I have googled this with a couple of differing terms and I could not find my solution. What I want to do is to manipulate a webpage by editing its source, for example removing a part from the code maybe a div or so. I know how to get the source of a webpage and know how to change the code but I have no idea how to manipulate the page instantly, by for example removing an element.
Your help would be appreciated!
If you want to manipulate client code (HTML) what you need is Ajax.
You can use JQuery javascript library to manipulate html of a page adding, editing and removing html tags, scripts, etc.
Here you can find a decent tutorial as a start point.
If you want to manipulate server code (C# codebehind) what you need is creating a web project in visual studio (ASP.NET Web Application)
EDIT: As commented by #CSharpened both solutions are not mutual exclusive. You can have an ASP.NET Web application that uses Ajax to manipulate UI. In fact lot of people does that.
I would consider using AJAX. You can use either javascript or jquery coupled with html, asp.net and C# to achieve the results you are after.
For simple editing like removing divs or collapsing menus etc simple Javascript or jquery will suffice. However changing the coding of the page requires you to use AJAX or similar.
Related
I am using the Nancy Web Framework in my C# Console Application to basically create a Web Administration panel for my software. I have opted to use the Spark View Engine, as it is basically just HTML. I basically want to create a chatbox, except pull the data written to my application's console every X seconds and display it in a box instead.
I have very little experience with JQuery and AJAX, but they aren't overly complicated from the examples I have seen. The issue I am running into is that ALL of the chatbox and shoutbox examples use PHP.
I basically just need something like this...
The only difference is I need to pull the information from my application instead. I can use basic C# methods inside of the HTML (and probably inside of javascript but I haven't tried this). What would be the best way to do this, and are there any examples floating around that don't use PHP?
This was completed using AJAX and JSON.
Well, to use HTML for styling inside some PC program is just not wise. It has much better UI engines, though. But for your information here is nice jQuery shoutbox tutorial, but well, you only need to handle data input and output with C#, so actually I see no problems. The engine which you are using should have some kind of data stream, or requests handler (bla://program/???)
I have been given a task to crawl / parse and index available books on many library web page. I usually use HTML Agility Pack and C# to parse web site content. One of them is the following:
http://bibliotek.kristianstad.se/pls/bookit/pkg_www_misc.print_index?in_language_id=en_GB
If you search for a * (all books) it will return many lists of books, paginated by 10 books per page.
Typical web crawlers that I have found fail on this website. I have also tried to write my own crawler, which would go through all links on the page and generate post/get variables to dynamically generate results. I havent been able to do this as well, mostly due to some 404 errors that I get (although I am certain that the links generated are correct).
The site relies on javascript to generate content, and uses a mixed mode of GET and POST variable submission.
I'm going out on a limb, but try observing the JavaScript GETs and POSTs with Fiddler and then you can base your crawling off of those requests. Fiddler has FiddlerCore, which you can put in your own C# project. Using this, you could monitor requests made in the WebBrowser control and then save them for crawling or whatever, later.
Going down the C# JavaScript interpreter route sounds like the 'more correct' way of doing this, but I wager it will be much harder and frought with errors and bugs unless you have the simplest of cases.
Good luck.
FWIW, the C# WebBrowser control is very, very slow. It also doesn't support more than two simultaneous requests.
Using SHDocVw is faster, but is also semaphore limited.
Faster still is using MSHTML. Working code here: https://svn.arachnode.net/svn/arachnodenet/trunk/Renderer/HtmlRenderer.cs Username/Password: Public (doesn't have the request/rendering limitations that the other two have when run out of process...)
This is headless, so none of the controls are rendered. (Faster).
Thanks,
Mike
If you use the WebBrowser control in a Windows Forms application to open the page then you should be able to access the DOM through the HtmlDocument. That would work for the HTML links.
As for the links that are generated through Javascript, you might look at the ObjectForScripting property which should allow you to interface with the HTML page through Javascript. The rest then becomes a Javascript problem, but it should (in theory) be solvable. I haven't tried this so I can't say.
If the site generates content with JavaScript, then you are out of luck. You need a full JavaScript engine usable in C# so that you can actually execute the scripts and capture the output they generate.
Take a look at this question: Embedding JavaScript engine into .NET -- but know that it will take "serious" effort to do what you need.
AbotX does javascript rendering for you. Its not free though.
I realize this is probably a fundamental thing I should know but I am self-teaching myself C# and asp.net so I am a little lost at this point.
I right now have 2 pages. One is an .aspx (with aspx.cs file included) that is blank and html is generated for it from a Page_Load function in the cs file. The HTML is very simple and it is just an image and some text.
The second file is a shtml file which has lots of things, serverside includes, editable and noneditable areas. I want to put my webapp into this file. My asp.net app uses Response.Write to just write out the html. This does not flow well with this page as all that does is write it at the top of the page which is because it is ran first and generates it at the top.
How can I make it to where I can generate HTML code inside the page, like within a specific DIV so it does not mess up the page. Where would a starting point be in learning how to do that.
I should note that I do not need any interaction from the user. All of this should generate right away.
I think you need to read up on some basic ASP.Net documentation and tutorials. Response.Write is not the correct approach - you need to understand how the ASP.Net page lifecycle works and how WebControls are used to render the html.
ASP.Net tries to abstract away having to create your html manually for the most part.
