How to enable visual styles without a manifest

Question

According to the docs:

"If you want your application to use ComCtl32.dll version 6, you must add an application manifest or compiler directive to specify that version 6 should be used if it is available."

Notice the logical OR above? So what is this mysterious compiler directive?

I've got a native Win32 C++ application that is wholly contained in a single .cpp file. There are no resource files, manifest files, etc. I'd like to keep it that way, but I would also like to use visual styles.

Answer 1

There's actually a third way with no manifests whatsoever, though it's rather hacky:

#include <windows.h>

// NOTE: It is recommended that you delay-load ComCtl32.dll (/DelayLoad:ComCtl32.dll)
// and that you ensure this code runs before GUI components are loaded.
// Otherwise, you may get weird issues, like black backgrounds in icons in image lists.
ULONG_PTR EnableVisualStyles(VOID)
{
    TCHAR dir[MAX_PATH];
    ULONG_PTR ulpActivationCookie = FALSE;
    ACTCTX actCtx =
    {
        sizeof(actCtx),
        ACTCTX_FLAG_RESOURCE_NAME_VALID
            | ACTCTX_FLAG_SET_PROCESS_DEFAULT
            | ACTCTX_FLAG_ASSEMBLY_DIRECTORY_VALID,
        TEXT("shell32.dll"), 0, 0, dir, (LPCTSTR)124
    };
    UINT cch = GetSystemDirectory(dir, sizeof(dir) / sizeof(*dir));
    if (cch >= sizeof(dir) / sizeof(*dir)) { return FALSE; /*shouldn't happen*/ }
    dir[cch] = TEXT('\0');
    ActivateActCtx(CreateActCtx(&actCtx), &ulpActivationCookie);
    return ulpActivationCookie;
}