使用BackgroundWorker C＃后冻结应用程序

Question

I read data from file and write them in other file. I want show user number of read lines with label. It working. And user can stop reading. I use backgroundworke, but the application does not respond to the Stop button-is frozen. I tried Aplication.DoEvents(), But I must just need to button 2x to respond.

start reading

private void button1_Click(object sender, EventArgs e)
{
    string ext = Path.GetExtension(openFileDialog1.FileName);
    if (ext == ".arff")
    {
        getColumn();
        backgroundWorker1.RunWorkerAsync();
    }
}

reading and writing

private void readDataArffBig()
{            
    int lines = 0;
    StreamWriter sw = new StreamWriter(tempFile, true);
    using (StreamReader sr = new StreamReader(openFileDialog1.FileName))
    {
        while ((line = sr.ReadLine()) != null)
        {
            lines++;
            backgroundWorker1.ReportProgress(lines);
            if (status == false)
                break;
            sw.WriteLine(line)}
        }
}

stop reading set status to false..berofe is true

private void stop_Click(object sender, EventArgs e)
{
    status = false;           
}

BW use

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    readDataArffBig();
}

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
    label8.Text = e.ProgressPercentage.ToString();
    label8.Refresh();
}

Answer 1

First of all, are you setting your BackgroundWorker to allow cancellation?

backgroundWorker1.WorkerSupportsCancellation = true;

Then your Do_Work event should look something like this:

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
     BackgroundWoker bgw = sender as BackgroundWorker;
    if(bgw.CancellationPending)
    {
       e.Cancel = true;
       return;
    }
    else
    {
      readDataArffBig();
    }
}

***EDIT

private void stop_Click(object sender, EventArgs e)
    {
         backgroundWorker1.CancelAsync();
        //status = false;           
    }

Answer 2

In addition to the changes proposed by SOfanatic, and as suggested by mike z, you should be checking for the pending cancellation in readDataArffBig(). A good place would be right in the while statement:

while (((line = sr.ReadLine()) != null) && (!backgroundWorker1.CancellationPending))