SendMessage to another dialog window

georgiek50

I'm having a problem sending a message from one window to another in my (Win32) application. A little background: 1) It's a dialog based app 2) It consists of a tab control and several child window dialogs I want to send the text of an edit control from one tab/child window to another tab/child window's list box using: SendMessage(hwnd, LB_ADDSTRING, 0, (LPARAM) szString); However I can not get them to communicate. I can't figure this out (never attempted it before). I have a single function handling all messages of each child window of the tab control. Everything works great as long as I'm updating the window/tab in view. Can anyone point me in the right direction? Thanks in advance.

Waldermort

You cannot do that with a string. The string is in the memory of your process, all that you are sending is the address, which the second process will not be able to read. To send a string send the WM_COPYDATA message instead. But this will not allow you to add it to a listbox like you are trying.

realJSOP

Make sure your message handler is prototyped as follows: in the header file:

afx_msg LRESULT OnHandleMyMessage(WPARAM wParam, LPARAM lParam);

and in the cpp file:

BEGIN_MESSAGE_MAP(CMyClass, CDialog)
ON_MESSAGE(LB_ADDSTRING, OnHandleMyMessage)
END_MESSAGE_MAP()

LRESULT CMyClass::OnHandleMyMessage(WPARAM wParam, LPARAM lParam)
{
// your code goes here

return 1L;

}

Also, you should call PostMessage unless you need to wait for the message handler to return.

"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
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"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

georgiek50

Thanks for the reply. I'm quite new at coding and can't quite decipher what you provided, but are you suggesting I subclass the control?

Waldermort

He means, make sure you have correctly configured the message handler. But this is only valid if you are using MFC.

georgiek50

I see. I'm using Win32. Is there a workaround for this?

prasad_som

He doesn't mention two windows from two processes here.

Prasad Notifier using ATL | Operator new[],delete[][^]

prasad_som

georgiek50 wrote:

SendMessage(hwnd, LB_ADDSTRING, 0, (LPARAM) szString);

What value does this function returns ? I assume hwnd is handle to target list box.

Prasad Notifier using ATL | Operator new[],delete[][^]

malaugh

Not familiar with Win32, If you can, add something like the following: BOOL MyDialog::PreTranslateMessage(MSG* pMsg) { // catch any WM_USER messages if (pMsg->message == WM_USER) { // see if it's your message if (pMsg->wParam == LB_ADDSTRING) { ... process the message .... .....