如何让PDF文件到临时存储文件，从URL中的Windows Phone 8.1

Question

var uri = new System.Uri("ms-appx:///Assets/FixesViaMail_17Dec.pdf", UriKind.Absolute); 
StorageFile file = await Windows.Storage.StorageFile.GetFileFromApplicationUriAsync(uri); 

这段代码，因为使用我的系统文件路径，但每当我使用此代码

var uri = new System.Uri("http://www.visa.com/assets/upload/11458/Hotel/Voucher114581423144270.pdf", UriKind.Absolute); 
StorageFile file = await Windows.Storage.StorageFile.GetFileFromApplicationUriAsync(uri); 

进出口工作非常出色那么我得到的错误是..... 价值不在预期范围内。

请帮我

Answer 1

GetFileFromApplicationUriAsync仅用于从您的应用程序中加载文件。要从网上阅读文件，您需要下载它。您可以使用HttpClient（对于小文件）或BackgroundDownloader（对于大文件）类来执行此操作。

var uri = new Uri("http://www.visa.com/assets/upload/11458/Hotel/Voucher114581423144270.pdf"); 
var httpClient = new HttpClient(); 

// Always catch network exceptions for async methods 
try 
{ 
    var response = await httpClient.GetAsync(uri); 
    // save response out 
} 
catch 
{ 
    // Details in ex.Message and ex.HResult.  
} 

查看Connecting to an HTTP server using Windows.Web.Http.HttpClient (XAML)了解更多详情。

var uri = new Uri("http://www.visa.com/assets/upload/11458/Hotel/Voucher114581423144270.pdf"); 
BackgroundDownloader download = new BackgroundDownloader(); 
DownloadOperation download = downloader.CreateDownload(uri, destinationFile); 

有关更多详细信息，请参见Transferring data in the background。