在VC中，CFILE的GetLength()函数可直接得到大小：
CFile cf;
 // Attempt to open thefile for reading.
 if( !cf.Open( pszFilename, CFile::modeRead ) )
  return( FALSE );
 // Get the size of the file and store
 // in a local variable. .
 DWORD dwSize;
 dwDibSize = cf.GetLength();

、
提示 error C2440: '=' : cannot convert from 'unsigned long (__thiscall CFile::*)(void) const' to 'unsigned long'
        Conversion is a valid standard conversion, which can be performed implicitly or by use of static_cast, C-style cast or function-style cast

为什么呢。。。

dwDibSize 写错了吧.
GetLength的返回值是 ULONGLONG,是unsigned __int64
所以要不改dwSize的类型为ULONGLONG,要不强转一下  dwSize = (ULONGLONG)cf.GetLength();