Develop Reference

What is the fastest way to get an HTML document node using XPath and the HtmlAgilityPack?

In my application I need to get to get the URL of the image of a blog post. In order to do this I'm using the HtmlAgilityPack.
This is the code I have so far:
static string GetBlogImageUrl(string postUrl)
{
string imageUrl = string.Empty;
using (WebClient client = new WebClient())
{
string htmlString = client.DownloadString(postUrl);
HtmlDocument htmlDocument = new HtmlDocument();
htmlDocument.LoadHtml(htmlString);
string xPath = "/html/body/div[contains(#class, 'container')]/div[contains(#class, 'content_border')]/div[contains(#class, 'single-post')]/main[contains(#class, 'site-main')]/article/header/div[contains(#class, 'featured_image')]/img";
HtmlNode node = htmlDocument.DocumentNode.SelectSingleNode(xPath);
imageUrl = node.GetAttributeValue("src", string.Empty);
}
return imageUrl;
}
The problem is that this is too slow, when I did some tests I noticed that It takes about three seconds to extract the URL of the image in the given page. Which it's a problem when I'm loading a feed and trying to red several articles.
I tried to use the absolute xpath of the element I want to load, but I didn't noticed any improvement. Is there a faster way to achieve this?

Can you try this code and see if it's faster or not?
string Url = "http://blog.cedrotech.com/5-tendencias-mobile-que-sua-empresa-precisa-acompanhar/";
HtmlWeb web = new HtmlWeb();
HtmlDocument doc = web.Load(Url);
var featureDiv = doc.DocumentNode.Descendants("div").FirstOrDefault(_ => _.Attributes.Contains("class") && _.Attributes["class"].Value.Contains("featured_image"));
var img = featureDiv.ChildNodes.First(_ => _.Name.Equals("img"));
var imgUrl = img.Attributes["src"];

How to get specific part of webpage in mvc?

I want to get a specific part of current page to save it in another file for example in a PDF file.
I want to get this part of current view in ActionResult when I click on submit:
<div id="t1" name="t1">
.......
</div>
I tried to use this code to get :
client = new WebClient();
string url = HttpContext.Request.Url.AbsoluteUri;
string content = "";
Stream data = client.OpenRead(url);
StreamReader sr = new StreamReader(data);
content = sr.ReadToEnd();
data.Flush();
data.Close();
But I want to get only tag div named t1 from current page.
NOTE: I don't want to use jquery. I only want to do it in C#.

try using HTMLAgilityPack for this sort of thing...
example code block;
public string GetContent(string url)
{
HtmlWeb hw = new HtmlWeb();
HtmlDocument doc = hw.Load(url);
HtmlNode node = doc.DocumentNode.SelectSingleNode("//div[#id='t1']");
return node.InnerHtml;
}

How to get hidden InnerHtml of web page that set by javascript?

I know that I can get source of web page with this code:
browser.DocumentText;
some data of page filled by javascript innetHtml function and will not visible in browser.Text but in browser's output is visible.
How can I get source code of data that added by javascript to page?

If you know what type of tag contains the inner HTML you want to get at, you could do something like this (this example loops through the div tags, but you could do p, or table cells, or whatever):
HtmlElementCollection collection = browser.Document.GetElementsByTagName("div");
foreach (HtmlElement element in collection) {
string html = element.InnerHtml;
string text = element.InnerText;
// do something with the HTML or text here...
}
Or if you know the specific ID of the element you want to get, use:
HtmlElement element = browser.Document.GetElementById("someId123");
if(null != element) // do something with it...

You could give HtmlAgilityPack a try and follow this answer.
HtmlWeb webGet = new HtmlWeb();
HtmlAgilityPack.HtmlDocument doc = webGet.Load(url);

Extract image sources from a web page, where img tags might be added when the page is rendered by javascript etcq

I want to extract the "" of all the images in a web page in C#/asp.net.
I am using:
WebClient client = new WebClient();
string mainSource = client.DownloadString(URL);
and searching mainSource string for "".
This method seems to work correctly, but only if all the images(" tags) are present in raw source code of the web page.
The image tags rendered by javascript etc are not being scanned in the above process.
Is there another way to do this?

Try this out
HtmlWeb hw = new HtmlWeb();
HtmlDocument doc = hw.Load(/* url */);
foreach(HtmlNode link in doc.DocumentElement.SelectNodes("//img[#src]"))
{
}

Can i read iframe through WebClient (i want the outer html)?

Well my program is reading a web target that somewhere in the body there is the iframe that i want to read.
My html source
<html>
...
<iframe src="http://www.mysite.com" ></iframe>
...
</html>
in my program i have a method that is returning the source as a string
public static string get_url_source(string url)
{
using (WebClient client = new WebClient())
{
return client.DownloadString(url);
}
}
My problem is that i want to get the source of the iframe when it's reading the source, as it would do in normal browsing.
Can i do this only by using WebBrowser Class or there is a way to do it within WebClient or even another class?
The real question:
How can i get the outer html given a url? Any appoach is welcomed.

After getting the source of the site, you can use HtmlAgilityPack to get the url of the iframe
HtmlAgilityPack.HtmlDocument doc = new HtmlAgilityPack.HtmlDocument();
doc.LoadHtml(html);
var src = doc.DocumentNode.SelectSingleNode("//iframe")
.Attributes["src"].Value;
then make a second call to get_url_source

Parse your source using HTML Agility Pack and then:
List<String> iframeSource = new List<String>();
HtmlDocument doc = new HtmlDocument();
doc.Load(url);
foreach (HtmlNode node in doc.DocumentElement.SelectNodes("//iframe"))
iframeSource.Add(get_url_source(mainiFrame.Attributes["src"]));
If you are targeting a single iframe, try to identify it using ID attribute or something else so you can only retrieve one source:
String iframeSource;
HtmlDocument doc = new HtmlDocument();
doc.Load(url);
foreach (HtmlNode node in doc.DocumentElement.SelectNodes("//iframe"))
{
// Just an example for check, but you could use different approaches...
if (node.Attributes["id"].Value == 'targetframe')
iframeSource = get_url_source(node.Attributes["src"].Value);
}

Well i found the answer after some search and this is what i wanted
webBrowser1.Url = new Uri("http://www.mysite.com/");
while (webBrowser1.ReadyState != WebBrowserReadyState.Complete) Application.DoEvents();
string InnerSource = webBrowser1.Document.Body.InnerHtml;
//You can use here OuterHtml too.