vb.net2008拦截关机或注销消息

在SystemEvents类中 可以 用户试图注销或关闭系统时发生。 (当用户试图注销或关闭系统时发生。当用户试图注销或关闭系统时发生。) 这个 事件处理函数中 可以找到如下方法

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Private Shared WM_QUERYENDSESSION As Integer = H11

Private Shared systemShutdown As Boolean = False

Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)

If m.Msg = WM_QUERYENDSESSION Then

'MessageBox.Show("queryendsession: this is a logoff, shutdown, or reboot")

systemShutdown = True

End If

' If this is WM_QUERYENDSESSION, the closing event should be raised in the base WndProc.

MyBase.WndProc(m)

End Sub 'WndProc

Private Sub Form1_Closing(ByVal sender As System.Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing

If (systemShutdown) Then

' Reset the variable because the user might cancel the shutdown.

systemShutdown = False

If (System.Windows.Forms.DialogResult.Yes = _

MessageBox.Show("My application", "Do you want to save your work before logging off?", MessageBoxButtons.YesNo)) Then

e.Cancel = True

Else

e.Cancel = False

End If

End If

End Sub

vb.net中如何禁止从任务栏关闭window

绑定窗体的FormClosing事件，执行e.Cancel = True即可。

如果你不想在任务栏上显示窗体，把窗体的ShowOnTaskbar设为False。

VB.net 多线程，导致无法响应

用

t.Suspend() 这个是挂起线程。是一个异步方法。

t.Sleep 我看了是一个同步方法。要等这个方法运行完了才继续下一步。

这和from.show和 from.showdiaglog区别差不多！

至于疑问2我也没找到原因。

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

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

vb.net里面怎么没有sleep啊

它在System.Threading命名空间的Thread类中定义了

直接用 System.Threading.Thread.Sleep()方法

System.Threading.Thread.Sleep(time )‘time为整数，单位毫秒

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

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