Sendmessage() $wParam and $lParam

[CountyIT]

I have been reading and am a tad confused. When using Sendmessage am I free to make $wParam and $lParam whetever I want?

Ideally I would like $wParam to be an Integer (my code for something) and $lParam to be a string. The one that is scaring me a little is $lParam being a string, of say 100 characters. Am I going to run in to problems with this?

[PhoenixXL]

Why not try and see if there is some problems

[CountyIT]

Because I might not have problems but that doesn't mean they don't exist. Hence the question

[FireFox]

http://msdn.microsoft.com/en-us/library/windows/desktop/ms644950(v=vs.85).aspx Edited April 8, 2013 by FireFox

[CountyIT]

Interesting link. I think I read that one at least twice before posting the question. I didn't find any specfics about the $wParam or the $lParam in that link.

[BrewManNH]

The parameters wParam and iParam are Windows message specific, they're determined by what the msg you're sending is. Are you using this with a "private" message to an application you're creating, or are you sending a Windows message to one? Also, what kind of problems are you asking about in your first post?

[MDCT]

what kind of problems are you asking about in your first post?

I think the op wants to know the character limit that can be sent with $lParam. And maybe what kind of problem it can cause if many characters are being sent.

[BrewManNH]

That's what I was thinking too, but the OP never specified what he/she was anticipating might happen.

[kylomas]

CountyIT,

I have been reading and am a tad confused. When using Sendmessage am I free to make $wParam and $lParam whetever I want

I think you might have a misconception about what _sendmessage is/does. What are you trying to do?

Specific to your questions:

1 - "When using Sendmessage am I free to make $wParam and $lParam whetever I want?"

Depends, answer BrewmanNH's questions

2 - " Ideally I would like $wParam to be an Integer (my code for something) and $lParam to be a string.

The one that is scaring me a little is $lParam being a string, of say 100 characters.

Am I going to run in to problems with this?"

This can be done with a user defined message. I believe the string limit i 65536 (don't remember exactly). However, I'm not

sure why you would want to pass data around like this.

kylomas

edit: holy crap, I suck with this editor

Edited April 9, 2013 by kylomas

[CountyIT]

I really simply wanted to pass a string like "Hello World" from one program I have written to another program I have written but it doesn't appear that this is the way to do it. Just playing I set $WParam to 10 and $lParam to "Hello World" and did a sendmessage() to the other program. The $wParam transfered correctly but the $lParam did not. It came in as a hex number not a string so I am assuming $lParam cannot be a string. It has to be a number?????

[kylomas]

No, you can pass a string, as I said in my previous post.

[kylomas]

CountyIT,

The following is an example of how to pass a string using a user defined message.

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

local $my_msg = $wm_user+1

local $gui010 = guicreate('',900,150)
local $aSize = wingetclientsize($gui010)
local $lbl010 = guictrlcreatelabel('',10,20,$aSize[0]-20,50,$ss_sunken)
guictrlsetfont(-1,12,600,default,'courier new')
local $btn010 = guictrlcreatebutton('Send Message',10,$aSize[1]-40,$aSize[0]-20,30,$ss_sunken)
guisetstate()

GUIRegisterMsg($my_msg,"_user01")

while 1
switch guigetmsg()
case $gui_event_close
Exit
case $btn010
_sendmessage($gui010,$my_msg,200,'This is a message sent by actioning my user defined message',0,'wparam','str')
EndSwitch
WEnd

func _user01($hWnd, $uMsg, $wParam, $lParam)

$mystr = dllstructcreate('char mystring[128]', $lparam)
guictrlsetdata($lbl010,' LPARAM = ' & dllstructgetdata($mystr,1) & @crlf & ' WPARAM = ' & int($wparam))

endfunc

thread has an example of actioning a control in another thread using a user defined message.

edit: I'm not sure that you can pass a string because I do not know how to get addressability to the structure used to store the lparam data. Perhaps one of the heavy hitters knows....

edit2: there are a bunch of threads on inter process communications

kylomas

Edited April 9, 2013 by kylomas