C# downloadasync 等待下载完成

Question

是否可以等待下载完成再执行下一行代码？

WebClient wb = new WebClient();
wb.DownloadFileAsync(new Uri("url"), @"c:\tmp\file.exe");
wb.DownloadProgressChanged += wb_DownloadProgressChanged;
wb.DownloadFileCompleted += wb_DownloadFileCompleted;
//Code to run after download finished...

我知道我可以只使用 wb.DownloadFile 但这不会提供有关下载百分比的反馈。

Answer 1

如果您使用的是 .net 4.5，则可以利用新的 async/await 关键字和 DownloadFileTaskAsync方法

async void DownloadSomeFile()
{
   WebClient wb = new WebClient();
   wb.DownloadProgressChanged += wb_DownloadProgressChanged;
   wb.DownloadFileCompleted += wb_DownloadFileCompleted;

   await wb.DownloadFileTaskAsync(new Uri("url"), @"c:\tmp\file.exe");

   //Do the other work here
}