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File download in C++ metro style application

    Question

  • I am trying to write an application which can download a file from a server I am using a file save picker along with the c++ BackgroundDownloader

    since there may be different files from the server I want to append the file extension dynamically by splitting the specified URI .Below is the code I am using for this.

      Uri^ source = ref new Uri(StringTrimmer::Trim(serverAddressField->Text));
    	  String^ filenameExt= serverAddressField->Text;
    
    	  const wchar_t* pntr=filenameExt->Data();
    	
    	  int l= filenameExt->Length();
    
    	  auto temp =std::map<wchar_t,String^>();
    	  auto test= temp.find(filenameExt->Data()[l-3]);
    
    
    	   String^ destination1 = StringTrimmer::Trim(fileNameField->Text);
    	  FileSavePicker^ savePicker = ref new FileSavePicker();
            savePicker->SuggestedStartLocation = PickerLocationId::DocumentsLibrary;
    		
            auto plainTextExtensions = ref new Platform::Collections::Vector<String^>();
            plainTextExtensions->Append(".pdf");
    		plainTextExtensions->Append(".txt");
    		 savePicker->FileTypeChoices->Insert("Portable Document file", plainTextExtensions);
            savePicker->FileTypeChoices->Insert("Plain text", plainTextExtensions);
            savePicker->SuggestedFileName = "New Document";
    
            create_task(savePicker->PickSaveFileAsync()).then([this](StorageFile^ file)
            {
    		Uri^ source = ref new Uri("http://www.microsoft.com/about/mspreview/windows8/Windows8_RP_Product_guide.pdf");
    			 BackgroundDownloader^ downloader = ref new BackgroundDownloader();
    			 DownloadOperation^ download = downloader->CreateDownload(source, file);
          /*  BackgroundDownloader^ downloader = ref new BackgroundDownloader();
            DownloadOperation^ download = downloader->CreateDownload(source, destinationFile);*/
    
    			 Output->Text="Downloading " + source->AbsoluteUri + " to " + file->Name + ", " + download->Guid;
    
            // Attach progress and completion handlers.
            HandleDownloadAsync(download, true);

    I tried to split the string using the following code but its not working properly. 

      const wchar_t* pntr=filenameExt->Data();

      int l= filenameExt->Length();

      auto temp =std::map<wchar_t,String^>();
      auto test= temp.find(filenameExt->Data()[l-3]);

    Don't mind for the silly question. As this is the first time I am working with c++ .

    Tuesday, August 28, 2012 11:10 AM

Answers