Question

In my C# app I’m trying to feed into ReadLine() a simple text document with 7 digit strings separated line by line. What I’m attempting to do is grab the next 7 digit string each time the function is called. Here’s what I have so far:

string invoiceNumberFunc()
    {
        string path = @"C:\Users\sam\Documents\GCProg\testReadFile.txt";
        try
        {
            using (StreamReader sr = new StreamReader(path))
            {
                invoiceNumber = sr.ReadLine();

            }

        }
        catch (Exception exp)
        {
            Console.WriteLine("The process failed: {0}", exp.ToString());
        }
       return invoiceNumber;
    }

How do I advance to the next line each time the invoiceNumberFunc() is called?

Thanks in advance.

Answer 1

You’d need to keep hold of the StreamReader between calls, either passing it into the method as a new parameter or making it a member variable of the class.

Personally I prefer the idea of it becoming a parameter, so that it never ends up as a member variable – that makes the life-time easier to manage:

void DoStuff()
{
    string path = @"C:\Users\sam\Documents\GCProg\testReadFile.txt";
    using (StreamReader sr = new StreamReader(path))
    {
        while (keepGoing) // Whatever logic you have
        {
            string invoice = InvoiceNumberFunc(sr);
            // Use invoice
        }
    }
}

string InvoiceNumberFunc(TextReader reader)
{
    string invoiceNumber;
    try
    {
        invoiceNumber = reader.ReadLine();
    }
    catch (Exception exp)
    {
        Console.WriteLine("The process failed: {0}", exp.ToString());
    }
    return invoiceNumber;
}