//C++
typedef BOOL (WINAPI* SETAUTOROTATION)(BOOL bEnable);

SETAUTOROTATION SetAutoRotation = (SETAUTOROTATION)GetProcAddress(GetModuleHandle(TEXT("user32.dll")),(LPCSTR)2507);
if(SetAutoRotation != NULL)
{
  SetAutoRotation(TRUE);
}

要么

//C#
[DllImport("user32.dll",EntryPoint = "#2507")]
extern static bool SetAutoRotation(bool bEnable);

SetAutoRotation(true);