So if i have understood the questions correctly.
You already have an existing page/application (the shtml file) that you want to extend with some new ASP.NET components by including output from the ASP.NET page in the existing page?
This is as not something that is out of the box "supported" by ASP.NET and you "won't" be able to execute the aspx page using SSI. But you can do the opposite, an ASP.NET page does support SSI. So if you are not using any other scripts in the shtml file this might be a solution.
Otherwise the only common solutions would be either to use an AJAX framework and let it call the ASP.NET from within the existing pages or to use an iframe solution. In both cases the client will be resposible for making the calls to the ASP.NET pages and merging the results.
And then you have a issue with controlling the output from the ASP.NET page?
The Polymorphic Podcast has a good article on Controlling HTML in ASP.NET WebForms .
You can add a Literal control to the page inside the div:
<div>
<asp:Literal ID="litMarkup" runat=server />
</div>
then in your code-behind:
litMarkup.Text = "<strong>Your markup</strong>";
I don't know how well this would work for you, but could you try using an iframe to house the ASP.NET page? This should keep it in the specified region and not overwriting your shtml file. It may be something to think about.
If it is necessary that you generate your HTML output from C# code, and you would use this in more than one place, I think you may be thinking of something like what are called ASP.NET Custom Controls (not to be confused with "User Controls"-- though you probably could put together a solution with those as well, using a Literal control as another person suggested). The MSDN documentation would be a good starting point. In general, though, the writing-out-HTML-yourself-from-code model (like you would with, say, CGI applications), is not the usual ASP.NET model of development, as it largely defeats the point of using ASP.NET at all. You'd mostly want to do this sort of thing if you are writing your own web control, though this might be exactly what you are doing (hard to tell from the description).
I was reading an article that shows how bad CodePlex uses UpdatePanels and how nice is StackOverflow on this matter when, for example, a user upvotes an answer/question.
I wonder if someone can point a tutorial on how to do such action.
I know some points:
Create a Web Service that gets the action value and ouputs a JSON string
Build the javascript inside <ajax:ScripManager> control to replace the correct value on the page with the new value
But, even in the first I have difficulties, I can send a JSON string, but it will always be surrounded with XML information!
Can anyone (or maybe Jeff) point to a nice "how-to" since scratch? Thank you.
Well, I doubt StackOverflow uses UpdatePanel - more likely it uses jQuery / load to simply update a div, using ASP.NET MVC as the source (rather than ASP.NET vanilla, which has a more complex page cycle).
With this approach, it is trivial... the jQuery examples tab largely says it all.
Re returning the Json - that is simply return Json(obj); from the controller in ASP.NET MVC - but personally I'd return the html (simpler).
Before you dismiss the UpdatePanel I suggest you have a read of this post I did - http://www.aaron-powell.com/blog/august-2008/optimising-updatepanels.aspx. It looks at how to optimise UpdatePanels and it can lead to some performance increases if done well.
I also did a post - http://www.aaron-powell.com/blog/august-2008/paging-data-client-side.aspx which looks at doing client-side templating with jQuery and MS AJAX. I look at how to read a web service with JavaScript and if you download the sample you'll see how to send data client-side to a web service.
But this video cast on the ASP.NET website may also be of use - http://www.asp.net/learn/ajax-videos/video-82.aspx. It's on how to extend web services for script service capabilities.
how do i make an autocomplete textbox in asp?
but i need to get the autocomplete data by querying the database.
I dont really know how to explain this, sory if theres not enough detail.
i cant use ajax, because i think i will have compability issues with my old app.
so im thinking of doing this using java script. or is there a way to do this by using .net?
im using C# for codebehind. thanks
It's going to be a lot of effort without using some third party autocomplete I think - not sure what you mean by 'I can't use ajax', but how about using the ASP.NET AJAX autocomplete control, setting the ServiceMethod property to a static Page Method in your code behind? That keeps it contained within your page at least.
The Page Method can go off to your database, and return a String[] of results.
If you decide to use it, you'll need to set the EnablePageMethods property to true in the <asp:ScriptManager> control.
AJAX is JavaScript. It's JavaScript using the XMLHttpRequest object to make the asynchronous request. Here's an article about it and ASP.NET.
If you want to know more about AJAX, (Asynchronous JavaScript and XML), I'd check out Wikipedia first. If you want books on it, there are a ton. I recommend Programming ASP.NET AJAX by Christian Wenz (O'Reilly And Associates).
if you dont want to uses ajax library, try jquery
there are many plugin autocomplete or suggest textbox for jquery
try this one
http://www.vulgarisoip.com/2007/08/06/jquerysuggest-11/
The ASP.NET AJAX framework works for ASP.NET 2.0 & above. As such it will not work in Visual Studio 2003 environment.
Anthem.NET is a free, cross-browser AJAX toolkit/framework for the ASP.NET development environment that works with both ASP.NET 1.1 and 2.0 -
http://sourceforge.net/projects/anthem-dot-net
For your autocomplete requirement, you can consider using the jQuery Autocomplete Plugin
It requires very less programming. Check the demo & code sample here - http://docs.jquery.com/Plugins/Autocomplete
It's autocomplete() method takes a URL or array to populate your autocompletion list. You can pass the URL of the page that fetches the results from the database directly.