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VS 2008 SP1

我正在使用 DownloadStringAysnc。但是 ProgressChanged 事件直到字符串下载后才会显示进度。

即使我尝试下载包含在大文件中的字符串。这些程序仍然响应，所以我知道它正在做某事。但是，进度完成时才会触发 progressChanged 事件。

我将其称为 progressChanged 和 DownloadStringCompleted 紧随其后。但是，由于文件很大，因此应该暂停。

这是我目前正在使用的代码片段。以及下面的输出。奇怪的是 e.progresspercentage 是 100%。并且似乎被调用了两次。

非常感谢您的任何建议，

Output in the progress changed event
Progress changed Version userstate: [ Version1 ]
progressBar1.Value [ 100 ]
Progress changed Version userstate: [ Version1 ]
progressBar1.Value [ 100 ]
Completed Version userstate: [ Version1 ]


private void UpdateAvailable()
        {
            WebClient wbCheckUpdates = new WebClient();
            wbCheckUpdates.DownloadProgressChanged += new DownloadProgressChangedEventHandler(wbCheckUpdates_DownloadProgressChanged);
            wbCheckUpdates.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wbCheckUpdates_DownloadStringCompleted);
            DownloadFiles df = new DownloadFiles();
            string webServerURL = df.webServerPath;

            wbCheckUpdates.DownloadStringAsync(new Uri(Path.Combine(webServerURL, "version.txt")), "Version1"); 
        }




void wbCheckUpdates_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
        {
            Console.WriteLine("Progress version changed userstate: [ " + e.UserState + " ]");
            progressBar1.Value = e.ProgressPercentage;
            Console.WriteLine("progressBar1.Value [ " + this.progressBar1.Value + " ]");
        }

void wbCheckUpdates_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
            Console.WriteLine("Completed version userstate: [ " + e.UserState + " ]");
        }

=========== 使用 DownloadDataAysnc 编辑 ===============

wbCheckUpdates.DownloadDataAsync(new Uri(Path.Combine(webServerURL, "version.txt")), "Version1");


void wbCheckUpdates_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
        {
            byte[] result = e.Result;           
            Console.WriteLine("Completed data: [ " + System.Text.ASCIIEncoding.Default.GetString(result) + " ]");
        }

结果是一样的：

Progress changed Version userstate: [ Version1 ]
progressBar1.Value [ 100 ]
Progress changed Version userstate: [ Version1 ]
progressBar1.Value [ 100 ]
Completed data: [ 1.0.11 ]
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1 回答 1

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根据文档，DownloadStringAsync 不报告进度。请参阅WebClient.DownloadProgressChanged 事件的文档。

于 2009-08-01T13:38:37.437 回答