What is the recommended replacement of ASP.Net server controls in the bright new world of ASP.Net MVC?
In my opinion, one of the best features of ASP.Net is the ability to write server controls (although, admittedly, the event model is horrendous to deal with). If these controls are self-populating, then they can be shared between different projects with the minimum of fuss - you simply reference the assembly where the server control lives, and drop it on to the aspx. The control does the rest. This fits very nicely in the World of Widgets and provides efficient code reuse. How is one meant to achieve the same thing in MVC?
I am most interested in self-populating controls that do not post back, as I appreciate that the postback model definitely does not fit with MVC. Can they still be encapsulated in a class that can be shared between a number of different MVC web projects? Or does this require a whole different mindset where controls shouldn't populate themselves, and one should use partial views? Is there a way of sharing partial views between projects?
Finally, can I use my old (non-postback) server controls, in an MVC projects?
You can mimic the behavior of non-post back controls with Html helper extension methods. Just like Html.TextBox(), etc, you can write your own and encapsulate them in their own project if you like.
If you've written controls that just output HTML, it shouldn't be that hard to convert them to Html helpers.
The closest Asp.Net MVC comes to server controls is partial requests. In a partial request an MVC action method is called, and its output is appended to the current view. Unfortunately, the official support for this (Html.RenderAction) is in the futures assembly at the moment.
If using the futures assembly is not possible for you, a blogger named Steve Sanderson has written an article on implementing similar functionality:
http://blog.codeville.net/2008/10/14/partial-requests-in-aspnet-mvc/
Related
I need to port the functionality of this one and only one AJAX control to MVC, but given the poor selection of MVC controls out there, I think I need to bring this legacy control into the MVC world...
I'd rather not taint my MVC project with ASP.NET controls, and welcome json/MVC alternatives you know of. (post them if you know of any)
Sample UI that I need in ASP.NET MVC
Back to porting
Although it's unfortunate that I am left to porting this control to MVC, it seems to be a widely accepted practice since Telerik has detailed instructions on how do this.
That makes me ask:
How common is it for a MVC website to use ASP.NET controls?
Again I'll mention I don't want to do this so I welcome MVC-specific alternatives. That being said, I'll proceed with trying to merge that control with my existing site. </End Disclaimer>
If you click on this hyperlink, and look at the source code at the bottom, can you tell me where I should put the following in MVC?
Code behind (My first instinct is to use a Controller but another SO question indicates I should create a create a ViewName.aspx.cs file)
How do I port the SQLDataSource to the new "Model" way of thinking. I know they are different in nature but I don't know how to present data to a ASP.NET control in a way that it will consume the information.
How do I handle the AJAX component? This control has an AJAX component using callbacks. Yes this is getting ugly, but it seems like I have to do this.
Apparently this model saves data in session or view-state. I have no idea if this even work in MVC. Guidance, an alternate control, or a life preserver is much appreciated.
I've already done research and have instructions from Telerik here and here that describes how to get started with placing a simple menu, but I need a little assistance with the more complex controls like this one.
Note: For all the commentary that has hit this question, please remember that I only want this one ASP.NET control functionality; I can't find a comparable control in MVC.
porting from asp.net webforms to MVC is a paradigm shift.
Directly porting does not work.
The Model is where you typically describe your data and do the data access
the View is for displaying the data
The controller plums the other two together
So SQLDataSource is your data access layer and would therefore go to your model
the problem with the thought pattern of SQLDataSource == Model then you get away from the point of decoupling your presentation from data access
You have to think of MVC development as a new build
I would pick a book or video series from your preferred source and learn starting with MVC3 (it has some differences that simplify build speed and reinforce the difference between webforms and mvc)
Hope this helps.
This article explains how to run web forms and mvc together
http://weblogs.asp.net/rajbk/archive/2010/05/11/running-asp-net-webforms-and-asp-net-mvc-side-by-side.aspx
This is by telerik and explains the limitiation of the grid and what is need to get it to run.
http://blogs.telerik.com/aspnetmvcteam/posts/08-11-06/asp_net_ajax_controls_in_asp_net_mvc.aspx
Add an IFrame in your MVC view that just shows the WebForms page (or just use that control on a single WebForms page).
There is nothing that says you can't have a site with both WebForms and MVC pages. You can route a single URL to a WebForm just for this control.
