我有一个启动后台工作的按钮:
private void button1_Click(object sender, EventArgs e)
{
backgroundWorker1.RunWorkerAsync();
button1.Enabled = false;
button2.Enabled = true;
}
取消后台工作人员的按钮:
private void button2_Click(object sender, EventArgs e)
{
backgroundWorker1.CancelAsync();
button1.Enabled = true;
button2.Enabled = false;
}
backgroundworker dowork.progresschanged.completed events:
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker bgw = (BackgroundWorker)sender;
if (bgw.CancellationPending == true)
{
return;
}
else
{
Parseanddownloadfiles();
}
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
lblStatus.Text = "Downloading Filename: " + e.UserState.ToString();
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
stopwatch.Stop();
}
最后一个方法Parseanddownloadfiles()
private void Parseanddownloadfiles()
{
using (WebClient client = new WebClient())
{
client.DownloadFile(mainurl, path_exe + "\\page.html");
}
HtmlAgilityPack.HtmlWeb hw = new HtmlAgilityPack.HtmlWeb();
HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
doc = hw.Load(path_exe + "\\page.html");
foreach (HtmlAgilityPack.HtmlNode link in doc.DocumentNode.SelectNodes("//a[@href]"))
{
string hrefValue = link.GetAttributeValue("href", string.Empty);
if (hrefValue.Contains("US"))
{
string url = "http://www.testing.com" + hrefValue;
parsedlinks.Add(url);
}
}
for (int i = 0; i < parsedlinks.Count; i++)
{
try
{
using (WebClient client = new WebClient())
{
string filename = parsedlinks[i].Substring(71);
client.DownloadFile(parsedlinks[i], filesdirectory + "\\" + filename);
backgroundWorker1.ReportProgress(0, filename);
}
}
catch (Exception err)
{
string error = err.ToString();
}
}
}
现在重要的是让取消工作,然后是否可以在之后暂停/继续。
答案 0 :(得分:0)
更改方法int以检查循环内的条件:
private void Parseanddownloadfiles()
{
using (WebClient client = new WebClient())
{
client.DownloadFile(mainurl, path_exe + "\\page.html");
}
HtmlAgilityPack.HtmlWeb hw = new HtmlAgilityPack.HtmlWeb();
HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
doc = hw.Load(path_exe + "\\page.html");
foreach (HtmlAgilityPack.HtmlNode link in doc.DocumentNode.SelectNodes("//a[@href]"))
{
string hrefValue = link.GetAttributeValue("href", string.Empty);
if (hrefValue.Contains("US"))
{
string url = "http://www.testing.com" + hrefValue;
parsedlinks.Add(url);
}
if (bgw.CancellationPending == true)
return;
}
for (int i = 0; i < parsedlinks.Count && bgw.CancellationPending == false; i++)
{
try
{
using (WebClient client = new WebClient())
{
string filename = parsedlinks[i].Substring(71);
client.DownloadFile(parsedlinks[i], filesdirectory + "\\" + filename);
backgroundWorker1.ReportProgress(0, filename);
}
}
catch (Exception err)
{
string error = err.ToString();
}
}
如果您需要取消下载,我最喜欢的解决方案是使用一些任务和CancellationTokenSource。
此致