Where Does JQuery/Client-Side Programming Fit Into MVP and DDD - asp.net

I'm working on an a pretty big project right now and am trying to implement an MVP architecture. I'm starting to run across a instances where I think JQuery or Javascript might be better suited than server-side code. I'm looking for feedback on how others are implementing client-side programming into their enterprise applications. How are you structuring the client-side code and how do you determine when to use it?

Things that can make user say "wow". For example - Populating search results while user has just typed 3-4 character of search term. Just go back in past and think about Yahoo or Hotmail which used to postback to server when you clicked on "Create Message". But when google came they just did on client side without going to server. I bet you would have said "wow" to that. At least I did.
Things that can reduce server load. For example - Adding extra data entry row in HTML table, instead of doing it through round trip, Increase/Decrease of quantity etc.
These are just some example to sight. Even to do these things properly you need to go to server but that will be behind the scene using ajax. Other than this you need to select few more jquery plugins that you will use in your project. To name some are jQuery UI, jQuery Validation, jQuery AnythingSlider etc. There are too many of them.
Http://ClearTrip.com is one site that I envy for their UX. Visit their site from mobile device and you will get further clues about their UX work. Besideds just coding you need to have a person in your team who can work on these UX aspects.

Regarding how this fits into DDD: I've just recently started my journey into DDD but one hears a lot about command/query separation in that circle. Certainly if you are doing something that hits your domain (like fetching for auto-completion or certainly if you allow partial page submission to accomplish a domain command) you have to decide how it gets there and how the domain is structured to handle it.
I think two decisions are most relevant.
First, bits entirely in the browser and even those specifically in your application layer are outside your domain and thus, though covered in the layered architecture part of the DDD discussion, do not land in the entity/value/event/service, etc. discussion. If, however, you are using AJAX to interact with your application layer and in turn need to access your domain, you need to consider again two things in my mind.
(a) Are you separating commands and queries simply using different methods on your domain? Fine if you have a relatively small demand for either queries or commands and this will not seem like "noise" in your domain API. Otherwise, you have a separate bounded context...another domain modeled just for queries that your UI needs to avoid clutter on your domain. Regardless, you are doing something like JS->AJAX handler in application layer->domain (including a domain service).
(b) Is this a command or a query? Once you have (a) figured out, this lets you know where the access will land...then use the presentation layer's use case to elaborate the domain concept and put it into your ubiquitous language.
Second, you have the DTO vs direct to domain decision. This can be a religious war gathering topic, but usually the answer is "depends." I think there are cases for using DTOs and cases for not (within the same architecture)...just search for all the discussions around the topic and apply the pattern only where it adds value; I won't try to cover details here.
Hope this provides some insight or at least conversation magnet to which others will add.

I guess this question is a little too subjective. Looks like I'm just going to grab a view books on advanced javascript and study up on the JQuery library.

Related

creating an ajax application

I have several pages of my web application done. They all use the same master page so they all all look very similar, except of course for the content. It's technically possible to put a larger update panel and have all the pages in one big update panel so that instead of jumping from page to page, the user always stays on the same page and the links trigger __doPostback call-backs to update with the appropriate panel.
What could be the problem(s) with building my site like this?
Well, "pages" provide what is known as the "Service Interface layer" between your business layer and the http aspect of the web application. That is all of the http, session and related aspects are "converted" into regular C# types (string, int, custom types etc.) and the page then calls methods in the business layer using regular C# calling conventions.
So if you have only one update panel in your whole application, what you're effectively saying is that one page (the code behind portion) will have to handle all of the translations between the http "ness" and the business layer. That'll just be a mess from a maintainable perspective and a debugging perspective.
If you're in a team that each of you will be potentially modifying the same code behind. This could be a problem for some source control systems but one or more of you could define the same method name with the same signature and different implementations. That's won't be easy to merge.
From a design perspective, there is no separation of concerns. If you have a menu or hyper link on a business application, it most likely means a difference concern. Not a good design at all.
From a performance perspective you'll be loading all of your systems functionality no matter what function your user is actually doing.
You could still have the user experience such that they have the one page experience and redirect the callback to handlers for the specific areas on concern. But I'd think real hard about the UI and the actual user experience you'll be providing. It's possible that you'll have a clutter of menus and other functionality when you combine everything into one page.
Unless the system you are building a really simple and has no potential to grow beyond what it currently is and provide your users with a one page experience is truly provide value and an improved user experience and wouldn't go down this route.
When you have a hammer, everything looks like a nail.
It really depends on what you are trying to do. Certainly, if each page is very resource-intensive, you may have faster load times if you split them up. I'm all for simplicity, though, and if you have a clean and fast way of keeping users on one page and using AJAX to process data, you should definitely consider it.
It would be impossible to list too many downsides to an AJAX solution, though, without more details about the size and scope of the Web application you are using.

