假如要启动 this.exe。以下逻辑中会启动先后关联启动三个实例分别是ABC。先启动第一个实例A，A启动实例B，B启动实例C.
要求：
1.如果没有以管理员权限运行，则请求管理员权限运行，即使没有请求成功或请求成功之前，也要先以非管理员权限运行，因为它定时要执行一些任务，不能因阻塞而错过。
2.如果没有以管理员权限运行，也要可以动态申请以管理员权限来注册开机启动，然后托盘显示右键菜单指示是否已经设置开机启动。
3.支持Windows XP 到 Windows 10.
4.自启过程无需人工干预，全自动无阻塞。
5.不能关闭UAC，如果这个都关了，我们就不用讨论了。
要实现以上3点，其实并不容易，XP容易实现自不必说，从Vista开始就不那么容易了。
有两个难点：
1. 以管理员身份开机自启。注册表实现不了，启动菜单目录也实现不了。因为即使设置了程序的兼容性以管理员身份运行，但弹出的那个UAC确认框谁来点呢？据我所知，用计划任务是目前唯一可以实现以管理员身份启动并且不需要UAC确认的。
2. 当以非管理员身份运行时，动态申请管理员权限，当然这个是需要UAC确认的。
用来做一些人工设置的时候，这时候人是在电脑旁边的。比如设置开机自启，取消开机自启。
这个解决方案比较简单，实例A用RunAs方式申请管理员权限启动一个新实例B，传入命令行参数，B执行完自动结束。即使申请启动失败，A也可以继续存活，想要申请过程无阻塞就新开一个线程来做。
但有一个问题，B有没有启动成功？用户有没有在UAC确认时允许？即使是用户确认了，B成功在计划任务创建了开机以管理员身份启动。但是A依然无法判断是否成功设置了开机自启，托盘无法正确的为用户指示开机自启状态。有人会说查询一下计划任务里有没有我们创建的任务就行了，很可惜，因为A没有管理员权限，所以无法查询。
我其实也搞不懂，微软为什么查询计划任务都需要管理员权限。
既然B都有管理员权限了，它返回一个ExitCode不就行了。当然这样可以，但是开机自启是敏感操作，很可能被杀软干掉，这样我们的开机自启状态指示就变得不可靠。
有一个办法，Ｂ既然已经有了管理员权限，让它启动一个C，C就是一个完全有管理员权限的实例，B自我关闭，返回一个ExitCode给A，A收到通知也关闭，一切不就解决了嘛。这就是我的方案。
当然也可以不启动C，B关闭Ａ，Ｂ继续以管理员权限运行，但是如何返回状态给Ａ让A自我结束，或者B干掉A，就不是一个ExitCode可以解决的了，通讯或查找程序可能变得复杂。
下面附上创建、查询、删除计划任务的VB.NET代码：
Public Class Form1
Private Const TASK_TRIGGER_LOGON = &H9
Private Const TASK_ACTION_EXEC = &H0
Private Const TASK_CREATE = &H2
Private Const TASK_CREATE_OR_UPDATE = &H6
Private Const TASK_RUNLEVEL_HIGHEST = &H1
Private Const TASK_LOGON_GROUP = &H4
Private Const TASK_LOGON_NONE = &H0 Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load End Sub Public Function CreateOrUpdateTask(ByVal strTaskName As String, ByVal strAuthor As String, ByVal strTaskDescription As String, ByVal strPath As String, ByVal strWorkingDir As String, Optional ByVal strArguments As String = "", Optional ByVal bUseHighestSecLevel As Boolean = True) As Long
Dim objService As Object
objService = CreateObject("Schedule.Service")
objService.Connect() Dim objTaskFolder As Object
objTaskFolder = objService.GetFolder("\") Dim objTaskDef As Object
objTaskDef = objService.NewTask() Dim objPrincipal As Object
objPrincipal = objTaskDef.principal
With objPrincipal
.LogonType =
.RunLevel = TASK_RUNLEVEL_HIGHEST
End With Dim colTriggers As Object
Dim objTrigger As Object
Dim colActions As Object
Dim objAction As Object
Dim objInfo As Object
Dim objSettings As Object
colTriggers = objTaskDef.Triggers
objTrigger = colTriggers.Create(TASK_TRIGGER_LOGON)
objTrigger.Enabled = True
colActions = objTaskDef.Actions
objAction = colActions.Create(TASK_ACTION_EXEC)
objAction.Path = strPath
objAction.WorkingDirectory = strWorkingDir
objAction.Arguments = strArguments
objInfo = objTaskDef.RegistrationInfo
objInfo.Author = strAuthor
objInfo.Description = strTaskDescription
objSettings = objTaskDef.Settings
With objSettings
.Enabled = True
.Hidden = False
.StartWhenAvailable = True
.DisallowStartIfOnBatteries = False
.StopIfGoingOnBatteries = False
.AllowHardTerminate = False
End With Try
If bUseHighestSecLevel Then
objTaskFolder.RegisterTaskDefinition(strTaskName, objTaskDef, TASK_CREATE_OR_UPDATE, "Administrators", , TASK_LOGON_GROUP)
Else
objTaskFolder.RegisterTaskDefinition(strTaskName, objTaskDef, TASK_CREATE_OR_UPDATE, , , TASK_LOGON_NONE)
End If
Catch ex As Exception
Return Err.Number
End Try CreateOrUpdateTask =
objService = Nothing
objInfo = Nothing
objTaskFolder = Nothing
objTaskDef = Nothing
objPrincipal = Nothing
End Function Public Function DeleteTask(ByVal strTaskName As String) As Long
Dim objService As Object
Dim objTaskFolder As Object Try
objService = CreateObject("Schedule.Service")
objService.Connect()
objTaskFolder = objService.GetFolder("\")
objTaskFolder.DeleteTask(strTaskName, )
Catch ex As Exception
Return Err.Number
End Try objService = Nothing
objTaskFolder = Nothing
DeleteTask =
End Function Public Function TaskAvailable(taskName) As Boolean
Dim service = CreateObject("Schedule.Service")
Call service.Connect() ' Get the task folder that contains the tasks.
Dim rootFolder
rootFolder = service.GetFolder("\") Dim taskCollection
taskCollection = rootFolder.GetTasks() Dim numberOfTasks
numberOfTasks = taskCollection.Count If numberOfTasks = Then
Debug.Print("No tasks are registered.")
Else
Debug.Print("Number of tasks registered: " & numberOfTasks) Dim registeredTask
For Each registeredTask In taskCollection
Dim name As String = registeredTask.Name
Debug.Print("Task Name: " & name)
Dim taskState
Select Case registeredTask.State
Case ""
taskState = "Unknown"
Case ""
taskState = "Disabled"
If (name = taskName) Then
TaskAvailable = False
Exit Function
End If
Case ""
taskState = "Queued"
Case ""
taskState = "Ready"
Case ""
taskState = "Running"
Case Else
taskState = "Unknown"
End Select
If (name = taskName) Then
TaskAvailable = True
Exit Function
End If
Debug.Print(" Task State: " & taskState)
Next
End If
TaskAvailable = False
End Function Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
MsgBox(CreateOrUpdateTask("Test", Interaction.Environ("USERDOMAIN") & "\" & Interaction.Environ("USERNAME"), "a Test Task", Application.ExecutablePath, Application.StartupPath, "", True))
End Sub Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
MsgBox(DeleteTask("Test"))
End Sub
End Class