2
私は、Silverlightを使用してwp7で音楽プレーヤーを開発しています。私のエンドユーザーは、ローミング中にインターネットに接続できません。私は彼らに電話で音楽をダウンロードするオプションを与えたい。 これは、Wi-Fi接続があるときに音楽をダウンロードするために使用できるダウンロードマネージャーを書いています。 私は私が直面しているのは、私の音楽は私のサーバーに保存されており、私はWebCLientクラスを使って電話で音楽をダウンロードしています。 ファイルのサイズが68 MBを超えた場合、私のアプリケーションはOutOfMemory例外を受け取ります。 ここでコードである：WebClientを使用してWP7で大きなファイルを読み込んで保存する
公共ボイドDownloadKirtan（KirtanViewModel kirtanVm、BOOL QueueItem = TRUE）{
{
if (kirtanVm.LocationPath != null)
{
WebClient webClient = new WebClient();
//webClient.AllowWriteStreamBuffering = false;
// webClient.AllowReadStreamBuffering = false;
if (QueueItem == false)
{
//App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload[kirtanVm] = webClient;
// App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload.Add(kirtanVm//
webClient = App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload[kirtanVm];
kirtanVm.IsDownloadedForOfflineViewing = "Started";
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
webClient.OpenReadAsync(kirtanVm.LocationPath, kirtanVm);
}
else if (!App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload.ContainsKey(kirtanVm))
{
App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload.Add(kirtanVm, webClient);
kirtanVm.IsDownloadedForOfflineViewing = "Started";
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
webClient.OpenReadAsync(kirtanVm.LocationPath, kirtanVm);
}
// webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(webClient_DownloadProgressChanged);
}
}
}
空隙webClient_OpenReadCompleted（オブジェクト送信者、OpenReadCompletedEventArgs E） {
KirtanViewModel kirtanVm = e.UserState as KirtanViewModel;
try
{
if (e.Cancelled == false)
{
if (e.Result != null)
{
((WebClient)sender).OpenReadCompleted -= webClient_OpenReadCompleted;
#region Isolated Storage Copy Code
IsolatedStorageFile isolatedStorageFile = IsolatedStorageFile.GetUserStoreForApplication();
bool checkQuotaIncrease = IncreaseIsolatedStorageSpace(e.Result.Length);
if (checkQuotaIncrease)
{
string VideoFile = "";
VideoFile = GetUrlOfOfflineContent(kirtanVm);
using (IsolatedStorageFileStream isolatedStorageFileStream = new IsolatedStorageFileStream(VideoFile, FileMode.Create, isolatedStorageFile))
{
long VideoFileLength = (long)e.Result.Length;
byte[] byteImage = new byte[VideoFileLength];
e.Result.Read(byteImage, 0, byteImage.Length);
isolatedStorageFileStream.Write(byteImage, 0, byteImage.Length);
kirtanVm.IsDownloadedForOfflineViewing = "True";
kirtanVm.DownloadSize = "Size=" + (VideoFileLength/1000000).ToString() + " MB";
kirtanVm.DownloadProgress = "100%";
Settings.OfflineKirtanContents.Value.Add(kirtanVm);
AddRemoveKirtanInOfflineModels(kirtanVm, true);
}
#endregion
}
else
{
kirtanVm.IsDownloadedForOfflineViewing = "False";
App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload.Remove(kirtanVm);
MessageBox.Show("There is not enough space in your phone to store this media. You need " + e.Result.Length + " bytes of storage.Please free some offline contents you have downloaded by going to Offline content managemnt screen in Settings Section and try again or increase the storage on your phone.");
}
// mediaFile.SetSource(isolatedStorageFileStream);
// mediaFile.Play();
// progressMedia.Visibility = Visibility.Collapsed;
}
}
}
catch (Exception ex)
{
kirtanVm.IsDownloadedForOfflineViewing = "Failed";
//App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload.Remove(kirtanVm);
MessageBox.Show(ex.ToString());
}
}
私が問題を抱えているのは、ストリームオブジェクトであるe.resultを取得したときです。 isolatedStoreFileStreamに書き込むには、それをバイト配列にもう一度読み込んで、それをisolatedstoragefileに保存する必要があります。これは非効率的で、2倍のメモリを消費します。 WebClient e.resultストリームオブジェクトによって60MBのメモリ（60MBファイル用）、配列に変換するために60MB。したがって、メモリ消費量は128 MBです。大きなファイルをダウンロードしてIsolatedStorageに保存するより良い方法はありますか？
更新：メモリ内のすべてを読み込むのではなく、チャンクサイズを使って以下のコードを使用しています。 MB
