Simulating keyboard

What do I best use to simulate keypresses to a window? Right now I'm using sendmessage and findwindowex to send keys to a certain class in a window, but the only thing I can get to work is WM_CHAR. If I want to simulate things like arrow presses, do I have to use keydown and keyup or syskey in succession? Thanks.

use keydown, keyup with the virtual keycode:

VB Code:

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" ( _
                ByVal hwnd As Long, _
                ByVal wMsg As Long, _
                ByVal wParam As Long, _
                lParam As Any) As Long
 
Private Const WM_KEYDOWN = &H100
Private Const WM_KEYUP = &H101
 
Private Const VK_LEFT = &H25
Private Const VK_UP = &H26
Private Const VK_RIGHT = &H27
Private Const VK_DOWN = &H28
 
Private Sub Command1_Click()
    ' Assuming lhWnd is the handle of the edit box or whatever
    SendMessage lhWnd, WM_KEYDOWN, VK_LEFT, 1&
    SendMessage lhWnd, WM_KEYUP, VK_LEFT, 1&
End Sub

There's also a keyb_event API, but you can only direct key presses to the app currently in focus

Also the SendInput API might be an other alternative. Never tried it much though...

Sometimes it is necessary to use Postmessage instead of Sendmessage, as well. Specifically with Vb.net. Don't ask me why.