How to paint title bar window only? - winapi

Question

As mention from microsft doc. WM_NCPAINT is use to paint non-client area. it means like title bar. https://learn.microsoft.com/en-us/windows/win32/gdi/wm-ncpaint. But i get unexpected result. it paint client area too. and the weird one. title bar is gone. when launch. after ALT+TAB. the title bar appears with windows 7 style in windows 10.
class CMainFrame::CFrameWnd
{
public:
CMainFrame()
{
Create(
NULL,
"Hello World!",
WS_OVERLAPPED | WS_MINIMIZEBOX | WS_SYSMENU,
CRect(CPoint(100, 100), CSize(640, 360));
}
protected:
afx_msg void OnNcPaint();
DECLARE_MESSAGE_MAP()
}
BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd)
ON_WM_NCPAINT()
END_MESSAGE_MAP()
void CMainFrame::OnNcPaint()
{
PAINTSTRUCT ps;
CBrush brush;
brush.CreateSolidBrush(RGB(0, 0, 255));
CDC *pDC = BeginPaint(&ps);
pDC->FillRect(&ps.rcPaint, &brush);
EndPaint(&ps);
}
class CApplication : public CWinApp {
BOOL InitInstance() {
CMainFrame* mainWnd = new CMainFrame();
m_pMainWnd = mainWnd;
mainWnd->ShowWindow(SW_NORMAL);
mainWnd->UpdateWindow();
return TRUE;
}
};

Answer 1

In InitInstance, you must call the base class CWinApp::InitInstance() in the first line.
Create your main frame window using
CreateEx(0, AfxRegisterWndClass(0), "Hello World!",
WS_VISIBLE | WS_OVERLAPPEDWINDOW, 100, 100, 640, 360, NULL, 0);
Add PreCreateWindow to control the edges and other properties
int CMainFrame::PreCreateWindow(CREATESTRUCT& cs)
{
auto res = CFrameWnd::PreCreateWindow(cs);
cs.dwExStyle &= ~WS_EX_CLIENTEDGE;
return res;
}
Use the appropriate paint classes, CPaintDC dc(this), CWindowDC, for overriding OnPaint or OnNcPaint (avoid overriding OnNcPaint), use CClientDC dc(this) for other client area paints. Avoid calling WinAPI functions directly, for example avoid calling BeginPaint. You can also use Visual Studio to create a sample dialog based application, it will be easier to get started with that.