Windows Phone 官方樣本學習：Background Transfer Service Sample（後台傳輸）

此樣本顯示了如何使用後台傳輸服務在後台下載檔案，即使當應用程式不再運行在前台。

通過BackgroundTransferRequest 實現上傳下載

// Create the new transfer request, passing in the URI of the file to // be transferred.BackgroundTransferRequest transferRequest = new BackgroundTransferRequest(transferUri);// Set the transfer method. GET and POST are supported.transferRequest.Method = "GET";

通過TransferPreferences設定，是否用Wifi下載，是否充電時下載

 // If the WiFi-only checkbox is not checked, then set the TransferPreferences            // to allow transfers over a cellular connection.            if (wifiOnlyCheckbox.IsChecked == false)            {                transferRequest.TransferPreferences = TransferPreferences.AllowCellular;            }            if (externalPowerOnlyCheckbox.IsChecked == false)            {                transferRequest.TransferPreferences = TransferPreferences.AllowBattery;            }            if (wifiOnlyCheckbox.IsChecked == false && externalPowerOnlyCheckbox.IsChecked == false)            {                transferRequest.TransferPreferences = TransferPreferences.AllowCellularAndBattery;            }

 

使用隔離儲存區 (Isolated Storage)保持檔案

//在隔離儲存區 (Isolated Storage)中，判斷是否檔案已存在， 存在則刪除using (IsolatedStorageFile isoStore = IsolatedStorageFile.GetUserStoreForApplication())                {                    string filename = downloadFile;                    if (isoStore.FileExists(filename))                    {                        isoStore.DeleteFile(filename);                    }                 }

類BackgroundTransferRequest 屬性：

TransferStatus 傳輸狀態

TotalBytesToReceive 檔案大小

BytesReceived 已收到的檔案大小

 

代碼下載：

http://code.msdn.microsoft.com/wpapps/Background-Transfer-ce07e86f