あなたはそれを一チューを記述する必要が無効webClient_OpenReadCompleted（オブジェクト送信者、OpenReadCompletedEventArgs E） {
KirtanViewModel kirtanVm = e.UserState as KirtanViewModel;
try
{
if (e.Cancelled == false)
{
if (e.Result != null)
{
((WebClient)sender).OpenReadCompleted -= webClient_OpenReadCompleted;
#region Isolated Storage Copy Code
bool checkQuotaIncrease = IncreaseIsolatedStorageSpace(e.Result.Length);
if (checkQuotaIncrease)
{
string VideoFile = "";
VideoFile = GetUrlOfOfflineContent(kirtanVm);
ThreadPool.QueueUserWorkItem(k =>{
using (IsolatedStorageFile isolatedStorageFile = IsolatedStorageFile.GetUserStoreForApplication())
{
using (IsolatedStorageFileStream isolatedStorageFileStream = new IsolatedStorageFileStream(VideoFile, FileMode.Create, isolatedStorageFile))
{
long VideoFileLength = (long)e.Result.Length;
using (BinaryWriter writer = new BinaryWriter(isolatedStorageFileStream))
{
Stream resourceStream = e.Result;//streamResourceInfo.Stream;
long length = resourceStream.Length;
byte[] buffer = new byte[32];
int readCount = 0;
using (BinaryReader reader = new BinaryReader(resourceStream))
{ // read file in chunks in order to reduce memory consumption and increase performance
while (readCount < length)
{
int actual = reader.Read(buffer, 0, buffer.Length);
readCount += actual;
writer.Write(buffer, 0, actual);
}
}
}
kirtanVm.IsDownloadedForOfflineViewing = "True";
kirtanVm.DownloadSize = "Size=" + (VideoFileLength/1000000).ToString() + " MB";
kirtanVm.DownloadProgress = "100%";
Settings.OfflineKirtanContents.Value.Add(kirtanVm);
AddRemoveKirtanInOfflineModels(kirtanVm, true);
}
}
});
//byte[] byteImage = new byte[VideoFileLength];
//e.Result.Read(byteImage, 0, byteImage.Length);
// e.re
//ThreadPool.QueueUserWorkItem(k =>{
// isolatedStorageFileStream.Write(byteImage, 0, byteImage.Length);
//isolatedStorageFileStream.Close();
//Application.Current.RootVisual.Dispatcher.BeginInvoke(()=>
// {
// kirtanVm.IsDownloadedForOfflineViewing = "True";
// kirtanVm.DownloadSize = "Size=" + (VideoFileLength/1000000).ToString() + " MB";
// kirtanVm.DownloadProgress = "100%";
// Settings.OfflineKirtanContents.Value.Add(kirtanVm);
// AddRemoveKirtanInOfflineModels(kirtanVm, true);
// });
//});
//StreamWriter writer=new StreamWriter(isolatedStorageFileStream);
// writer.Write(e.Result);
// writer.Close();
// isolatedStorageFileStream.Write(
// e.Result.Write(
// isolatedStorageFileStream.Write(byteImage, 0, byteImage.Length);
// isolatedStorageFileStream.Close();
}
#endregion
else
{
kirtanVm.IsDownloadedForOfflineViewing = "False";
App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload.Remove(kirtanVm);
MessageBox.Show("There is not enough space in your phone to store this media. You need " + e.Result.Length + " bytes of storage.Please free some offline contents you have downloaded by going to Offline content managemnt screen in Settings Section and try again or increase the storage on your phone.");
}
}
}
else
{
lock (App.ViewModel.LockForCancelForCurrentOfflineDownload)
{
if (App.ViewModel.cancelInitiatedByUserForCurrentOfflineDownload)
{
kirtanVm.IsDownloadedForOfflineViewing = "False";
// kirtanVm.IsOfflineDownloadCancelled = false;
App.ViewModel.cancelInitiatedByUserForCurrentOfflineDownload = false;
}
else
{
if (kirtanVm.IsDownloadedForOfflineViewing == "Started")// don't queue things again
{
kirtanVm.IsDownloadedForOfflineViewing = "Failed";
// bool ItemExist = App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload.Any(k => k.Key.Kirtan.KirtanId == kirtanVm.Kirtan.KirtanId);
DownloadKirtan(kirtanVm, false);
}
}
}
}
}
catch (Exception ex)
{
kirtanVm.IsDownloadedForOfflineViewing = "Failed";
//App.ViewModel.ActiveInstancesOfWebClientForKirtanDownload.Remove(kirtanVm);
MessageBox.Show(ex.ToString());
}
}
おかげ Verinder
です。long length = resourceStream.Length;間違いです。それを含めません –