Question

This is how i call that error given function

    var CrawlPage = Task.Factory.StartNew(() =>
{
    return crawlPage(srNewCrawledUrl);
});

var GetLinks = CrawlPage.ContinueWith(resultTask =>
{
    if (CrawlPage.Result == null)
    {
        return null;
    }
    else
    {
        return ReturnLinks(CrawlPage.Result, srNewCrawledUrl, srNewCrawledPageId);
    }

});

This is the error i really don’t understand how is that possible. I am using local assigned variables so variables should be thread safe for all threads. Am i incorrect ?

this is the error image :

Answer 1

you better validate InnerHtml is null or not before calling

var GetLinks = CrawlPage.ContinueWith(resultTask =>
{
    if (CrawlPage.Result == null || CrawlPage.Result.DocumentNode == null ||  CrawlPage.Result.DocumentNode.InnerHtml == null)
    {
        return null;
    }
    else
    {
        return ReturnLinks(CrawlPage.Result, srNewCrawledUrl, srNewCrawledPageId);
    }

});

Or check this on ReturnLinks method