为什么使用了BackgroundWorker，还是很卡，界面还是出现未响应
大家帮我看看了，不知道哪里出问题，应该如何修改？
BackgroundWorker bw = null;
public Form3()
{
InitializeComponent();
bw = new BackgroundWorker();
bw.WorkerSupportsCancellation = true;
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
}
void bw_DoWork(object sender, DoWorkEventArgs e)
{
for (int i = 1; i < 100; i++)
{
if (bw.CancellationPending)
{
e.Cancel = true;
break;
}
this.Invoke((MethodInvoker)delegate
{
this.richTextBox1.Text += Environment.NewLine + String.Format("第{0}次测试是否联网：{1}", i.ToString(), IsWWW("http://www.baidu.com"));
Thread.Sleep(2000);
});
}
}
void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
this.richTextBox1.Text += "执行完毕";
}
private void button1_Click(object sender, EventArgs e)
{
this.button1.Enabled = false;
bw.RunWorkerAsync();
}
private void button2_Click(object sender, EventArgs e)
{
this.button1.Enabled = true;
this.button2.Enabled = false;
bw.CancelAsync();
}
private void richTextBox1_TextChanged(object sender, EventArgs e)
{
RichTextBox textbox = (RichTextBox)sender;
textbox.SelectionStart = textbox.Text.Length;
textbox.ScrollToCaret();
}
private bool IsWWW(string url)
{
try
{
new WebClient().DownloadString(url);
return true;
}
catch (Exception ex)
{
return false;
}
}
