VB.NET实现关机和重新启动

Private Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Integer, ByVal dwReserved As Integer) As Integer

Const EWX_FORCE As Short = 4

Const EWX_LOGOFF As Short = 0

Const EWX_REBOOT As Short = 2

Const EWX_SHUTDOWN As Short = 1

Dim retval As Integer

' 定义Esc按键

Const VK_ESCAPE As Short = &H1Bs

Private Sub Command1_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles Command1.Click

If Option1.Checked Then

' 注销当前用户

retval = ExitWindowsEx(EWX_FORCE, 0)

ElseIf Option2.Checked Then

' 关闭计算机

retval = ExitWindowsEx(EWX_SHUTDOWN, 0)

ElseIf Option3.Checked Then

' 重新启动

retval = ExitWindowsEx(EWX_REBOOT, 0)

End If

End Sub

Private Sub Command2_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles Command2.Click

Me.Close()

End Sub

' 按Esc键时，结束应用程序

Private Sub Form1_KeyPress(ByVal eventSender As System.Object, ByVal eventArgs As System.Windows.Forms.KeyPressEventArgs) Handles MyBase.KeyPress

Dim KeyAscii As Short = Asc(eventArgs.KeyChar)

If KeyAscii = VK_ESCAPE Then

Me.Close()

End If

If KeyAscii = 0 Then

eventArgs.Handled = True

End If

End Sub

本实例通过使用ExitWindowEx()API函数来达到关机和重新启动的目的。在ExitWindowEx()函数中，参数uFlags指定要进行何种操作。在表86-2中列出了参数uFlags的值及其说明。

表86-2参数uFlags的值及说明

常量名	值	说明
EWX_FORCE	4	终止所有进程,包括没有响应的进程,并注销Windows
EWX_REBOOT	2	重新启动系统
EWX_SHUTDOWN	1	关闭系统
EWX_LOGOFF	0	终止所有正在运行的进程,并注销Windows