The GetMimeType method returns the MIME type of the downloaded object store item.
_bstr_t bstrMimeType = spIDownloadRsp->GetMimeType();
...
// Obtain the specific response information contained in the custom DownloadRsp component
IDownloadRspPtr spIDownloadRsp(spIAppIntRsp);
_ASSERTE(spIDownloadRsp != 0);
std::cout << "PathName=" << (LPCSTR) spIDownloadRsp->GetFilePathName() << std::endl;
std::cout << "MimeType=" << (LPCSTR) spIDownloadRsp->GetMimeType() << std::endl;
std::cout << "FileSize=" << spIDownloadRsp->GetContentSize() << " bytes" << std::endl;
...