Keyboard Hook VB.Net

'''
''' Who To Use
'''
Module Module1
    Dim WithEvents kbHook As New KeyboardHook

    ' Some Useful Events
    Private Sub kbHook_KeyDown(ByVal xKey As System.Windows.Forms.Keys) Handles kbHook.KeyDown
        Console.WriteLine(xKey.ToString & " => KeyDown")
    End Sub

    Private Sub kbHook_KeyUp(ByVal xKey As System.Windows.Forms.Keys) Handles kbHook.KeyUp
        Console.WriteLine(xKey.ToString & " => KeyUp")
    End Sub

    Sub Main()

        ' Change User Input
        kbHook.ChangableChrs.Add(Keys.A, "1"c)
        kbHook.ChangableChrs.Add(Keys.B, "2"c)

        ' Start Hook
        kbHook.Start()
        Dim msg As MSG
        Dim ret As Integer
        ret = GetMessage(msg, IntPtr.Zero, 0, 0)
        While ret <> 0
        End While
    End Sub

End Module
''' ---------------------------------------

'''
''' KeyboardHook
'''
Imports System.Runtime.InteropServices

Public Class KeyboardHook

    Public ChangableChrs As New Dictionary(Of Keys, Char)

    Structure MSG
        Dim hwnd As Long
        Dim message As Long
        Dim wParam As Long
        Dim lParam As Long
        Dim time As Long
        Dim pt As Point
    End Structure

    <DllImport("user32.dll")>
    Public Shared Function DispatchMessage(ByRef lpmsg As MSG) As IntPtr
    End Function

    <DllImport("user32.dll")>
    Public Shared Function GetMessage(
     ByRef lpMsg As MSG,
     ByVal hWnd As IntPtr,
     ByVal wMsgFilterMin As UInteger,
     ByVal wMsgFilterMax As UInteger) As <MarshalAs(UnmanagedType.Bool)> Boolean
    End Function
    <DllImport("user32.dll")>
    Public Shared Function TranslateMessage(ByRef lpMsg As MSG) As <MarshalAs(UnmanagedType.Bool)> Boolean
    End Function

    <DllImport("kernel32.dll", CharSet:=CharSet.Auto)> _
    Public Shared Function GetModuleHandle(ByVal lpModuleName As String) As IntPtr
    End Function

    <DllImport("kernel32.dll")> _
    Public Shared Function GetCurrentThreadId() As UInteger
    End Function

    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>
    Private Overloads Shared Function SetWindowsHookEx(ByVal idHook As Integer, ByVal HookProc As KBDLLHookProc, ByVal hInstance As IntPtr, ByVal wParam As Integer) As Integer
    End Function
    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>
    Private Overloads Shared Function CallNextHookEx(ByVal idHook As Integer, ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer
    End Function
    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>
    Private Overloads Shared Function UnhookWindowsHookEx(ByVal idHook As Integer) As Boolean
    End Function

    <StructLayout(LayoutKind.Sequential)>
    Private Structure KBDLLHOOKSTRUCT
        Public vkCode As UInt32
        Public scanCode As UInt32
        Public flags As KBDLLHOOKSTRUCTFlags
        Public time As UInt32
        Public dwExtraInfo As UIntPtr
    End Structure

    <Flags()>
    Private Enum KBDLLHOOKSTRUCTFlags As UInt32
        LLKHF_EXTENDED = &H1
        LLKHF_INJECTED = &H10
        LLKHF_ALTDOWN = &H20
        LLKHF_UP = &H80
    End Enum


    Public Shared Event KeyDown(ByVal Key As Keys)
    Public Shared Event KeyUp(ByVal Key As Keys)

    Private Const WH_KEYBOARD_LL As Integer = 13
    Private Const HC_ACTION As Integer = 0
    Private Const WM_KEYDOWN = &H100
    Private Const WM_KEYUP = &H101
    Private Const WM_SYSKEYDOWN = &H104
    Private Const WM_SYSKEYUP = &H105

    Private Delegate Function KBDLLHookProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer

    Private KBDLLHookProcDelegate As KBDLLHookProc = New KBDLLHookProc(AddressOf KeyboardProc)
    Private HHookID As IntPtr = IntPtr.Zero

    Private Function KeyboardProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer
        If (nCode = HC_ACTION) Then
            Dim struct As KBDLLHOOKSTRUCT
            Select Case wParam
                Case WM_KEYDOWN, WM_SYSKEYDOWN
                    struct = CType(Marshal.PtrToStructure(lParam, struct.GetType()), KBDLLHOOKSTRUCT)

                    Dim xKey As Keys = struct.vkCode
                    RaiseEvent KeyDown(xKey)

                    If ChangableChrs.ContainsKey(xKey) Then
                        SendKeys.SendWait(ChangableChrs.Item(xKey))
                        Return 1
                    End If

                Case WM_KEYUP, WM_SYSKEYUP
                    Dim xKey As Keys = CType(Marshal.PtrToStructure(lParam, struct.GetType()), KBDLLHOOKSTRUCT).vkCode
                    RaiseEvent KeyUp(xKey)
            End Select
        End If

        Return CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam)
    End Function

    Public Sub Start()
        HHookID = SetWindowsHookEx(WH_KEYBOARD_LL, KBDLLHookProcDelegate, GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), 0)
        If HHookID = IntPtr.Zero Then
            Throw New Exception("Could not set keyboard hook")
        End If
    End Sub

    Protected Overrides Sub Finalize()
        If Not HHookID = IntPtr.Zero Then
            UnhookWindowsHookEx(HHookID)
        End If
        MyBase.Finalize()
    End Sub

End Class