/// <summary> 执行下载 </summary> bool DownloadPackages(DoWorkEventArgs e) { Directory.CreateDirectory(Context.UpdatePackagePath); Trace.TraceInformation("开始下载网络更新包"); var workerCount = Math.Max(1, Context.MultipleDownloadCount); var workers = new List <WebClient>(workerCount); var evt = new AutoResetEvent(false); var hasError = false; //Ping if (!string.IsNullOrEmpty(Context.UpdateMeta.UpdatePingUrl)) { try { Context.CreateWebClient().UploadData(new Uri(Context.UpdateMeta.UpdatePingUrl), new byte[0]); } catch (Exception) { } } //生成下载队列 Trace.TraceInformation("正在初始化 {0} 个WebClient", workerCount); for (var i = 0; i < workerCount; i++) { var client = Context.CreateWebClient(); client.DownloadFileCompleted += (s, e) => { var pkg = e.UserState as Package; var cnt = s as WebClient; pkg.LastError = e.Error; if (e.Error != null) { Trace.TraceWarning($"包【{pkg.Name}】下载失败:{e.Error.Message}"); OnPackageDownloadFailed(new PackageEventArgs(pkg)); } else if (pkg.IsLocalFileValid != true) { Trace.TraceWarning($"包【{pkg.Name}】MD5校验失败", "错误"); pkg.LastError = new Exception("不文件哈希值不正确或文件不存在"); OnPackageHashMismatch(new PackageEventArgs(pkg)); } if (pkg.LastError != null) { //如果出错,且重试次数在限制范围内,则重试 pkg.IncreaseFailureCounter(); if (pkg.RetryCount <= Context.MaxiumRetryDownloadCount) { Trace.TraceWarning($"包【{pkg.Name}】未能成功下载,正在进行第 {pkg.RetryCount} 次重试,最大重试次数为 {Context.MaxiumRetryDownloadCount}", "错误"); cnt.DownloadFileAsync(new Uri(pkg.SourceUri), pkg.LocalSavePath, pkg); OnPackageDownloadRetried(new PackageEventArgs(pkg)); return; } //标记出错 hasError = true; } //包下载完成事件 pkg.IsDownloading = false; pkg.IsDownloaded = pkg.LastError == null; OnPackageDownloadFinished(new PackageEventArgs(e.UserState as Package)); lock (Packages) { Trace.TraceInformation($"包【{pkg.Name}】下载操作完成:{(pkg.IsDownloaded ? "下载成功" : "下载失败")}"); evt.Set(); } }; client.DownloadProgressChanged += (s, e) => { var pkg = e.UserState as Package; pkg.DownloadedSize = e.BytesReceived; pkg.Size = e.TotalBytesToReceive > 0 ? e.TotalBytesToReceive : pkg.Size; OnDownloadProgressChanged(new PackageDownloadProgressChangedEventArgs(pkg, pkg.Size, pkg.DownloadedSize, e.ProgressPercentage)); }; workers.Add(client); } //开始处理事务 while (!hasError) { var breakFlag = false; lock (Packages) { //没有错误,则分配下个任务 WebClient client; while ((client = workers.Find(s => !s.IsBusy)) != null) { var nextPkg = Packages.Find(s => !s.IsDownloading && !s.IsDownloaded); if (nextPkg == null) { breakFlag = true; break; } nextPkg.IsDownloading = true; Trace.TraceInformation($"包【{nextPkg.Name}】开始下载"); OnPackageDownload(new PackageEventArgs(nextPkg)); Context.ResetWebClient(client); client.DownloadFileAsync(new Uri(Context.GetUpdatePackageFullUrl(nextPkg.Name)), nextPkg.LocalSavePath, nextPkg); } } if (breakFlag) { break; } evt.WaitOne(); Trace.TraceInformation("线程同步事件已收到"); } //不管任何原因中止下载,到这里时都需要等待所有客户端中止 while (true) { //出错了,那么对所有的客户端发出中止命令。这里不需要判断是否忙碌。 if (hasError) { Trace.TraceWarning("出现错误,正在取消所有包的下载队列"); workers.ForEach(s => s.CancelAsync()); } lock (Packages) { Trace.TraceInformation("等待下载队列完成操作"); if (workers.FindIndex(s => s.IsBusy) == -1) { break; } } evt.WaitOne(); } Trace.TraceInformation("完成下载网络更新包"); var errorPkgs = Packages.FindAll(m => m.LastError != null); if (errorPkgs.Count > 0) { throw new PackageDownloadException(errorPkgs.ToArray()); } return(!hasError); }