[Flags]
enum CREDUI_FLAGS
{
   INCORRECT_PASSWORD = 0x1,
   DO_NOT_PERSIST = 0x2,
   REQUEST_ADMINISTRATOR = 0x4,
   EXCLUDE_CERTIFICATES = 0x8,
   REQUIRE_CERTIFICATE = 0x10,
   SHOW_SAVE_CHECK_BOX = 0x40,
   ALWAYS_SHOW_UI = 0x80,
   REQUIRE_SMARTCARD = 0x100,
   PASSWORD_ONLY_OK = 0x200,
   VALIDATE_USERNAME = 0x400,
   COMPLETE_USERNAME = 0x800,
   PERSIST = 0x1000,
   SERVER_CREDENTIAL = 0x4000,
   EXPECT_CONFIRMATION = 0x20000,
   GENERIC_CREDENTIALS = 0x40000,
   USERNAME_TARGET_CREDENTIALS = 0x80000,
   KEEP_USERNAME = 0x100000,
}

VB Definition:

<Flags> _
Enum CREDUI_FLAGS
   INCORRECT_PASSWORD = &H1
   DO_NOT_PERSIST = &H2
   REQUEST_ADMINISTRATOR = &H4
   EXCLUDE_CERTIFICATES = &H8
   REQUIRE_CERTIFICATE = &H10
   SHOW_SAVE_CHECK_BOX = &H40
   ALWAYS_SHOW_UI = &H80
   REQUIRE_SMARTCARD = &H100
   PASSWORD_ONLY_OK = &H200
   VALIDATE_USERNAME = &H400
   COMPLETE_USERNAME = &H800
   PERSIST = &H1000
   SERVER_CREDENTIAL = &H4000
   EXPECT_CONFIRMATION = &H20000
   GENERIC_CREDENTIALS = &H40000
   USERNAME_TARGET_CREDENTIALS = &H80000
   KEEP_USERNAME = &H100000
End Enum