利用WindowsAPI獲得系統高級功能
VB無疑是最先進的編程工具之一，但在涉及windows 32位系統的核心編程方面——譬如一些高級功能的實現上，它仍然顯得有些力不從心，這需要我們充分利用vb的強大的Windows API函數調用能力來彌補。以下代碼將向您展示如何利用Windows API控制系統托盤（圖標）區、開始菜單、任務欄以及禁用/起用ctrl-alt-del、退出網絡登錄、立即關機、重新啟動等系統高級功能。
啟動VB6，建立一個標準exe工程，添加14個command按鈕，caption屬性依次為 “隱藏開始菜單”、“顯示開始菜單”、“隱藏系統托盤”、“顯示系統托盤”、“禁用 ctrl-alt-del”、“起用 ctrl-alt-del”、“隱藏任務欄”、“顯示任務欄”、“立即重新啟動”、“關機”、“退出網絡登陸”、“顯示關機對話框”，調整上述控件到適當位置，雙擊窗體，寫入以下代碼：
Option Explicit Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long '尋找窗口列表中第一個符合指定條件的頂級窗口 'lpClassName指向包含了窗口類名的空中止（C語言）字串的指針；或設為零，'表示接收任何類 'lpWindowName指向包含了窗口文本（或標簽）的空中止（C語言）字串的指針；'或設為零，表示接收任何窗口標題 |
Private Declare Function ShowWindow Lib "user32" (ByVal hwnd As Long, ByVal nCmdShow As Long) As Long '控制窗口的可見性 'hwnd窗口句柄，要向這個窗口應用由nCmdShow指定的命令 'nCmdShow為窗口指定可視性方面的一個命令 |
| Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As String) As Long '在窗口列表中尋找與指定條件相符的第一個子窗口 'hWnd1在其中查找子的父窗口 'hWnd2從這個窗口后開始查找。這樣便可利用對FindWindowEx的多次調用找到符合條件的所有子窗口。如設為零，表示從第一個子窗口開始搜索 |
Private Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Long, ByVal dwReserved As Long) '退出windows，并用特定的選項重新啟動 |
Private Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, ByVal uParam As Long, ByRef lpvParam As Any, ByVal fuWinIni As Long) As Long '允許獲取和設置數量眾多的windows系統參數 'uAction指定要設置的參數 |
Private Const EWX_LOGOFF = 0'中止進程，然后注銷 Private Const EWX_SHUTDOWN = 1'關掉系統電源 Private Const EWX_REBOOT = 2'重新引導系統 Private Const EWX_FORCE = 4'強迫中止沒有響應的進程 Private Const SPI_SCREENSAVERRUNNING = 97 |
| Private Sub Command1_Click() '隱藏開始菜單 Dim Handle As Long, FindClass As Long FindClass = FindWindow("Shell_TrayWnd", "") Handle = FindWindowEx(FindClass, 0, "Button", vbNullString) ShowWindow Handle, 0 End Sub |
Private Sub Command11_Click() '起用 ctrl-alt-del Dim ret As Integer Dim pOld As Boolean ret = SystemParametersInfo(SPI_SCREENSAVERRUNNING, True, pOld, 0) End Sub |
Private Sub Command12_Click() '禁用 ctrl-alt-del Dim ret As Integer Dim pOld As Boolean ret = SystemParametersInfo(SPI_SCREENSAVERRUNNING, False, pOld, 0) End Sub |
Private Sub Command13_Click() '立即重新啟動 ExitWindowsEx EWX_REBOOT, 0 End Sub |
| Private Sub Command14_Click() '關機 ExitWindowsEx EWX_SHUTDOWN, 0 End Sub |
| Private Sub Command15_Click() '退出網絡登陸 ExitWindowsEx EWX_LOGOFF, 0 End Sub |
| Private Sub Command16_Click() '顯示關機對話框 ExitWindowsEx EWX_FORCE, 0 End Sub |
| Private Sub Command2_Click() '顯示開始菜單 Dim Handle As Long, FindClass As Long FindClass = FindWindow("Shell_TrayWnd", "") Handle = FindWindowEx(FindClass, 0, "Button", vbNullString) ShowWindow Handle, 1 End Sub |
| Private Sub Command5_Click() '隱藏系統托盤 Dim FindClass As Long, Handle As Long FindClass = FindWindow("Shell_TrayWnd", "") Handle = FindWindowEx(FindClass, 0, "TrayNotifyWnd", vbNullString) ShowWindow Handle, 0 End Sub |
| Private Sub Command6_Click() '顯示系統托盤 Dim FindClass As Long, Handle As Long FindClass = FindWindow("Shell_TrayWnd", "") Handle = FindWindowEx(FindClass, 0, "TrayNotifyWnd", vbNullString) ShowWindow Handle, 1 End Sub |
| Private Sub Command7_Click() '顯示任務欄 Dim FindClass As Long, FindClass2 As Long, Parent As Long, Handle As Long FindClass = FindWindow("Shell_TrayWnd", "") FindClass2 = FindWindowEx(FindClass, 0, "ReBarWindow32", vbNullString) Parent = FindWindowEx(FindClass2, 0, "MSTaskSwWClass", vbNullString) Handle = FindWindowEx(Parent, 0, "SysTabControl32", vbNullString) ShowWindow Handle, 0 End Sub |
| Private Sub Command8_Click() '隱藏任務欄 Dim FindClass As Long, FindClass2 As Long, Parent As Long, Handle As Long FindClass = FindWindow("Shell_TrayWnd", "") FindClass2 = FindWindowEx(FindClass, 0, "ReBarWindow32", vbNullString) Parent = FindWindowEx(FindClass2, 0, "MSTaskSwWClass", vbNullString) Handle = FindWindowEx(Parent, 0, "SysTabControl32", vbNullString) ShowWindow Handle, 1 End Sub |
| Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer) End End Sub |
本文中的部分api函數及其相應的常數較少用到，希望編程愛好者能夠有所借鑒和斧正，如果有問題歡迎與我聯系[email protected]。