Question

Essentially, I have a Do..While loop going through some lines from a text file. I want to process a line, return a value (worked or didn’t), then move to the next line.

I have a function called ProcessTXT that accepts 2 strings. Source and Destination of new file.

Is there a way to set a ReturnedValue string = to the result and have the backgroundworker check to see if the variable changed? And if so, add this value to the list box?

private void TranslatePOD(string strSource, string strDest,)
{
  TextWriter tw = new StreamWriter(strDest);
  TextReader tr = new StreamReader(strSource);
  do
    {
      //My Code doing stuff
      //Need to send a result somehow now, but i have more work to do in this loop
      //Then using tw.writeline() to write my results to my new file
    } while (tr.ReadLine() != null);
}

EDIT: Current test code using Yield. My output is “TestingGround.Form1+d__0”. Did i do something wrong?

namespace TestingGround
{
public partial class Form1 : Form
{
    static IEnumerable<string> TestYield(string strSource) 
    {
        TextReader tr = new StreamReader(strSource);
        string strCurLine = System.String.Empty;

        while ((strCurLine = tr.ReadLine()) != null)
        {
            yield return strCurLine;
        }
    }

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        string MySource = System.String.Empty;
        MySource = @"C:\PODTest\Export Script\Export\Shipment List.csv";
        listBox1.Items.Add(TestYield(MySource));

    }
}

Answer 1

Yield is typically used to return results iteratively, or streaming. There are plenty of examples online. There’s one on SO for reading in a file.