Why not just use the telerik MVC controls? They work quite well. Either get them via a NuGet package or visit this link http://www.telerik.com/products/aspnet-mvc.aspx
I would rather use ViewModel instead of code behind
You don't have to throw away SqlDataSource you can use result set and buld from it your model, problem may be column names in result set... tricky but can be done
Since there is no components in MVC except helpers youll need help of jQuery probably, it easy
$.ajax({
url : "/controller/action",
data: { /*json or serialized form */ },
successs: function(data){
//if you got response as html from /controller/action
$("#some_div").html(data);
}
}
Session is available in MVC but viewstate not, you can use HttpContenxt.Cache or TempData if you need something like viewstate. USe TempData to keep data between redirections, or httpcontext.cache to cache your data further more.
I can't find similar functionality in an MVC control
MVC doesn't really have a concept of controls in the same way that ASP.Net does - there are only really the plain old HTML controls (i.e. hidden input, text input, checkbox, radiobuttons, select box, text area, password and buttons).
When you need something more complicated than the plain HTML Controls you need to use some JavaScript to achieve this.
I'm not sure that you will be able to 'port' the control into MVC - you will most likely have to try and re-create it your self using an MVC controller and a partial view with a fair bit of a javascript to create the control.
Have a look at the JQuery UI Autosomplete plugin - you could probably use this to acheive something similar
Ive been doing a bit of research / reading into mvc recently and was just wondering what the main purpose is.
is it as some people say to seperate the logic from the html
or to create clean url's
i could be missing the point completely, but asp.net forms really seperates the logic from the html and if you just want clean url's why not use a mod_rewrite rule?
MVC is a software engineering concept which is used more widely than just in ASP.net.
In a nutshell it encourages strong separation of:
business logic (the Model) the code which does all the brute force work behind the scenes; dealing with the database, performing large calculations; and
user interface logic (the View) the code which presents information to your users in a pretty way.
The C is for Controller - the ligaments that bind the bones of the model and the muscles of the views and allow them to communicate with each other cleanly.
You are correct that 'normal' ASP.net uses code-behind files so that page markup is kept separate from the code that generates that markup (in contrast to languages like PHP where code is embedded directly amongst HTML), but MVC ASP.net encourages even more separation in the ways I described above.
Take a look at this tutorial for a more detailed discussion of the pattern. Also take a look at this SO question
The MVC pattern has nothing to do with rewriting URLs. ASP.net MVC might make this easier but that is not by any means it's main purpose.
Testability is a big benefit of using ASP.NET MVC. It is non-trivial to write unit tests for ASP.NET winforms. It is much easier to unit tests for Controllers.
If you are doing MVC correctly, your views should be very light, and a lot of your logic is implemented in the Controllers.
Let me compare the two for you:
Asp.net web forms
They matured the old ASP technology that was much more like PHP. Code and presentation were piled up in the same file. Asp.net web forms upgraded this model by providing a mechanism of separating the two. But they built on top of the good things that windows application developers had. The drag drop interface creation with control events just like they exist in a windows application. Event thought code was separate from HTML, they were not separated. You still reference a lot of view controls in your codebehind, hence they're still very much bound to eachother.
Therefore it was rather easy to start developing on Asp.net web forms. But non savvy developers soon got to a bottleneck they didn't know existed (like slow postbacks due to huge view state etc.). Technology used some tricks to make this work. But on a serious large scale application this became quite a problem. Developers had to mingle their code to make it work with Asp.net web forms framework. Their complex forms had complex codebehinds with hard maintainable code with complex state.
The good (as well the bad) thing were at that time rich server controls. Nowadays with web 2.0 they don't seem rich anymore since they don't actually support client side functionality as much as they should. So Microsoft decided to also cram in something else. Update panels. That made partial rendering (and Ajax) possible with almost a flick of a finger. But it came with a cost. Everyone that used (uses) it soon realised it's not a viable solution that a professional application could implement.
Asp.net MVC
Now we have a new technology that doesn't have much in common with Asp.net web forms except for its first part of the name. MVC framework actually does separate code from user interface (view). Controller actions (code that executes on any HTTP request) is kept small and doesn't do anything with visualisation (it doesn't bind data to certain controls etc.). Controller action barely prepares data for the view to either consume or not. It's up to the view. Controller code doesn't in any way shape or form reference any view controls or anything. They're actually separate in MVC.
Views on the other hand just display and provide data. They can be partially or fully rendered. They support Ajax functionality to the point that everyone would like to use. Actually everything is separated into basic little things. Divide et impera (divide and conquer) seems to be the save-line here.
There's not hidden functionality. No flirting with windows development. It pure request response framework. Developer has the ability to 100% control the visual aspect of their app. But for the cost of not having rich controls out of the box. Those may be provided by the community or some developers prefer to create per purpose controls that serve the process much better.
Which one is better then?
Both have their pros and cons. But if you decide to build a semi complex, modern and maintainable application I'd suggest you give MVC a go.
