Pass values (longs) between two PB programs.

TerryHough · Post by **TerryHough** » Fri Sep 09, 2005 4:49 pm

I'm sure I have seen a post explaining how to do this, but I cannot find it
today.

Program A optionally launches Program B

I really need the Program B to be able to access the contents of a
gadget in Program A (the calling program), manipulate it, and then update
the original gadget's contents in the active Program A.

Anybody got a pointer for me?

Killswitch · Post by **Killswitch** » Fri Sep 09, 2005 4:53 pm

I think there's an example of inter-program comminication on Freak's website.

GedB · Post by **GedB** » Fri Sep 09, 2005 6:20 pm

Accessing another windows controls is very easy, since controls are publiclly exposed and accessible using SendMessage.

GadgetID() returns the handle needed to identify the gadget.

Compile the following example a A.exe and B.exe.

Code: Select all

;A.pb

If OpenWindow(0, 0, 0, 100, 50,  #PB_Window_WindowCentered|#PB_Window_SystemMenu, "Program A")
  If CreateGadgetList(WindowID(0))
    StringGadget(0, 0, 0, 100, 20, "") 
    ButtonGadget(1, 0, 30, 100, 20, "Launch B")
  EndIf
EndIf

Repeat
  e = WaitWindowEvent()
  Select e
    Case #PB_Event_Gadget
      Select EventGadgetID()
        Case 1
          RunProgram("B.exe", Str(GadgetID(0)), ".")
      EndSelect 
  EndSelect
Until e = #PB_Event_CloseWindow

Code: Select all

;B.pb

Declare.s GetTextFromA()

Awnd = Val(ProgramParameter())

If OpenWindow(0, 0, 0, 100, 50,  #PB_Window_WindowCentered|#PB_Window_SystemMenu, "Program B")
  If CreateGadgetList(WindowID(0))
    TextGadget(0, 0, 0, 100, 20, "") 
    ButtonGadget(1, 0, 30, 100, 20, "Get Text from A")
    
  EndIf
EndIf

GetTextFromA()

Repeat
  e = WaitWindowEvent()
  Select e
    Case #PB_Event_Gadget
      Select EventGadgetID()
        Case 1
          GetTextFromA()
      EndSelect 
  EndSelect
    
  
Until e = #PB_Event_CloseWindow

Procedure.s GetTextFromA()
          Shared Awnd
          buffer.s = Space(255)
          SendMessage_(Awnd, #WM_GETTEXT, 255, @buffer)
          SetGadgetText(0, PeekS(@buffer))
EndProcedure

Droopy · Post by **Droopy** » Fri Sep 09, 2005 7:08 pm

Very cool

TerryHough · Post by **TerryHough** » Fri Sep 09, 2005 9:42 pm

GedB wrote:Accessing another windows controls is very easy, since controls are publiclly exposed and accessible using SendMessage.

Thanks for your code. It works well. Unfortunately, I haven't been able
to get it to work with my programs. I will keep trying.

Terry

GedB · Post by **GedB** » Sat Sep 10, 2005 11:14 am

Terry,

Post some code, see if we can help.

Tranquil · Post by **Tranquil** » Sat Sep 10, 2005 5:00 pm

I use normaly the following methode:

I create an invisible window with an unique ID and waiting for messages in his callback.

Another application uses FindWindow_() to get the handle of the recipient window. Then I only use SendMessage_ API to send a user defined Message (#WM_User+x) plus an optional lparam and/ or wparam.

cheers

Mike

GreenGiant · Post by **GreenGiant** » Sat Sep 10, 2005 8:24 pm

I'd also reccomend using user-defined messages. But if you are going to use them, don't forget to use RegisterWindowMessage_() to avoid trouble.

lexvictory · Post by **lexvictory** » Sun Sep 11, 2005 1:34 pm

GreenGiant wrote:I'd also reccomend using user-defined messages. But if you are going to use them, don't forget to use RegisterWindowMessage_() to avoid trouble.

i think u only need to use that wen u use #hwnd_broadcast .....

if u know the exact hwnd then u can use #wm_user etc

GreenGiant · Post by **GreenGiant** » Sun Sep 11, 2005 3:43 pm

I'm not an expert, but I understood that RegisterWindowMessage should always be used.
Say for example that you are sending a pointer to a string between two programs using #WM_User+17 (directly, not broadcasting it). Suppose another program is broadcasting a pointer to a function and is also using WM_User+17. Then because you didn't use RegisterWindowMessage to get an unique message your program will sometimes be sent the function pointer which could lead to problems if you try to write a string to it.

lexvictory · Post by **lexvictory** » Mon Sep 12, 2005 10:17 am

well, anyone using a #wm_user value in a broadcast message is pretty silly

doing so can cause all sorts of problems - like in ure example greengiant, u can still use registerwindowmessage to send a message to a hwnd that u know is ures, but if u know the hwnd u can use #wm_user+wateva ....

btw greengiant im not an expert either!!

also is this really needed?

Code: Select all

SetGadgetText(0, PeekS(@buffer))

cant it be:

Code: Select all

SetGadgetText(0, buffer)

?

GedB · Post by **GedB** » Mon Sep 12, 2005 11:21 am

I think Terry should walk before he can run.

Once he has the hand of sending standard messages, he can start registering his own.

One the registering of messages the SDK has the following to say:

Only use RegisterWindowMessage when more than one application must process the same message. For sending private messages within a window class, an application can use any integer in the range WM_USER through 0x7FFF. (Messages in this range are private to a window class, not to an application. For example, predefined control classes such as BUTTON, EDIT, LISTBOX, and COMBOBOX may use values in this range.)

lexvictory · Post by **lexvictory** » Mon Sep 12, 2005 11:25 am

thats wat i meant.... (the wm_user bit)

lexvictory · Post by **lexvictory** » Mon Sep 12, 2005 11:28 am

also, ive found that in purebasic if u use a window callback u can use either sendmessage_() or postmessage_()
but if u dont use a callback it seems as tho u have to use postmessage_() .....
correct me if im wrong please

TerryHough · Post by **TerryHough** » Mon Sep 12, 2005 8:25 pm

GedB wrote:I think Terry should walk before he can run.

I think Terry needs to learn to type or needs glasses!

Thanks, GedB, for the pointer. Works like a charm for me now.

Terry