vb.net休眠 vbnet sleep
求计算机休眠代码
VB.NET中实现"关机/休眠/重启/注销"的类Imports System
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Imports System.Text
Imports System.Diagnostics
Imports System.Runtime.InteropServices
Public Class WindowsController
Public Enum RestartOptions
LogOff = 0
PowerOff = 8
Reboot = 2
ShutDown = 1
Suspend = -1
Hibernate = -2
End Enum
Public Structure LUID
Dim LowPart As Integer
Dim HighPart As Integer
End Structure
Public Structure LUID_AND_ATTRIBUTES
Dim pLuid As LUID
Dim Attributes As Integer
End Structure
Public Structure TOKEN_PRIVILEGES
Dim PrivilegeCount As Integer
Dim Privileges As LUID_AND_ATTRIBUTES
End Structure
Private Const TOKEN_ADJUST_PRIVILEGES = H20
Private Const TOKEN_QUERY = H8
Private Const SE_PRIVILEGE_ENABLED = H2
Private Const FORMAT_MESSAGE_FROM_SYSTEM = H1000
Private Const EWX_FORCE = 4
Declare Function LoadLibrary Lib "kernel32" Alias "LoadLibraryA" (ByVal lpLibFileName As String) As IntPtr
Declare Function FreeLibrary Lib "kernel32" (ByVal hLibModule As IntPtr) As Integer
Declare Function GetProcAddress Lib "kernel32" (ByVal hModule As IntPtr, ByVal lpProcName As String) As IntPtr
Declare Function SetSuspendState Lib "Powrprof" (ByVal Hibernate As Integer, ByVal ForceCritical As Integer, ByVal DisableWakeEvent As Integer) As Integer
Declare Function OpenProcessToken Lib "advapi32.dll" (ByVal ProcessHandle As IntPtr, ByVal DesiredAccess As Integer, ByRef TokenHandle As IntPtr) As Integer
Declare Function LookupPrivilegeValue Lib "advapi32.dll" Alias "LookupPrivilegeValueA" (ByVal lpSystemName As String, ByVal lpName As String, ByRef lpLuid As LUID) As Integer
Declare Function AdjustTokenPrivileges Lib "advapi32.dll" (ByVal TokenHandle As IntPtr, ByVal DisableAllPrivileges As Integer, ByRef NewState As TOKEN_PRIVILEGES, ByVal BufferLength As Integer, ByRef PreviousState As TOKEN_PRIVILEGES, ByRef ReturnLength As Integer) As Integer
Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Integer, ByVal dwReserved As Integer) As Integer
Declare Function FormatMessage Lib "kernel32" Alias "FormatMessageA" (ByVal dwFlags As Integer, ByVal lpSource As IntPtr, ByVal dwMessageId As Integer, ByVal dwLanguageId As Integer, ByVal lpBuffer As StringBuilder, ByVal nSize As Integer, ByVal Arguments As Integer) As Integer
Public Sub ExitWindows(ByVal how As RestartOptions, ByVal force As Boolean)
Select Case how
Case RestartOptions.Suspend
SuspendSystem(False, force)
Case RestartOptions.Hibernate
SuspendSystem(True, force)
Case Else
ExitWindows(Convert.ToInt32(how), force)
End Select
End Sub
Protected Sub ExitWindows(ByVal how As Integer, ByVal force As Boolean)
EnableToken("SeShutdownPrivilege")
If force Then how = how Or EWX_FORCE
If (ExitWindowsEx(how, 0) = 0) Then Throw New PrivilegeException(FormatError(Marshal.GetLastWin32Error()))
End Sub
Protected Sub EnableToken(ByVal privilege As String)
If Not CheckEntryPoint("advapi32.dll", "AdjustTokenPrivileges") Then Return
Dim tokenHandle As IntPtr = IntPtr.Zero
Dim privilegeLUID = New LUID()
Dim newPrivileges = New TOKEN_PRIVILEGES()
Dim tokenPrivileges As TOKEN_PRIVILEGES
If (OpenProcessToken(Process.GetCurrentProcess().Handle, TOKEN_ADJUST_PRIVILEGES Or TOKEN_QUERY, tokenHandle)) = 0 Then Throw New PrivilegeException(FormatError(Marshal.GetLastWin32Error()))
If (LookupPrivilegeValue("", privilege, privilegeLUID)) = 0 Then Throw New PrivilegeException(FormatError(Marshal.GetLastWin32Error()))
tokenPrivileges.PrivilegeCount = 1
tokenPrivileges.Privileges.Attributes = SE_PRIVILEGE_ENABLED
tokenPrivileges.Privileges.pLuid = privilegeLUID
Dim Size As Integer = 4
If (AdjustTokenPrivileges(tokenHandle, 0, tokenPrivileges, 4 + (12 * tokenPrivileges.PrivilegeCount), newPrivileges, Size)) = 0 Then Throw New PrivilegeException(FormatError(Marshal.GetLastWin32Error()))
End Sub
Protected Sub SuspendSystem(ByVal hibernate As Boolean, ByVal force As Boolean)
If Not CheckEntryPoint("powrprof.dll", "SetSuspendState") Then Throw New PlatformNotSupportedException("The SetSuspendState method is not supported on this system!")
SetSuspendState(Convert.ToInt32(IIf(hibernate, 1, 0)), Convert.ToInt32(IIf(force, 1, 0)), 0)
End Sub
Protected Function CheckEntryPoint(ByVal library As String, ByVal method As String) As Boolean
Dim libPtr As IntPtr = LoadLibrary(library)
If Not libPtr.Equals(IntPtr.Zero) Then
If Not GetProcAddress(libPtr, method).Equals(IntPtr.Zero) Then
FreeLibrary(libPtr)
Return True
End If
FreeLibrary(libPtr)
End If
Return False
End Function
Protected Function FormatError(ByVal number As Integer) As String
Dim Buffer = New StringBuilder(255)
FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, IntPtr.Zero, number, 0, Buffer, Buffer.Capacity, 0)
Return Buffer.ToString()
End Function
End Class
Public Class PrivilegeException
Inherits Exception
Public Sub New()
MyBase.New()
End Sub
Public Sub New(ByVal message As String)
MyBase.New(message)
End Sub
End Class
例如实现注销功能:
Dim shutdown As New WindowsController()
shutdown.ExitWindows(shutdown.RestartOptions.LogOff, False
求助:VB.NET中线程的休眠时间最长是多少
设定Timer象间触发事件再给handler发消息处理行处理完重置timer间进入循环即随便用wait类土办容易系统判定进程挂死kill
VB中Timer和Doevents的问题!
LZ是想做延迟的功能吧
其实 你可以参考下 Windows核心编程的消息驱动 相关知识
DoEvents 是程序响应Windows消息 如Click,MouseMove以及键盘事件等
因为循环时,系统会给该线程分配大量的CPU时间(空间),因此死循环不能够及时
响应Windows消息,比如用户在循环时拖动了窗体,如果没有DoEvents就会出现
没有响应之类的现象
Sleep 是线程休眠函数,你这个程序所在的线程会在指定时间内"与世隔绝"
Sleep 1 就是1毫秒 对CPU来说也许做了很多事,但是对人就不算是个时间
Timer样能延迟又不咱CPU 你可以尝试一下多线程,但是还要考虑线程同步的问题
其实也可以换一种方式来做,也就是说同样的功能可以有不同的实现方式
参考下这里,也许对你有帮助:
能发现DoEvents这些问题说明你尝试了,而且初步研究了
不明白的地方再问我,希望能帮上忙.
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