Front-end first or back-end?

Hi I have to do a small CMS application in MS ASP.NET using WebForms.
I do everything on my own: front-end and back-end and Data Base schema.
Now that I want to develop the site, I wonder if I should start from front-end first, or back-end.
Considering this is a small project, could you guys give me a list of steps I do better following to help to determinate what is the best order for developing my application?
Thanks once again for your time.
You'll develop all tiers as you go most of the time
For some page you may first create database schema and fill it up with some dummy data and than work your way up.
For others you may start with a page itself and then write functionality that's needed to get it working. Especially when this page hasn't been envisioned enough. This is not bad nor good. It's just the way development tends to be.
Some considerations
Follow agile development
Write down some requirements in a form of user stories (and keep track of them), that don't give any info about page, data etc. Just something like As a user I would like to have primary navigation on my page. This kind of a story will permit later changes to code/pages without the story becoming invalid.
Don't haste into something fully functional at first. Don't over-engineer your code. Because you'll end up doing changes later = follow YAGNI. For instance don't fully design your DB at first. Do just as much as you need per story being developed. But do think of future things that you'll have to integrate into existing codebase.
Refactor existing code right away when you see something should be changed.
If you have someone to test your code, let them do it. Don't develop next stories before existing bugs have been fully resolved. You'll be grateful for this later.
If your code is semi-complex I suggest you write unit tests, so future code changes won't break existing functionality.
Most of all: learn as you go and change existing code while doing so. Since you're learning these technologies I suggest you stick to simplicity at first. You'll add more complex things when needed. Some of them won't get done at all. So in the end youl realise YIDNI (yep, I didn't need it).
I usually write out what my requirements are first, if I need to use a database, I create that first, always. After my database I start working on front end that connects and uses my already created database.
I worry about the front-end last, can you can always change that pretty easily
I would say that in many systems, the back-end is there to support what is needed for the front-end to work. If you don't know what the front-end needs, there is little chance of successfully designing the back-end. So I'd start off with putting at least a rough front-end in place first (if even just a paper prototype).
I tend to approach all of my projects with a back-to-front approach for one simple reason - testability. Writing solid tests against a back-end early will will make it easier to work on the other tiers progressively. It also, as "bonus" helps to keep business logic out of places it does not belong.
I find it easier to develop the logic and back-end first, so that I get that right, then apply the interface to it. This way you avoid writing functionality based on what you think you need from the front end.
It is important to get a good scope of what you want to do/tackle, and try to implement that in the back-end first. Then wrap it in a nice interface!

Logging a user session for playback

Running an MVC2 site against IIS7 and would like to capture more detail of how users traverse the site - ideally to the point of being able to replay even the duration between mouse clicks - feedback of where people pause and/or backtrack.
I could do this with flash but that's no longer an option. Now it's just IIS7 via asp.net f4. IIS7 _should be able to provide this via 3rd party extensions - especially for this sort of niche need. I'm willing to consider client-side .net components but this sure seems to be the responsibility of the server.
[opps...does this belong on serverfault?]
thx
justSteve. Here is a solution that we have used:
http://www.seevolution.com/
I don't think that it gives time between clicks, but it does give very detailed tracking considering it's price (I don't know if that's an issue). We have really liked it. Fantastic detail.
You could also roll your own solution. Using jQuery and the $(document).click() function, you can log when they click, and the points on the screen. Then every couple of minutes, serialize it and fire it off to the server. You can get extremely fine-grained detail that way. The nice thing with seevolution is that they've done all of the work for you already, but it probably isn't as detailed as you would like.
JMax
Maybe not the "in-house" solution you're after but we are about to implement SessionCam at my company, which seems like a pretty good match for what you're looking for. Not having actually finished implementing it yet, I can't vouch for it in terms of quality at this point - but the description of the product certainly matches.
You aren't going to be able to capture the level of detail you need using a solely server-side solution. There needs to be a degree of client-side work - whether it's in flash or javascript - to capture things such as where the mouse is hovering (for heatmaps etc).
I personally haven't used this product, but a friend of mine spoke highly of it.
Clicktale

Web Pages That Just Do Too Much Stuff [closed]

