我的主要问题是，当我在 flowLayoutPanel1 上为每个请求动态添加进度条时，如何从backgroundWorker1_ProgressChanged 事件中增加正确的进度条值
当用户单击开始按钮时，我将调用后台工作者的 RunWorkerAsync 函数....很好。在这里，我正在编写示例代码并尝试显示我的问题。
我的表单有一个文本框、一个按钮和一个带有 FlowDirection 自上而下的 flowLayoutPanel1。
当用户在文本框中输入任何 url 并单击开始按钮时，我将使用 BackGroundWorker 开始文件下载，并在 flowLayoutPanel1 上动态添加一个进度条。一次可以下载10个文件。因此，当用户一个接一个地输入十个网址并单击提交按钮时，十个文件将在后台下载。
我的问题是如何从 backgroundWorker1_ProgressChanged 事件中正确增加 10 个进度条进度另一个问题是当任何文件下载完成时，已创建它的进度条将从面板中删除
这是我的完整代码。请看看并告诉我我需要做什么来完成我的任务。如果有人看到我的代码中可能出现死锁的问题，那么也请指导我如何避免死锁。这是我的代码
public partial class Form1 : Form
{
static int pbCounter = 1;
public Form1()
{
InitializeComponent();
}
private void btnStart_Click(object sender, EventArgs e)
{
ProgressBar pb = new ProgressBar();
if (pbCounter <= 10)
{
pb.Width = txtUrl.Width;
flowLayoutPanel1.Controls.Add(pb);
pbCounter++;
System.ComponentModel.BackgroundWorker backgroundWorker1 = new System.ComponentModel.BackgroundWorker();
backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
backgroundWorker1.RunWorkerAsync();
}
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
// Get the BackgroundWorker that raised this event.
System.ComponentModel.BackgroundWorker worker = sender as System.ComponentModel.BackgroundWorker;
// Assign the result of the computation
// to the Result property of the DoWorkEventArgs
// object. This is will be available to the
// RunWorkerCompleted eventhandler.
//#e.Result = ComputeFibonacci((int)e.Argument, worker, e);
}
// This event handler deals with the results of the
// background operation.
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
// First, handle the case where an exception was thrown.
if (e.Error != null)
{
MessageBox.Show(e.Error.Message);
}
else if (e.Cancelled)
{
//# "Canceled";
}
else
{
pbCounter--;
// Finally, handle the case where the operation
// succeeded.
//#resultLabel.Text = e.Result.ToString();
}
}
// This event handler updates the progress bar.
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
this.progressBar1.Value = e.ProgressPercentage;
}
}
我更新的部分
public partial class Form1 : Form
{
static int pbCounter = 1;
public Form1()
{
InitializeComponent();
}
private void btnStart_Click(object sender, EventArgs e)
{
ProgressBar pb = new ProgressBar();
if (pbCounter <= 10)
{
//pb.Step = 10;
pb.Minimum = 0;
//pb.Maximum = 100;
pb.Width = txtUrl.Width;
flowLayoutPanel1.Controls.Add(pb);
pbCounter++;
MyBackgroundWorker backgroundWorker1 = new MyBackgroundWorker();
backgroundWorker1.pbProgress = pb;
backgroundWorker1.WorkerReportsProgress = true;
backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);
backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
backgroundWorker1.RunWorkerAsync(txtUrl.Text);
}
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
int input = int.Parse(e.Argument.ToString());
for (int i = 1; i <= input; i++)
{
Thread.Sleep(2000);
(sender as MyBackgroundWorker).ReportProgress(i * 10);
if ((sender as MyBackgroundWorker).CancellationPending)
{
e.Cancel = true;
return;
}
}
}
// This event handler deals with the results of the
// background operation.
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
// First, handle the case where an exception was thrown.
if (e.Error != null)
{
MessageBox.Show(e.Error.Message);
}
else if (e.Cancelled)
{
//# "Canceled";
}
else
{
ProgressBar pb = (sender as MyBackgroundWorker).pbProgress;
if (pb != null)
{
//pb.Value = 100;
//pb.Update();
while (pb.Value <= pb.Maximum)
{
//Thread.Sleep(1000);
flowLayoutPanel1.Controls.Remove(pb);
break;
}
}
// Finally, handle the case where the operation
// succeeded.
}
}
// This event handler updates the progress bar.
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
ProgressBar pb = (sender as MyBackgroundWorker).pbProgress;
pb.Refresh();
//if (e.ProgressPercentage < pb.Maximum)
// pb.Value = e.ProgressPercentage + 10;
pb.Value = e.ProgressPercentage ;
Application.DoEvents();
}
}
public class MyBackgroundWorker : System.ComponentModel.BackgroundWorker
{
public ProgressBar pbProgress = null;
public MyBackgroundWorker()
{
}
public MyBackgroundWorker(string name)
{
Name = name;
}
public string Name { get; set; }
}