I am having an issue with navigation. I get a list of rows from an html table. I iterate over the rows and scrape information from them. But there is also a link on the row that I click to go to more information related to the row to scrape. Then I navigate back to the page with the original table. This works for the first row, but for the subsequent rows, it throws an exception.

I look at my row collection after the first time the link inside a row is clicked, and none of them have the correct values like they did before I clicked the link. I believe that there is something going on when I navigate to a different URL that I'm not getting.

My code is below. How do I get this working so I can iterate over the parent table, click the links in each row, navigate to the child table, but still continue iterating over the rows in the parent table?

    private List<Document> getResults()
    {
        var documents = new List<Document>();

        //Results
        IWebElement docsTable = this.webDriver.FindElements(By.TagName("table"))
            .Where(table => table.Text.Contains("Document List"))
            .FirstOrDefault();

        var validDocRowRegex = new Regex(@"^(\d{3}\s+)");

        var docRows = docsTable.FindElements(By.TagName("tr"))
            .Where(row =>
                //It throws an exception with .FindElement() when there isn't one.
                row.FindElements(By.TagName("td")).FirstOrDefault() != null &&
                    //Yeah, I don't get this one either. I negate the match and so it works??
                !validDocRowRegex.IsMatch(
                    row.FindElement(By.TagName("td")).Text))
            .ToList();

        foreach (var docRow in docRows)
        {
            //Todo: find out why this is crashing on some documents.
            var cells = docRow.FindElements(By.TagName("td"));

            var document = new Document
            {
                DocID = Convert.ToInt32(cells.First().Text),
                PNum = Convert.ToInt32(cells[1].Text),
                AuthNum = Convert.ToInt32(cells[2].Text)
            };

            //Go to history for the current document.
            cells.Where(cell =>
                cell.FindElements(By.TagName("a")).FirstOrDefault() != null)
                .FirstOrDefault().Click();

            //Todo: scrape child table.

            this.webDriver.Navigate().Back();
        }

        return documents;
    }