public static extern int URLDownloadToCacheFile( [In] Interop.IUnknown pUnk, string szURL, string szFileName, Int32 dwBufLength, Int32 dwReserved, [In] Interop.IBindStatusCallback pbsc);
public static extern int RegisterBindStatusCallback(IBindCtx pbc, [In] Interop.IBindStatusCallback pbsc, [Out] out Interop.IBindStatusCallback ppbsc, int dwReserved);