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Question

I have a bit of a pickle. There are a list of images I want to grab on a website. I know how to do that much, but I have to filter out the location of the images.

Such as I'd want to grab the images in a div tag with an id "theseImages", but there are another set of images within another div tag with an id called "notTheseImages". Looping through every tag into ah HtmlElementCollection with the tag "img" would ignore the divs, because it'd also grab the images from "notTheseImages."

Is there a way I could loop through the images while doing a check to see where those images are located in the div tags?

Answer 1

This could help you to do the selection of your current HTML and maybe for future occassions :)

protected HtmlElement[] GetElementsByParent(HtmlDocument document, HtmlElement baseElement = null, params string[] singleSelectors)
{
    if (singleSelectors == null || singleSelectors.Length == 0)
    {
        throw new Exception("Please give at least 1 selector!");
    }
    IList<HtmlElement> result = new List<HtmlElement>();
    bool last = singleSelectors.Length == 1;
    string singleSelector = singleSelectors[0];
    if (string.IsNullOrWhiteSpace(singleSelector) || string.IsNullOrWhiteSpace(singleSelector.Trim()))
    {
        return null;
    }
    singleSelector = singleSelector.Trim();
    if (singleSelector.StartsWith("#"))
    {
        var item = document.GetElementById(singleSelector.Substring(1));
        if (item == null)
        {
            return null;
        }
        if (last)
        {
            result.Add(item);
        }
        else
        {
            var results = GetElementsByParent(document, item, singleSelectors.Skip(1).ToArray());
            if (results != null && results.Length > 0)
            {
                foreach (var res in results)
                {
                    result.Add(res);
                }
            }
        }
    }
    else if (singleSelector.StartsWith("."))
    {
        if (baseElement == null)
        {
            baseElement = document.Body;
        }
        foreach (HtmlElement child in baseElement.Children)
        {
            string cls;
            if (!string.IsNullOrWhiteSpace((cls = child.GetAttribute("class"))))
            {
                if (cls.Split(' ').Contains(singleSelector.Substring(1)))
                {
                    if (last)
                    {
                        result.Add(child);
                    }
                    else
                    {
                        var results = GetElementsByParent(document, child, singleSelectors.Skip(1).ToArray());
                        if (results != null && results.Length > 0)
                        {
                            foreach (var res in results)
                            {
                                result.Add(res);
                            }
                        }
                    }
                }
            }
        }
    }
    else
    {
        HtmlElementCollection elements = null;

        if (baseElement != null)
        {
            elements = baseElement.GetElementsByTagName(singleSelector);
        }
        else
        {
            elements = document.GetElementsByTagName(singleSelector);
        }
        foreach (HtmlElement item in elements)
        {
            if (last)
            {
                result.Add(item);
            }
            else
            {
                var results = GetElementsByParent(document, item, singleSelectors.Skip(1).ToArray());
                if (results != null && results.Length > 0)
                {
                    foreach (var res in results)
                    {
                        result.Add(res);
                    }
                }
            }
        }
    }
    return result.ToArray();
}

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
    // here we can query
    var result = GetElementsByParent(webBrowser1.Document, null, "#theseImages", "img");
}

result would then contain the images that are under #theseImages

Mind you the GetElementsByParent is fairly untested, I just tested it for your use case and it seemed to be ok.

Don't forget to only start the query once you are sure the document is completed ;)