In my last job we ended up rewriting the complete ASP.NET stack (forms, controls, validation, postback handling, ajax library etc...) - the reason I was given was that the ASP.NET controls were not accessible enough, not were any of the third party controls that were assessed for the project.
Can anyone point me to good accessible ASP.NET controls that do ajax as well?
Failing that, how would you approach creating accessible, ajax enabled controls?
You could take a look at the 'App_Browsers' feature in .NET.
It gives you the opportunity to hook into the rendering engine for each control. The original intention for this was to be able to alter the HTML output of controls depending on the user's browser - but you can also do it for all browsers.
You could also take a look at these control adapters, which make the normal ASP.NET controls 'CSS Friendly'.
Related
I have an ASP.NET custom server control that inherits from the Panel control. It adds its own JavaScript and styles to the page using ScriptManager. Now some users ask me if I can update it so they can use it in MVC. What can be done here? Any references, links, etc would be greatly appreciated.
What can be done here?
Sorry to disappoint you but a total rewrite and re-engineering is required. ASP.NET MVC is an entire different pattern than classic WebForms which relied on server side controls and (may God forbid) ScriptManagers. Depending on what this control is doing and the functionality it exposes there might be different ways to migrate it to MVC. One way would be to use custom Html helpers along with custom jQuery plugins.
I recently tried to create an ASP.Net server control. This server control should has at least two pages. One page for registration (Users can register) and one for asking questions. It is important to make it with ASP.Net Server Control.
The plan is to make this server control and web designers can easily drag and drop this server control into ASP.Net WebForms or MVCs and set properties like back-color or header image in properties tab. I wonder if its possible to have two pages in a server control dll file with all events, viewstates and properties.
Please some one tell me how to create a second page in a server control dll file? And another question is how to move between those pages?
As per my understanding you should go for MultiView or ASP:Wizard control ?
Maybe you are looking something like this from codeproject.
I'm a PHP developer who has to work on ASP.net projects and I'm wondering why every page is wrapped in a form. This just doesn't make sense to me.
Also What's with all the hidden input fields especially the "View State" one.
ASP.Net tries to make it so that the programmers can pretend that the web is a stateful platform, and that it behaves like a desktop application. The ViewState is basically a serialized block of the state of the page when it was generated. When the page gets posted back the server side model gets initialized to the values in ViewState, and then the new values from the posted form are applied.
Part of becoming a decent ASP.Net programmer is learning when to use ViewState and not, because the default is to use it everywhere which causes a lot of bloat in the downloaded page.
Every ASP.NET page is wrapped in a <form> element because the entire framework revolves around POST commands.
ASP.NET provides 'web controls' which are object-oriented abstractions of HTML elements (and in some cases, groups of elements) - in your server-side code you can attach commands to various events on web controls (for example, Button.OnClick, TextBox.OnChanged) - the framework wires these up using a combination of hidden fields and generated javascript. The generated javascript typically sets a hidden field few values to indicate (for example) which control triggered the post and the command arguments (if applicable), then submits the form.
ViewState is a technique used by the framework to serialize client state. It's an alternative to using session heavily, trading larger HTML payloads for a lower memory footprint on the server.
Everything in ASP.NET (aspx pages) works off of posting data.
This means that anything you place on the web page with a server-side action will cause a "post back" to itself. The post back contains information such as "what just happened" and some information that helps the web page to maintain state (which web pages don't traditionally do). The view state is part of that task of maintaining state.
If you don't like the way aspx pages try to turn web-pages into forms-style stateful applications, you can try out the ASP.NET MVC framework, which lets the web work as intended!
ASP.NET WebForms engine creates a stateful abstraction over stateless HTTP.
The key object is a server page. Controls fire events that are processed server-side. Controls maintain their states (usually, input values) between requests.
Any time you click a server control, a "postback" request is sent back to the server. ViewState actually contains the data telling the server what control fired the event. That is why there is always a form (and any more forms are not allowed).
I'm very new to the whole Ajax/Asp.Net stuff so...
I know that there are at least a few different ways of implementing the server-side of an Ajax enabled Asp.Net site.
One way is to add static methods to your aspx page's code-behind and mark them with the WebMethod attribute.
Another way is to use a separate ASMX web service file (which I don't know anything about :) ).
What are the most commonly used options for implementing the server-side? What advantages and drawbacks does each one have? And how does each one fare from a security and session perspective? (Making sure the server knows which session the Ajax request is from and ensuring only logged-in users are responded to?)
Typically I like to use jQuery to make the requests to .ashx page that is responsible for reading the data and passing back the JSON to the page to deal with. It sounds like the other options you suggested are pretty complicated by comparison.
The two most commonly used options are
Microsoft ASP.Net AJAX
JQuery partnered with webservices or request handlers (like Jon's answer)
Microsoft's ASP.Net AJAX is a framework that revolves around two server controls - the ScriptManager and the UpdatePanel. It's a bit more heavyweight than other options, but it's certainly a simple way of ajaxifying your site. You simply use an UpdatePanel to surround the portion of the page that you wish to be asynchronous, and all your controls that do postbacks (buttons, links, etc.) automatically become asynchronous requests that will only update that portion of the page. No coding or anything.
If you do plan on using the webservice route, ASMX is not the way to go - it's basically a "legacy" technology at this point and you should consider using WCF services instead.
I am new to this whole sharepoint and aspx programming. I have developed a sharepoint web part that has a button control. The onclick event is mapped to a method in my web part code. When I click the button the whole page reloads and the web part is rendered again. Is there a way to prevent this reloading of the page? Is there a way to call the function method in the background? Something similar to AJAX.
Thanks,
Jagannath
You can use Ajax, it just requires some sharepoint configuration. Here are a few posts to get you started:
http://weblogs.asp.net/jan/archive/2007/02/26/using-the-ajax-control-toolkit-in-sharepoint.aspx
http://sharepoint.microsoft.com/blogs/mike/Lists/Posts/Post.aspx?ID=3
Ajax or SilverLight are your only two options for Async operations without a page refresh.
Once you know the tricks needed to get SharePoint and ASP.NET AJAX to work together it's not that difficult.
Here are the steps required:
Ensure the ASP.NET AJAX Extensions are installed on all the front-end web servers (this is not required if you are using .NET 3.5 as the Extensions are included in the Framework)
Update the Web.config file for the SharePoint Application to support ASP.NET AJAX
Ensure any page that is going to use AJAX has a ScriptManager
Use an UpdatePanel or a client-side service call to get updated data and re-render the Web Part
This blog post has some resources from a talk I did on the subject at TechEd Barcelona 2008. These resources should give you the information you need to get started.
http://msmvps.com/blogs/windsor/archive/2008/11/13/teched-emea-resources-and-demos-integrating-asp-net-ajax-with-sharepoint-2007.aspx