Using _SendMessage to send keys to Notepad

[oasis375 4]

[Sorry I meant "send keystrokes"]

Title is self explaining. I don't understand why this doesn't work:

#include <SendMessage.au3>
#include <WindowsConstants.au3>

Run("notepad.exe")
$hWnd = WinWait("[CLASS:Notepad]", "", 10)
$hControl = ControlGetHandle($hWnd, "", "Edit1")

;This works
ControlSend($hControl, "", "", "hello")
;This doesn't work
_SendMessage($hControl, "hello")

[Just in case. This is a "thought experiment"; don't ask me why I don't use Send(), ControlSend(), etc.]

Edited May 5, 2015 by oasis375

[Chimp 451]

_SendMessage doesn't send "strings", it sends "events" to controls
have a look here 

[Danp2 305]

Because you are using _SendMessage in an inappropriate way.

Hint: The second parameter should be a numeric value, not a string.

[oasis375 4]

Thank you, guys. This is what works:

#include <SendMessage.au3>
#include <WindowsConstants.au3>

Run("notepad.exe")
$hWnd = WinWait("[CLASS:Notepad]", "", 10)
$hControl = ControlGetHandle($hWnd, "", "Edit1")
$text = "this is a line"
$struct_string = DllStructCreate("char[" & StringLen($text) + 1 & "]")
DllStructSetData($struct_string, 1, $text)
_SendMessageA($hControl, $WM_SETTEXT, 0, DllStructGetPtr($struct_string))

 

[Chimp 451]

how did you go from that trivial mistake in the first post to this fine example posted here so quickly?
Good! great progress in so little time...