title: BackgroundWorker is currently busy and can not run multiple tasks concurrently
body: <p>I am trying to iterate an array while using backgroundworker, I am sure it is just my syntax being incorrect, but I am constantly getting the error.  Can someone assist me with what to do to rectify this?</p>
  
  <pre><code>namespace Form1
  {
  public partial class Form1 : Form
  {
      public BackgroundWorker backgroundWorker1 = new BackgroundWorker();
      public OpenFileDialog fd = new OpenFileDialog();
  
      public Form1()
      {
          InitializeComponent();
          backgroundWorker1.WorkerReportsProgress = true;
          backgroundWorker1.WorkerSupportsCancellation = true;
          backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
          backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
      }
      private void btn_Two_Click(object sender, EventArgs e)
      {
          fd.Title = "Select The Text File To Open";
          fd.Filter = "Text Files|*.txt";
          fd.InitialDirectory = @"C:\";
          if (fd.ShowDialog() == DialogResult.OK)
          {
              TextFiles(sender);
          }
      }
      private void TextFiles(object sender)
      {
          IEnumerable&lt;String&gt; employeeNames = File.ReadLines(fd.FileName);
          foreach (string pgs in employeeNames)
          {
              employee = pgs;
              ProcessTables(employee, sender);
          }
      }
      private void ProcessTables(string employee, object sender)
      {
          sw.Restart();
          timer.Start();
          //This line is where the compiler throws the error
          backgroundWorker1.RunWorkerAsync();            
      }
      private void backgroundworker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
      {
        progressBar1.Value = e.ProgressPercentage;
      }
      private void backgroundworker1_DoWork(object sender, DoWorkEventArgs e)
      {
        //Never hits this block so I will omit this code for time sake
      }
  }
  }
  </code></pre>