请参考： OPENFILENAME Structure lStructSize Specifies the length, in bytes, of the structure. Windows NT 4.0: In an application that is compiled with WINVER and _WIN32_WINNT >= 0x0500, use OPENFILENAME_SIZE_VERSION_400 for this member. Windows 2000/XP: Use sizeof (OPENFILENAME) for this parameter.
OPENFILENAME Structure
lStructSize
Specifies the length, in bytes, of the structure.
Windows NT 4.0: In an application that is compiled with WINVER and _WIN32_WINNT >= 0x0500, use OPENFILENAME_SIZE_VERSION_400 for this member. Windows 2000/XP: Use sizeof (OPENFILENAME) for this parameter.