Closing childwindow close also mainwindow

[rommi]

Hi all!

I have created a Mainwindow with a lot of childwindows in it. The quantity of ChildNow is dynamic cause i want to close or add Childwindwos during the Runtime. Every Childwindow has no titelbar but it has a little button to close the childwindow. Now my problem is that if i close one of the existing Childwindws then the Mainwindow is also closing. How can i avoid it? Here a quick description how my code works:

HWND *Childwin = new HWND(100); // dynamic array for the children
HWND mainhwnd; // mainwindow

Winmain (...)
{
...

// create mainwindow
mainhwnd = ....

// create some childs
for(i=0;i<10;i++)
{
Childwin[i] = ....
}

...

}


Callback(...)
{
...
WM_COMMAND
...
default
if a certain quit-Childbutton is pressed
DestroyWindow(Child[i]);

WM_DESTROY
PostQuitMessage(0);

WM_PAINT
BitBlt...
draw Child and Main...

WM_TIMER
...
...
}

I guess always if i want to close a childwindow a WM_COMMAND message is generated but also a WM_DESTROY message what also close the mainwindow, but how can i avoid this or anybody has a better concept to close childwindows inside mainwindow?

My second question is that i want add childwindows during the runtime. On a certain event on my desktop a new childwindow should created and appear in the mainwindow as the other childrens. Does anybody has a starting clue how i can realize?

Many thanks in advance, best regards rommi

[VictorN]

Set break points in the "callback", debug your App and see what happens when you "close" child window

[rommi]

Hi VictorN,
thx for your replay. Here is my reduced code to describe the problem. If i close the childwindow the main window is also closeing:

#include <windows.h>
#include <stdio.h>
#include <fstream>
#include <time.h>
#include <stdlib.h>
#include <cstdlib>
#include <sstream>
using namespace std;
#pragma comment(lib, "user32.lib")

// ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
// XXXXXX Deklaration XXXXXXXX
// XXXXXX ------------- XXXXXXXX
// ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
LRESULT CALLBACK WndProc( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam );
LPCSTR MainClassName = "TESTTEST";
HINSTANCE hInstance;
#define CHILDX 123
HWND hWnd; // Mainwindow
HWND Child; // Childwindows

// ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
// XXXXXX CHILD - SUB XXXXXXXX
// ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
void FerstellChilder()
{
Child = CreateWindowEx (WS_EX_COMPOSITED,MainClassName,"Child", WS_CHILD |
WS_OVERLAPPEDWINDOW |WS_VISIBLE ,0,0,500,53,hWnd, (HMENU) CHILDX,hInstance, NULL);
}

// ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
// XXXXXX ------------- XXXXXXXX
// XXXXXX MAIN XXXXXXXX
// ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
//==================================================================//
// Create Main-Window //
//==================================================================//

WNDCLASSEX wc;
MSG wmsg;

wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(GetModuleHandle(NULL), IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = CreateSolidBrush(RGB(0, 128, 0));
wc.lpszMenuName = MainClassName;
wc.lpszClassName = MainClassName;
wc.hIconSm = LoadIcon(GetModuleHandle(NULL), IDI_APPLICATION);

if(!RegisterClassEx(&wc)){return 0;}
hWnd = CreateWindowEx(WS_EX_COMPOSITED, MainClassName, "TEST", WS_OVERLAPPEDWINDOW |
WS_VISIBLE,CW_USEDEFAULT, CW_USEDEFAULT, 698, 130, NULL, NULL, hInstance, NULL);

//==================================================================//
// Create Childwindow over function //
//==================================================================//
FerstellChilder();
//==================================================================//
// send messages //
//==================================================================//
while(GetMessage(&wmsg, NULL, 0, 0))
{
TranslateMessage(&wmsg);
DispatchMessage(&wmsg);
}
return wmsg.wParam;
}

// ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
// XXXXXX ------------- XXXXXXXX
// XXXXXX Callback XXXXXXXX
// ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ

LRESULT CALLBACK WndProc( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam )
{
PAINTSTRUCT ps;
switch( uMsg )
{
//________________________________________________
case WM_COMMAND :
{
switch( LOWORD( wParam ) )
{
case CHILDX:
DestroyWindow(Child); //close Child
break;
}
break;
}
break;
//________________________________________________
case WM_DESTROY :
{
PostQuitMessage(0);
return 0;
}
//________________________________________________
case WM_PAINT :
{
BeginPaint(hWnd, &ps); //paint mainwindow
EndPaint(hWnd, &ps);

BeginPaint(Child, &ps); //paint childwindow
EndPaint(Child, &ps);
return 0;
}
//________________________________________________
default :{return( DefWindowProc( hWnd, uMsg, wParam, lParam ));}
}
return( 0L );
}


I create a breakpoint on the begin of the callback function and a braekpoint of the DestroyWindow function. On the breakpoint on the begin of the callback i get this local messages:

hWnd 0x000d07ba {unused=??? } HWND__ *
unused CXX0030: Fehler: Ausdruck kann nicht ausgewertet werden
uMsg 36 unsigned int
wParam 0 unsigned int
lParam 1243124 long

Im a newbie and at the moment i cant realy interpret what the this message means "unused CXX30: Error:.....". On the breakpoint of the DestroyWindow function i get not messages or warnings. May be this helps to describe what i mean. regards, rommi

[VictorN]

Well, your problem is you are using the same window class for the main and for the child window. It means that the same window procedure is used for these both.
But in this procedure you call PostQuitMessage in the case of WM_DESTROY! So handling this message for the child window your procedure causes the thread to exit!

To fix the problem use another window class/another procedure (which won't call PostQuitMessage) for the child window.

[rommi]

Hi VictorN,
this is the solution! thanks a lot!
best regards, rommi