How to trap keypress event in MSword using VSTO? - vb.net

Question

I am new to VSTO VB.Net programming. and I am developing a word application level Addin and want to trap keypress event. I have tried various codes of hooking but none is working. I want to use application level hook using WH_KEYBOARD instead of WH_KEYBOARD_LL. The following code which I have tried traps just one key stroke after that it stops. Moreover I could not understand where to put trap the keystrokes. How would I use the following for handling key events.
Public Event KeyDown As KeyEventHandler
Public Event KeyPress As KeyPressEventHandler
Public Event KeyUp As KeyEventHandler
The code that I am using is
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, ByVal wParam 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, ByVal wParam 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, New KeyEventArgs(DirectCast(Asc(Chr(lParam.vkCode)), Keys) Or modifiers))
ElseIf Not CapsLock AndAlso shifting Then
RaiseEvent KeyUp(Me, New KeyEventArgs(DirectCast(Asc(Chr(lParam.vkCode)), Keys) Or modifiers))
ElseIf Not shifting Then
If CapsLock Then
RaiseEvent KeyUp(Me, New KeyEventArgs(DirectCast(Asc(Chr(lParam.vkCode)), Keys) Or modifiers))
Else
RaiseEvent KeyUp(Me, New KeyEventArgs(DirectCast(Asc(Chr(lParam.vkCode)), 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

Answer 1

Your question is a possible duplicate of:
How to get the "KeyPress" event from a Word 2010 Addin (developed in C#)?
How to raise an event on MS word Keypress
Capturing keydown event of MS Word using C#
... however, the answer remains the same: you simply can't :)
In my answer to the last of the questions listed above I explain the reason behind this in a bit more detail, and also covers a possible alternative solution involving the WindowSelectionChange event.