public bool DownloadMp3File (DownloadedMp3 mp3) {
WebClient client = new WebClient ();
string filePath = "";
bool wasDownload = false;
try {
string song = mp3.SongName;
filePath = @"mp3\" + song + ".mp3";
if (File.Exists (filePath)) {
File.Delete (filePath);
}
DateTime tryCountNow = DateTime.Now;
client = new WebClient ();
client.DownloadFileAsync (new Uri (mp3.Url), filePath);
client.DownloadProgressChanged += client_DownloadProgressChanged;
client.DownloadFileCompleted += client_DownloadFileCompleted;
DateTime start = DateTime.Now;
bool notDownload = false;
downloadComplete = false;
while (!downloadComplete) {
DateTime now = DateTime.Now;
TimeSpan ts = now - start;
int min = ts.Minutes;
int sec = ts.Seconds;
if (10 < sec && 0 == downloadProgress) {
notDownload = true;
client.CancelAsync ();
break;
}
if (min == 1) {
notDownload = true;
client.CancelAsync ();
break;
}
Thread.Sleep (30);
}
if (!notDownload) {
client.CancelAsync ();
client.OpenRead (mp3.Url);
int downloadedFileSize = Convert.ToInt32 (client.ResponseHeaders["Content-Length"]);
FileInfo localFile = new FileInfo (filePath);
if (localFile.Length == downloadedFileSize) {
wasDownload = true;
}
}
}
catch {
downloadProgress = 0;
downloadComplete = false;
}
finally {
client.CancelAsync ();
client.Dispose ();
downloadComplete = false;
downloadProgress = 0;
GC.Collect ();
if (!wasDownload) {
if (File.Exists (filePath)) {
FileSecurity fs = File.GetAccessControl (filePath);
File.Delete (filePath);
}
}
Application.Current.Dispatcher.BeginInvoke (
DispatcherPriority.Background,
new Action (() =>
MainWindow.label3.Content = ""
));
}
return wasDownload;
}
请帮忙!我有时会遇到这样的异常:
File.Delete 进程无法访问该文件,因为该文件正在被另一个进程使用
我找不到原因(我处置了WebClient)。
您的代码表明您在新下载的文件上遇到了“正在使用的文件”异常。许多防病毒程序会自动扫描新创建和/或新下载的文件,并且可能会延迟关闭文件句柄,直到扫描完成。
如果这是您的问题,那么您无能为力按时关闭文件。您可以切换到在扫描期间不会锁定文件的其他防病毒软件,也可以在尝试使用最近关闭的文件时实施延迟+重试循环。
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