How to group radio box buttons using Win32 API - c++

Question

I am working on a program with grouped check box and get confused on how the messages convey through different handles.
IDE:VC++, Win32 API
First, I have a main window which has a handle, say hWnd.
And in the WndProc function under case WM_CREATE, we create the "group button" and the individual 2 check boxes
Note: the first button uses "BS_GROUPBOX" style, and it was created with the handle hGrpButton while its parent handler is hWnd. The second and third button is "BS_AUTORADIOBUTTON" style and it's parent handle is hGrpButton.
If the 2 buttons are not grouped(so their parent hanlder would be hWnd), it is easy to check the status of them. Just simply go to case WM_COMMAND AND use their ID to check with the IsDlgButtonChecked function. After the two check boxes are grouped (their parent handle are not longer hWnd but hGrpButtons), I don't think the case WM_COMMAND will find their IDs since it is looking for the IDs under hWnd.
In short, after 2 check boxes are grouped, I don't know what is the event to monitor them.
case WM_CREATE:
{
/*Group for Radio button for preview/single or batch operation */
hGrpButtons=CreateWindowEx(WS_EX_WINDOWEDGE,
L"BUTTON",
L"Select Process Mode:",
WS_VISIBLE | WS_CHILD|BS_GROUPBOX, // Styles
10,280,
350,100,
hWnd,
NULL,
hInst, NULL);
CreateWindowEx(WS_EX_WINDOWEDGE,
L"BUTTON",
L"Batch Process Mode",
WS_VISIBLE | WS_CHILD|BS_AUTORADIOBUTTON, // Styles
10,20,
300,20,
hGrpButtons,
(HMENU)IDC_CHK1,
hInst, NULL);
CreateWindowEx(WS_EX_WINDOWEDGE,
L"BUTTON",
L"Single Process Mode (Preview Mode)",
WS_VISIBLE | WS_CHILD|BS_AUTORADIOBUTTON, // Styles
10,45,
300,20,
hGrpButtons,
(HMENU)IDC_CHK2,
hInst, NULL);

Answer 1

After read Coder_Dan's comment and MSDN article "http://msdn.microsoft.com/en-us/library/bb775947(v=vs.85).aspx#related_topics" about the button types, I finally sort it out.
BS_GROUPBOX is just an "eye candy" and it did no contribute to the group of the radio box!! The critical parameter to control the grouping is the "WS_GROUP"
How to group the radio box: Put the WS_GROUP in the first radio button's style. It will group the current radio button until it see the second WS_GROUP as mentioned by Coder_Dan.
Modification on my previous code
a. use hWnd as parent for all 4 radio buttons
b. Put WS_GROUP in the first and third button style so that we group the 1,2 and 3,4 radio buttons
c. Now you can go to the WM_COMMAND, and listen to the messages from the 4 buttons according to their IDs under the main window's handle hWnd
case WM_CREATE:
{
/*Group for Radio button for preview/single or batch operation */
hGrpButtons=CreateWindowEx(WS_EX_WINDOWEDGE,
L"BUTTON",
L"Select Process Mode:",
WS_VISIBLE | WS_CHILD|BS_GROUPBOX,// <----BS_GROUPBOX does nothing on the grouping
10,280,
350,100,
hWnd,
(HMENU)IDC_GRPBUTTONS,
hInst, NULL);
CreateWindowEx(WS_EX_WINDOWEDGE,
L"BUTTON",
L"first radio button",
WS_VISIBLE | WS_CHILD|BS_AUTORADIOBUTTON|WS_GROUP, // <---- WS_GROUP group the following radio buttons 1st,2nd button
10,520,
300,20,
hWnd, //<----- Use main window handle
(HMENU)IDC_CHK1,
hInst, NULL);
CreateWindowEx(WS_EX_WINDOWEDGE,
L"BUTTON",
L"second radio button",
WS_VISIBLE | WS_CHILD|BS_AUTORADIOBUTTON, // Styles
10,545,
300,20,
hWnd,
(HMENU)IDC_CHK2,
hInst, NULL);
CreateWindowEx(WS_EX_WINDOWEDGE,
L"BUTTON",
L"third radio button",
WS_VISIBLE | WS_CHILD|BS_AUTOCHECKBOX|WS_GROUP, //<---Start second group for 3rd,4th button
10,570,
300,20,
hWnd,
(HMENU)IDC_CHK3,
hInst, NULL);
CreateWindowEx(WS_EX_WINDOWEDGE,
L"BUTTON",
L"forth radio button",
WS_VISIBLE | WS_CHILD|BS_AUTORADIOBUTTON, // Styles
500,545,
300,20,
hWnd,
(HMENU)IDC_CHK4,
hInst, NULL);