Accessing controls within Property Sheet

Question

I'm creating a Windows application using a PropertySheet (Wizard97 type), but I'm unclear how to access the controls from within the dialog callback.

First I setup the property sheet.

psp[1].dwSize = sizeof(PROPSHEETPAGE);
psp[1].dwFlags = PSP_HIDEHEADER ;
psp[1].hInstance = g_hInst;
psp[1].pszTemplate = MAKEINTRESOURCE(IDD_SETUP);
psp[1].pszIcon = NULL;
psp[1].pfnDlgProc = (DLGPROC)ButtonsDlgProc;
psp[1].lParam = 0;

So within the ButtonsDlgProc, I can't access the controls I've added to the dialog.

LRESULT CALLBACK ButtonsDlgProc(HWND hdlg,
      UINT uMessage,
      WPARAM wParam,
      LPARAM lParam)
{
CButton * button;

switch (uMessage)
{
    case WM_COMMAND:
    switch (wParam)
    {
        case IDC_CHECK1:
            button = (CButton *)GetDlgItem(hdlg, IDC_CHECK1);
            button1IsChecked = button->GetCheck();
            break;

GetDlgItem returns a handle, but when invoking button->GetCheck(), I get an exception. Is this the proper way to access control members?

Answer 1

The simplest way to achieve it would be

button = (CButton *)CWnd::FromHandle(::GetDlgItem(hdlg, IDC_CHECK1));