Button scaling in winapi - user-interface

Question

I am creating a simple calculator and I have a problem with scaling all elements. They have to scale with main window but I have no idea how to perform such a thing
Here is part of code:
#define ID_BUTTON0 0
#define ID_BUTTON1 1
#define ID_BUTTON2 2
#define ID_BUTTON3 3
#define ID_BUTTON4 4
...
case WM_CREATE:
{
CreateWindow(L"STATIC", L"", WS_VISIBLE | WS_CHILD,0, 0, 0, 0,hWnd, HMENU(ID_TEXTFIELD), 0, NULL);
CreateWindow(L"BUTTON", L"CE",WS_VISIBLE | WS_CHILD,0, 0, 0, 0,hWnd, HMENU(ID_BUTTONCE), 0, NULL);
CreateWindow(L"BUTTON", L"C",WS_VISIBLE | WS_CHILD,0, 0, 0, 0,hWnd, HMENU(ID_BUTTONC), 0, NULL);
CreateWindow(L"BUTTON", L"/",WS_VISIBLE | WS_CHILD,0, 0, 0, 0,hWnd, HMENU(ID_BUTTONDIV), 0, NULL);
CreateWindow(L"BUTTON", L"X",WS_VISIBLE | WS_CHILD,0, 0, 0, 0,hWnd, HMENU(ID_BUTTONMUL), 0, NULL);
CreateWindow(L"BUTTON", L"7",WS_VISIBLE | WS_CHILD,0, 0, 0, 0,hWnd, HMENU(ID_BUTTON7), 0, NULL);
CreateWindow(L"BUTTON", L"8",WS_VISIBLE | WS_CHILD,0, 0, 0, 0,hWnd, HMENU(ID_BUTTON8), 0, NULL);
CreateWindow(L"BUTTON", L"9",WS_VISIBLE | WS_CHILD,0, 0, 0, 0,hWnd, HMENU(ID_BUTTON9), 0, NULL);
...
resize_window(hWnd);
}
break;
case WM_SIZE:
{
resize_window(hWnd);
UpdateWindow(hWnd);
return 0;
}
void resize_window(HWND hWnd) {
int buttonxsize = WINDOWSIZEW / 4;
int buttonysize = WINDOWSIZEH / 6;
int posx = WINDOWSIZEW / 4;
int posy = WINDOWSIZEH / 6;
RECT rc;
GetClientRect(hWnd, &rc);
SetWindowPos(GetDlgItem(hWnd, ID_TEXTFIELD), 0, 0, 0, WINDOWSIZEW, buttonysize, SWP_NOZORDER);
SetWindowPos(GetDlgItem(hWnd, ID_BUTTONC), 0, 0, posy, buttonxsize, buttonysize, SWP_NOZORDER);
SetWindowPos(GetDlgItem(hWnd, ID_BUTTONCE), 0, posx, posy, buttonxsize, buttonysize, SWP_NOZORDER);
SetWindowPos(GetDlgItem(hWnd, ID_BUTTONDIV), 0, 2 * posx, posy, buttonxsize, buttonysize, SWP_NOZORDER);
SetWindowPos(GetDlgItem(hWnd, ID_BUTTONMUL), 0, 3 * posx, posy, buttonxsize, buttonysize, SWP_NOZORDER);
...
}
and so on...
After compiling I obtain such a thing :
How do I make it work?

Answer 1

HWND hwndTextField = CreateWindow(L"Static", L"",
WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON | WS_TABSTOP,
0, 0, WINDOWSIZEW, WINDOWSIZEH / 6,
hWnd, NULL, GetModuleHandle(NULL), NULL);
hwndTextField is declared on stack, it will be forgotten as soon as it goes out of scope, you won't be able find the control later (not easily anyway). hwndTextField should be declared as static or global. Better yet, assign an ID for each control using HMENU. This ID can be used to find the control. Also, when you click the button it sends WM_COMMAND message with that ID.
The style for this control should be WS_VISIBLE | WS_CHILD | WS_TABSTOP. However WS_TABSTOP is ignored unless this is created in a dialog.
And resize the controls in a separate function, so that it can be done from both WM_CREATE and WM_SIZE
For example
#define ID_TEXT 100
...
case WM_CREATE:
{
CreateWindow(L"STATIC", L"", WS_VISIBLE | WS_CHILD,
0, 0, 0, 0, hWnd, HMENU(ID_TEXT), 0, NULL);
...
resize_window(hWnd);
}
case WM_SIZE:
{
resize_window(hWnd);
return 0;
}
void resize_window(HWND hwnd)
{
RECT rc;
GetClientRect(hwnd, &rc);
//update ****
WINDOWSIZEW = rc.right;
WINDOWSIZEH = rc.bottom;
...
SetWindowPos(GetDlgItem(hWnd, ID_TEXT), 0, x, y, w, h, SWP_NOZORDER);
...
}