Public Event KeyDown As KeyEventHandler

Public Event KeyPress As KeyPressEventHandler

Public Event KeyUp As KeyEventHandler

我正在使用的代码是

Imports System.ComponentModel

Imports System.Windows.Forms

Imports System.Runtime.InteropServices

Public Class KeyBoardHook
    Inherits Component
    Dim PredictString As String

#Region "     keyboardHook"
    Private Declare Auto Function LoadLibrary Lib "kernel32" (ByVal lpFileName As String) As IntPtr
    Private Declare Function UnhookWindowsHookEx Lib "user32" (ByVal hhk As IntPtr) As Boolean
    Private Declare Function SetWindowsHookEx Lib "user32" Alias "SetWindowsHookExA" (ByVal idHook As Integer,_
    ByVal lpfn As KeyboardProc,ByVal hmod As IntPtr,ByVal dwThreadId As Integer) As IntPtr
    Private Delegate Function KeyboardProc(ByVal Code As Integer,ByVal wParam As Integer,ByRef lParam As KBDLLHOOKSTRUCT) As IntPtr
    Private Declare Function CallNextHookEx Lib "user32" (ByVal hHook As IntPtr,ByVal nCode As Integer,ByRef lParam As KBDLLHOOKSTRUCT) As IntPtr

    Private Structure KBDLLHOOKSTRUCT
        Public vkCode As Integer
        Public scanCode As Integer
        Public flags As Integer
        Public time As Integer
        Public dwExtraInfo As Integer
    End Structure

    'Keyboard Constants
    Private Const HC_ACTION As Integer = 0
    Private Const WM_KEYDOWN As Integer = &H100
    Private Const WM_KEYUP As Integer = &H101
    Private Const WM_SYSKEYDOWN As Integer = &H104
    Private Const WM_SYSKEYUP As Integer = &H105

    Private Const WH_KEYBOARD As Integer = 2
    Public hKeyboardHook As IntPtr

    Public Event KeyDown As KeyEventHandler
    Public Event KeyPress As KeyPressEventHandler
    Public Event KeyUp As KeyEventHandler

    Private Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Integer) As Integer
    Private Declare Function GetKeyState Lib "user32" (ByVal nVirtKey As Integer) As Integer

    Private Const VK_ALT As Integer = &H12
    Private Const VK_CONTROL As Integer = &H11
    Private Const VK_SHIFT As Integer = 16

    <MarshalAs(UnmanagedType.FunctionPtr)> Private callback As KeyboardProc

    Public Sub HookKeyboard()
        callback = New KeyboardProc(AddressOf KeyboardCallback)
        Dim hInstance As IntPtr = LoadLibrary("User32")
        hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD,callback,hInstance,0)
        CheckHooked()
    End Sub

    Private Function KeyboardCallback(ByVal Code As Integer,ByRef lParam As KBDLLHOOKSTRUCT) As IntPtr
        Dim xy As System.Drawing.Point = Cursor.Position()
        Try
            If (Code = HC_ACTION Or Code = 3) Then
                Dim CapsLock As Boolean = GetKeyState(Keys.CapsLock) = 1
                Dim shifting As Boolean = False
                Dim modifiers As Keys
                If GetAsyncKeyState(VK_CONTROL) <> 0 Then
                    modifiers = modifiers Or Keys.Control
                End If
                If GetAsyncKeyState(VK_SHIFT) <> 0 Then
                    modifiers = modifiers Or Keys.Shift
                    shifting = True
                End If
                If GetAsyncKeyState(VK_ALT) <> 0 Then
                    modifiers = modifiers Or Keys.Alt
                End If
                Static lastKeys As Keys
                Select Case wParam
                    Case WM_KEYDOWN,WM_SYSKEYDOWN
                        RaiseEvent KeyDown(Me,New KeyEventArgs(DirectCast(Asc(Chr(lParam.vkCode)),Keys) Or modifiers))
                        If lastKeys <> (DirectCast(Asc(Chr(lParam.vkCode)),Keys) Or modifiers) Then
                            lastKeys = (DirectCast(Asc(Chr(lParam.vkCode)),Keys) Or modifiers)
                            If CapsLock AndAlso shifting Then
                                RaiseEvent KeyPress(Me,New KeyPressEventArgs(Char.ToLower(Chr(lParam.vkCode))))
                            ElseIf Not CapsLock AndAlso shifting Then
                                RaiseEvent KeyPress(Me,New KeyPressEventArgs(Char.ToUpper(Chr(lParam.vkCode))))
                            ElseIf Not shifting Then
                                If CapsLock Then
                                    RaiseEvent KeyPress(Me,New KeyPressEventArgs(Char.ToUpper(Chr(lParam.vkCode))))
                                Else
                                    RaiseEvent KeyPress(Me,New KeyPressEventArgs(Char.ToLower(Chr(lParam.vkCode))))
                                End If
                            End If
                        End If
                    Case WM_KEYUP,WM_SYSKEYUP
                        If CapsLock AndAlso shifting Then
                            RaiseEvent KeyUp(Me,Keys) Or modifiers))
                        ElseIf Not CapsLock AndAlso shifting Then
                            RaiseEvent KeyUp(Me,Keys) Or modifiers))
                        ElseIf Not shifting Then
                            If CapsLock Then
                                RaiseEvent KeyUp(Me,Keys) Or modifiers))
                            Else
                                RaiseEvent KeyUp(Me,Keys) Or modifiers))
                            End If
                        End If
                        lastKeys = Nothing
                End Select
            End If

            MsgBox("Keypressed is -> " & lParam.vkCode)
            Return CallNextHookEx(hKeyboardHook,Code,wParam,lParam)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Function

    Private Function keyboardHooked() As Boolean
        Return hKeyboardHook <> IntPtr.Zero
    End Function

    Public Sub UnhookKeyboard()
        If keyboardHooked() Then
            UnhookWindowsHookEx(hKeyboardHook)
        End If
    End Sub
#End Region
    Private Sub CheckHooked()
        If keyboardHooked() Then
            MsgBox("Keyboard hooked")
        Else
            MsgBox("Keyboard hook Failed: " & Err.LastDllError)
        End If
    End Sub
End Class