But if all you need to do is a 15 screens application (without any particular interface requirements) it would be much faster to create it using Asp.net web forms.
MVC is a design pattern. Its purpose is to separate business logic and presentation details.
ASP.Net MVC is a mechanism to create web applications using ASP.Net and the MVC pattern.
One of the features of ASP.NET MVC is the ability to use SEO friendly URLs to provide commands to the controller part.
You can do as you have stated but ASP.Net have provided you a mechanism to do this easier.
The way ASP.Net Webforms was designed is that it made it easy for you drag controls on to the web form and code the logic underneath. ASP.Net MVC is designed so you separate your concerns easier.
The URL part of the ASP.NET MVC framework is just a modern phenomena to produce search engine friendly urls. They've infact been around long before the Microsoft team decided to add them to the framework (which required IIS7 before it could be done with no IIS extension).
The greatest pros in my view come from being able to test more easily, and separating off the parts of your application more cleanly. The whole ActionResult architecture of the ASP.NET MVC framework makes it very easy to switch from AJAX to plain out POSTs.
Delphi 5 use to employ the MVC model for its ISAPI extensions, 10 years ago.
MVC is not just an ASP.net thing, it is a design pattern that was widely accepted before it was created within the .NET framework, the thing about MVC is the separation of data from presentation(user interaction) from the business layer. It was just a way for Microsoft to offer that type of design pattern under the .NET framework
Although guys before me already give enough answers to the queston of purpose of ASP.NET MVC there is one thing I would like to add.
The ASP.NET Web Forms tried to abstract html and web from web development. That approach lead to the lacks in performances and usage of rich javascript frameworks.It was possible to create web application without actual knowledge of the web.
And to answer to you initial question, the purpose of ASP.NET MVC, I'll quote Dino Esposito:
With ASP.NET MVC, you rediscover the good old taste of the Web—stateless behavior, full control over every single bit of HTML, total script and CSS freedom.
MVC existed long before people tried to use it in HTML pages. The main reason for MVC is to get a grip on the logic to drive your application. MVC allows you to clearly separate things that should be separate: The model, code which converts the model value for the display and the code which controls the model.
So this is not related to HTML or URLs in any way. It's just that MVC makes it really simple to have clean HTML and simple URLs.
Is there a new model or best-practise for creating complex controls in asp.net MVC?
Do you use code-behind or inline to mirror your view pages?
My model is this:
I tend to use Partial Views when there is a view element that I'll need to use more than once. Or if I need to display multiple complex object in a view.
I use RenderAction from the futures assembly when I need a "reusable widget" of sorts. It has it's own controller and is better at handling more complex logic than a Partial View.
Finally, I tend to write Html Helper methods for things I may use in other projects (like paging links, etc).
I would use a partial view for complex things. Check out this article
Controls in MVC don't generally have (any) code behind. You use PartialViews as ascx controls, you pass them a model and you display the contents of the model.
You can create custom controls in mvc and these compile to a dll which is moveable between projects etc and these are a little more complex but essentially they spit out html like the partial view does.
You can also create jQuery plugins that are pretty cool and again, they can spit out html based on a model.
So a typical mvc view may be comprised of several partial views each of which are dedicated to a model or hierarchy of models.
Partial views can also display partial views so you can send a complex model to a partial view which in turn renders other partial views each of which deal with a more atomic part of your model.
I've been writing a lot of my own HtmlHelper extension functions. The November meeting of http://www.c4mvc.net/ that was recorded today gives some great examples of control type code placed in HtmlHelper extension functions. The recording should be online soon.
You may also want to check out the Telerik Extensions for ASP.NET MVC. They're open source, so even if you don't use their controls, you can get some insight into controls in ASP.NET MVC by taking a look at how a commercial control vendor approached the problem.
Coming from a PHP turned webforms turned ASP.NET MVC background, I find myself relying a lot more on basic html/css/javascript.
I've never been a fan of controls, even with webforms because they always ended up being messy compared to js/html/css counterparts.
I've started using MVC reccently, and one thing that occurs to me is whether its possible for the concept of a Control to exist in MVC?
From what I see the framework allows the application to be nicely factored into Models, Views and Controllers, but I can't think of a nice way to take a "vertical slice" of that application and reuse it in another application.
What I mean by that is it strikes me that any UI components I build with MVC maybe not very amenable to reuse, in the same way you can reuse a Contol in ASP.NET WebForms. Ok, there are HTML Helpers but I am thinking of something more modular. Something more like the control model in WPF.
Does this dichotomy go to the heart of MVC vs WebForms, or can reusable UI components work in an MVC world?
