是当我试图监视进程等待退出时，我不知道如何等待多个进程退出。下面是我编写流程开始时间的代码。

Try
    Using regkey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64).OpenSubKey("SOFTWARE\MonitoringApplication\Login", RegistryKeyPermissionCheck.Default)
        childrenID = regkey.GetValue("Login User").ToString
    End Using
    If childrenID.Equals("admin") Then
    Else
        Dim connection As New SqlConnection("Server=DESKTOP-FTJ3EOA\SQLEXPRESS;Initial Catalog=MonitorDB;User ID = admin; Password = admin")
        Dim command As New SqlCommand("SELECT  App.ApplicationName FROM App INNER JOIN ChildrenApplication ON App.ApplicationID = ChildrenApplication.ApplicationID WHERE ChildrenID = @a", connection)
        command.Parameters.Add("@a", SqlDbType.VarChar).Value = childrenID
        Dim adapter As New SqlDataAdapter(command)
        Dim table As New DataTable()
        adapter.Fill(table)

        Using sw As StreamWriter = New StreamWriter(AppDomain.CurrentDomain.BaseDirectory + "\MonitoringApplication.txt", True)

            For Each row As DataRow In table.Rows
                p = Process.GetProcessesByName(row.Item(0))
                Using myprocess = New Process
                    If p.Count > 0 Then
                        myprocess.StartInfo.FileName = row.Item(0)
                        myprocess.EnableRaisingEvents = True
                        sw.WriteLine(row.Item(0) + "running")

                    End If
                End Using
            Next row
        End Using

        Const SLEEP_AMOUNT As Integer = 100
        Do While Not eventHandled
            elapsedTime += SLEEP_AMOUNT
            If elapsedTime > 30000 Then
                Exit Do
            End If
            Thread.Sleep(SLEEP_AMOUNT)
        Loop
    End If
Catch ex As Exception
    Using sw As StreamWriter = New StreamWriter(AppDomain.CurrentDomain.BaseDirectory + "\MonitoringApplication.txt", True)
        sw.WriteLine(ex)
    End Using
End Try

Private Sub myProcess_Exited(ByVal sender As Object, ByVal e As System.EventArgs) Handles myProcess.Exited
    eventHandled = True
    Using sw As StreamWriter = New StreamWriter(AppDomain.CurrentDomain.BaseDirectory + "\MonitoringApplication.txt", True)
        sw.WriteLine("Exited")
    End Using
End Sub

有没有办法监控多个进程退出？提前致谢。

Answer 1

您现在正在使用Process.GetProcessesByName()来检索正在运行的进程数组（如果有）。 您可以使用返回的进程数组并订阅每个进程的Exited事件来记录数组中任何进程的退出时间。

设置EnableRaisingEvent是提升Exited事件所必需的，但你还需要使用AddHandler以及方法或Lambda的地址订阅事件：

AddHandler [Process].Exited, AddressOf [Handler]
' or 
AddHandler [Process].Exited, Sub() [Lambda]

此方法接受进程名称和文件的路径，以便在引发Exited事件时存储进程名称及其退出时间。

如果您当前循环：

For Each row As DataRow In table.Rows
    '(...)
Next

您可以插入对此方法的调用：

For Each row As DataRow In table.Rows
    SubscribeProcExit(row.Item(0), Path.Combine(Application.StartupPath, "MonitoringApplication.txt"))
Next

如果日志文件没有退出，那么每次进程退出时都会创建并添加一个新行，记录Process.ProcessName和Process.ExitTime。 请注意，row.Item(0)必须包含Process的友好名称。例如，notepad.exe必须被引用为"notepad"。

Private Sub SubscribeProcExit(processName As String, fileName As String)
    Dim processes As Process() = Process.GetProcessesByName(processName)
    If processes.Length = 0 Then Return
    For Each p As Process In processes
        p.EnableRaisingEvents = True
        AddHandler p.Exited,
            Sub()
                Using sw As StreamWriter = File.AppendText(fileName)
                    sw.WriteLine($"Process: {p?.ProcessName}, Exit Time: {p?.ExitTime}")
                    p?.Dispose()
                End Using
            End Sub
    Next
End Sub