Ajax请求与普通MVC

Question

I am pretty new to MVC, but my research has pointed out that I can either use the default way to send requests to my controller, via forms, or I can use jQuery and Ajax requests.

Is it common practise to use Ajax all the time, so that I can avoid page reloads when I don't want then, and allow for loading icons?

Should the two ways of sending data to the controller be mixed? Using forms is easier, I guess, as you would need to coffee all your model properties manually in Ajax, I think, but it looks like you Haddin more flexibility.

I'm wondering if this pattern (using predominantly Ajax requests) is a good idea.

Answer 1

I think mostly its a matter of preference but I think using AJAX with jQuery provides for a more flexible and responsive application. Also it doesn't have to be more work. To submit all of your model properties that you had in the form to the controller you would just need to do something like:

$.ajax({
   url: "SomeController/SomeMethod", 
   data: $('#FormName').serialize(),  //this will basically do what MVC would have done if you used forms and a submit button
});

And on the controller the model binder will bind all of your properties back up to the model.

So you would have:

public ActionResult SomeMethod(SomeModel someModel)
{
  // do work with your tightly bound model!
  return View();
}

But...if you just want to know the Pros of AJAX and some of the CONS that you will also encounter then here you are:

PRO:

In many cases, related pages on a website consist of much content that is common between them. Using traditional methods, that content would have to be reloaded on every request. However, using Ajax, a web application can request only the content that needs to be updated, thus drastically reducing bandwidth usage and load time.

The use of asynchronous requests allows the client's Web browser UI to be more interactive and to respond quickly to inputs, and sections of pages can also be reloaded individually. Users may perceive the application to be faster or more responsive, even if the application has not changed on the server side.

The use of Ajax can reduce connections to the server, since scripts and style sheets only have to be requested once.

State can be maintained throughout a Web site. JavaScript variables will persist because the main container page need not be reloaded.

CON:

Owing to their dynamic nature, Ajax interfaces are often harder to develop when compared to static pages.

Pages dynamically created using successive Ajax requests do not automatically register themselves with the browser's history engine, so clicking the browser's "back" button may not return the user to an earlier state of the Ajax-enabled page, but may instead return them to the last full page visited before it. Workarounds include the use of invisible IFrames to trigger changes in the browser's history and changing the anchor portion of the URL (following a #) when Ajax is run and monitoring it for changes.

Dynamic web page updates also make it difficult for a user to bookmark a particular state of the application. Solutions to this problem exist, many of which use the URL fragment identifier (the portion of a URL after the '#') to keep track of, and allow users to return to, the application in a given state.

Because most web crawlers do not execute JavaScript code, publicly indexable web applications should provide an alternative means of accessing the content that would normally be retrieved with Ajax, to allow search engines to index it.

Any user whose browser does not support JavaScript or XMLHttpRequest, or simply has this functionality disabled, will not be able to properly use pages which depend on Ajax. Similarly, devices such as mobile phones, PDAs, and screen readers may not have support for the required technologies. Screen readers that are able to use Ajax may still not be able to properly read the dynamically generated content. The only way to let the user carry out functionality is to fall back to non-JavaScript methods. This can be achieved by making sure links and forms can be resolved properly and do not rely solely on Ajax. In JavaScript, form submission could then be halted with "return false".

The same origin policy prevents some Ajax techniques from being used across domains, although the W3C has a draft of the XMLHttpRequest object that would enable this functionality.

Like other web technologies, Ajax has its own set of vulnerabilities that developers must address. Developers familiar with other web technologies may have to learn new testing and coding methods to write secure Ajax applications.

Ajax-powered interfaces may dramatically increase the number of user-generated requests to web servers and their back-ends (databases, or other). This can lead to longer response times and/or additional hardware needs.

what are the advantages and disadvantages of making ajax calls using jquery?

Answer 2

It is the way works a single page application (SPA). I would suggest to use a javascript data framework like AngularJS (MVW pattern), Backbone (MVC pattern), KnockoutJS (MVVM pattern).

You don't have (shouldn't) to duplicate your models in the javascript data layer. The thing you will loose is the MVC.net view templating thought.

You can mix both but you then get the both sides drawbacks.

Here an official microsoft SPA demo built with KnockoutJS :

http://www.asp.net/single-page-application/overview/introduction/knockoutjs-template

I am working on a SPA at the moment with all in AJAX (except Authentication), IMO it gives a new great dimension to UX.

Answer 3

It's very common practice and I think one of the reason why Microsoft introduced webapi, so you don't really use their mvc but all is dependent on your ajax call, or other js framework, like ember/angular js.

It takes more time to setup/code ajax way but it performs faster to what user see.