You can still use ascx files and other features in ASP.NET Web Forms. The only missing piece in MVC is the postback model and view state oriented state management. There is no <form runat="server"> anymore and no automatically generated hidden fields. Except these, all other features can be used in ASP.NET MVC. You can still write controls that post data using a REST based mechanism and use them in your views.
So, yes, as long as your controls don't rely on a server side form for postback, you can use them exactly the same way you'd use in ASP.NET Web Forms.
I was looking for the same thing - for reusable widgets with their own data paths and found this on Steve Sanderson's Blog:
http://blog.codeville.net/2008/10/14/partial-requests-in-aspnet-mvc/
From the article:
"You’ve heard of partial views, so how about partial requests? Within any MVC request, you can set up a collection of internal partial requests, each of which can set up its own internal partial requests and so on. Each partial request renders a plain old action method in any of your plain regular controllers, and each can produce an independent widget."
This article respectfully offers a alternative to The MVC Contrib Group's Sub Controller strategy (http://www.mvccontrib.org/) which is also a solution for what you are looking for.
I guess its harder in MVC to completely encapsulate rendering and post back handling in a single control you just drop on a page. It some ways this is because ASP.NET Webforms is very abstracted from HTTP semantics and that abstraction is a framework where its possible to create reusable user controls.
ASP.NET MVC doesn't have the abstraction of webforms so you can have a control the posts to three different controllers. While it may feel like your losing easy to use controls when you move to ASP.NET MVC, I think you have a better framework for separating and reusing domain logic.
In ASP.NET MVC you have partial views which can be reused. Rob Conery has a good post on this: ASP.NET MVC: Using UserControls Usefully
I think the closest thing you'll get to an old school controls are partial views, these are effectively just shared markup that you can drop on any page. However they don't have their own controllers out of the box so the code to power the shared UI component (the partial view) would need to exist in the controller of every page that used it. There are ways to reduce the duplication of code but without implementing partial view controllers and binding I don't think there is a way around it completely.
Like many others on this site I am considering a move to ASP.NET MVC for future projects. Currently my sites are running the traditional ASP.NET 2.0 Web Forms, and it works OK for us, so my other option is just to stick with what I know and make the move to ASP.NET 3.5 with the integrated AJAX stuff.
I'm wondering about how user controls work in ASP.NET MVC. We have tons of .ASCX controls, and a few composite controls. When I work with web designers it is very easy to get them to use ASCX controls effectively, even without any programming knowledge, so that's a definite plus. But then of course the downsides are the page life cycle, which can be maddening, and the fact that ASCX controls are hard to share between different projects. Composite controls are share-able, but basically a black box to a designer.
What's the model in ASP.NET MVC? Is there a way to create controls that solves the problems we've dealt with using ASCX and composite controls? Allowing easy access for web designers without having to worry about code being broken is an important consideration.
To implement a user control you do the following call:
<% Html.RenderPartial("~/Views/Shared/MyControl.ascx", {data model object}) %>
You may also see the older syntax which as of PR5 is not valid anymore
<%= Html.RenderUserControl("~/Views/Shared/MyControl.ascx", {data model object}) %>
You will always have to worry about code breaking when moving from Web Forms to MVC, however the ASP.NET MVC team has done a great job to minimize the problems.
As Nick suggested, you will indeed be able to render your user controls, but obviously the page-cycle, pagestate and postback from traditional ASP Webforms won't work anymore, thus making your controls most likely useless.
I think you'll have to rewrite most of your complex controls to port your website to MVC, while simple controls which, for instance, provide only formatting and have no postback status, should simply work.
The code provided by Nick will simply work in this case.
And about sharing between more projects: I think controls will be more like "reusable HTML-rendering components" that can be shared across a website, rather than "reusable code components" with logic (like WebForms controls). Your web logic will/should be in the pages controllers and not in the HTML controls. Therefore sharing controls across more projects won't be so useful as in the WebForms case.
MVC has different page life cycle compare to your user control.
You may consider this to re-write.
The aspx is the view. You still need a re-write, the syntax is different.
JavaScript will work. But I hardly find the WebControls will work. Because MVC does not have viewstate and postback anymore.
For the code behind (aspx.cs) you need to convert that to be a Controller class.
Page_Load method will no longer works. You probable leave it to Index() method.
Model is simply the entity classes that your code behind consume.
Conclusion, it's a total rewrite. Cheers. Happy coding.
Yeah, you can do RenderPartial. That's a good start. But eventually these guys will need logic and other controller type stuff. Be on the lookout for a subcontroller implementation from the framework team. There should also be something in MvcContrib soon. Or roll your own.
Edit: I just posted about this here: http://mhinze.com/subcontrollers-in-aspnet-mvc/