How to get the value from a background worker

while (i <= 1000) {
   // ...
   e.Result = a;
   backgroundWorker1.ReportProgress(i);
}

// During initialization:
backgroundWorker1.ReportProgress += backgroundWorker1_ProgressChanged;

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
   // You will get the current index with
   int index = e.ProgressPercentage;
}

public class Form1
{
int i =0;
public Form1()
        {
            InitializeComponent();
           backgroundWorker1.RunWorkerAsync();
 
        }
 
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
 
            
            DateTime a;
            while ( i <= 1000)
            {
                a = DateTime.Now;
                if (i == 999)
                {
                    i = 0;
 
                }
                e.Result = a;
 
          }
 
        }
       private void btnShowIndex_Click(object sender, EventArgs e)
        {
           label.Text = i.ToString();
        }
}