Ejemplos usando el Api de windows para Visual basic

223 - Activar y desactivar las teclas NumLock, ScrollLock y CapsLock

Código fuente enviado por Julio R. Espinosa

El ejemplo permite mediante las funciones del api GetKeyboardState, SetKeyboardState, GetKeyState y keybd_event, activar y desactivar dichas teclas.

Nota: En versiones windows Nt , se usa la función keybd_event, y en anteriores la función SetKeyboardState. ( La versión de windows se recupera con la función GetVersionEx )

Ejemplo

Colocar en un formulario tres controles CheckBox en una matriz ( Check1(0), Check1(1) y Check1(2))

vista del formulario para activar las teclas

Código fuente en el formulario

Option Explicit ' Estructura para la función del api GetVersionEx Private Type OSVERSIONINFO dwOSVersionInfoSize As Long dwMajorVersion As Long dwMinorVersion As Long dwBuildNumber As Long dwPlatformId As Long szCSDVersion As String * 128 End Type ' Declaraciones Api Private Declare Function GetKeyboardState Lib "user32" (pbKeyState As Byte) As Long Private Declare Function SetKeyboardState Lib "user32" (lppbKeyState As Byte) As Long Private Declare Function GetKeyState Lib "user32" (ByVal nVirtKey As Long) As Long Private Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" ( _ lpVersionInformation As OSVERSIONINFO) As Long Private Declare Sub keybd_event Lib "user32" ( _ ByVal bVk As Byte, _ ByVal bScan As Byte, _ ByVal dwFlags As Long, _ ByVal dwExtraInfo As Long) ' Declaración de constantes Private Const KEYEVENTF_EXTENDEDKEY = &H1 Private Const KEYEVENTF_KEYUP = &H2 Private Const VER_PLATFORM_WIN32_NT = 2 Private Const VER_PLATFORM_WIN32_WINDOWS = 1 Private bNoClick As Boolean ' cambia el estado de las teclas ''''''''''''''''''''''''''''''''''''''''''''''''''''' Private Sub check1_Click(Index As Integer) Dim OINFO As OSVERSIONINFO Dim ret As Boolean Dim keys(0 To 255) As Byte If bNoClick Then Exit Sub OINFO.dwOSVersionInfoSize = Len(OINFO) GetVersionEx OINFO GetKeyboardState keys(0) Select Case Index ' Tecla NumLock ''''''''''''''''''''''''''''''' Case 0 ret = keys(vbKeyNumlock) ' Windows 95 / Windows 98 If OINFO.dwPlatformId = VER_PLATFORM_WIN32_WINDOWS Then keys(vbKeyNumlock) = Abs(Not ret) SetKeyboardState keys(0) 'Windows NT ElseIf OINFO.dwPlatformId = VER_PLATFORM_WIN32_NT Then keybd_event vbKeyNumlock, &H45, KEYEVENTF_EXTENDEDKEY Or 0, 0 keybd_event vbKeyNumlock, &H45, KEYEVENTF_EXTENDEDKEY Or KEYEVENTF_KEYUP, 0 End If ' Tecla CapsLock ''''''''''''''''''''''''''''''' Case 1 ret = keys(vbKeyCapital) ' Windows 95 / Windows 98 If OINFO.dwPlatformId = VER_PLATFORM_WIN32_WINDOWS Then keys(vbKeyCapital) = Abs(Not ret) SetKeyboardState keys(0) ' Windows NT ElseIf OINFO.dwPlatformId = VER_PLATFORM_WIN32_NT Then keybd_event vbKeyCapital, &H45, KEYEVENTF_EXTENDEDKEY Or 0, 0 keybd_event vbKeyCapital, &H45, KEYEVENTF_EXTENDEDKEY Or KEYEVENTF_KEYUP, 0 End If ' Tecla ScrollLock ''''''''''''''''''''''''''''''' Case 2 ret = keys(vbKeyScrollLock) ' Windows 95 / Windows 98 If OINFO.dwPlatformId = VER_PLATFORM_WIN32_WINDOWS Then keys(vbKeyScrollLock) = Abs(Not ret) SetKeyboardState keys(0) ' Windows NT ElseIf OINFO.dwPlatformId = VER_PLATFORM_WIN32_NT Then keybd_event vbKeyScrollLock, &H45, KEYEVENTF_EXTENDEDKEY Or 0, 0 keybd_event vbKeyScrollLock, &H45, KEYEVENTF_EXTENDEDKEY Or KEYEVENTF_KEYUP, 0 End If End Select End Sub Private Sub Form_Load() Dim NumLock As Long Dim CapsLock As Long Dim ScrollLock As Long ' devuelve el estado de las teclas NumLock = GetKeyState(vbKeyNumlock) CapsLock = GetKeyState(vbKeyCapital) ScrollLock = GetKeyState(vbKeyScrollLock) ' Establece los ckeckbox para mostrar el estado bNoClick = True If NumLock And 1 Then Check1(0).Value = 1 bNoClick = False bNoClick = True If CapsLock And 1 Then Check1(1).Value = 1 bNoClick = False bNoClick = True If ScrollLock And 1 Then Check1(2).Value = 1 bNoClick = False Check1(0).Caption = "NumLock" Check1(1).Caption = "CapsLock" Check1(2).Caption = "ScrollLock" End Sub

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