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Concerning pages that build a web application:
Lately, I have found myself creating web pages that are simpler than the ones I used to. Before, I would try to jam as much functionality into a single page as I could to prevent from having lots of pages.
I am starting to realize that this was just making things way more complex, convoluted, and confusing than it had to be. Why not have more pages? I think the reason that I was doing this was because I didn't want the user to have to browse to other pages; just to have all the functionality they needed on a single page.
Well, these good intentions turned into an overly confusing interface for the user and very unmanageable source code. I am a new developer and I am trying to be very reflective of what I am doing so that I can improve. If it makes a difference, I am developing in ASP.net (though these are probably considerations for any platform).
My questions are:
Am I overthinking these things?
Has anyone else found themselves doing this?
Where is the happy medium?
There is no expert who can give you a rule that works in all places at all times. I have been known in my industry for years for "easy" interfaces and we've won significant amounts of business for it (as well as 5 "Best in Class" awards). I have also had people within my company and outside of it tell me - for years - that they like my work but wish that I would "jazz it up" with more graphics and such. What always amazes me is how little connection people see between the two.
So...a few rules of thumb:
A page should do one main thing.
A page may well have multiple links related to the main thing
Menuing and link layout should be consistent across pages
Simpler is better than more complex
Pages should be visually appealing and inviting
Rule 4 is more important than rule 5.
For example, my product provides an interface that lets people define classes and events to be displayed in a calendar. I could have one page that lets you Review, Add, Update, Delete and Edit the classes. Indeed, in some simpler areas, I've used the gridview to let people manage everything in a grid. However, classes have too much information to do this and still follow the rules above.
So,
The main idea is: "Here is a list of classes for this location"
The links are "Add New" shown above and to the right of the grid, Change and Delete are links within each row. This is consistent across the app.
Menuing for the system as a whole is always across the right/top. Nothing else appears on the class/event page except for standard elements common to all pages (a logo, a header, a footer).
The grid is nicely styled but there are no spurious graphics (4,5,6)
A few last things about UIs and graphic design.
First, develop your own vision and be consistent across pages and apps.
Second, do not be afraid of simplicity.
Next, when soliciting advice from others keep in mind that you do not want their advice - you want their impressions: you want to understand the way they perceive the interface. Advice is sometimes good but, more often than not, actually harmful. In my experience, everyone thinks that they are a UI expert.
When you do your hallway (or formal) useability testing you should discount almost all advice to the effect that "you should make that stand out more." As you'll see, it will quickly become "and that," "and that," "and the other." If you follow this advice, you'll end up with a mess due to Brittingham's first rule of design: If everything is important than nothing is. (There you go: when explaining why you can't make someone stand out more, just tell them that "it violates Brittingham's first rule of design!")
Hope this helps!
You hit the nail on the head. Use the KISS principle. (Keep It Simple Stupid)
I've done this in the past as well and not only does it make for a hideous UI, but confusing as to what operations you can do on the page due to having too much functionality. I've often found in testing that I did not have enough checks to see if the user could perform a certain operation based on the state of the data.
It's easy enough in ASP.Net to write several pages that do simple tasks and then link them together with Response.Redirect or Server.Transfer. Now all I try to achieve on any given page is what the design specs say. So if my page is just a search page, that's all I give. If the user wants to see the details of an item that was returned in the search, then I send them to an itemDetails.aspx page.
You've broken a wall that most software developers have, the one that was blocking your view on usability before. A lot of developers don't really think about it and try to make it easier for them by stuffing functionality in one window, web page or whatever.
The thing is once you start designing software from the user's point of view, i.e. making it easier, several things start to become clear. One is the issue of code maintenance, that code is easily more managable to work on if you don't stuff everything in one giant class or whatever travesty you've been doing. The other is usability itself, that you start to think how the user is actually using your application through the graphical interface. Third is avoiding requirements or scope creep where you stop developing functionality that the user doesn't need.
We as users want simplicity partly because we don't want to spend most of our time muddling through a bad UI when we can get our work done faster with a simple and slick UI. That makes it for us software developers the right thing to do, to think through your design on all levels... that and specs always lie.
Definitely agree: most attempts at writing pages/forms that do too much have resulted in
bugs and rewrites. Problems occur with keeping all parts valid/synchronized,
excess managing of users' expectations ("I've entered a bill number here and clicked "find person" there but it gives an error message. Why?") when the two are logically separate. These questions cannot arise if only the valid options are visible,
Formatting/layout issues: In ASP.NET pages, trying to layout independent User Controls turns out to be a nightmare ("But we really want all the buttons vertically aligned!" in separate user controls. Good luck with that.)
I'd consider webpages with more than one functionality only if the target audience consists of domain experts, i.e. people that need lots of functionality on one page for better productivity (think data-entry or financial software with lots of variables).
Even then, most of the time, it's possible separate pages into single units.
No
Yes - me
I found the happy medium was to use Masterpages, and using it in a way that was familiar to IFrames. That I could have a lots of functionality combined well together. There is a more interesting way of doing this with WPF/Silverlight called Prism
The amount of functionality on a page is usually not determined by you but by your customer. If the customer demands a single page to update some VeryComplexObject, you're likely to end up with an aspx page that has a significant number of lines. Main reason is that you simply have a lot of event handlers for all actions on the page.
Whether that page is complex is entirely up to you. You should always attempt to make your code-behind file as simple and clean as possible. Some suggestions in that direction:
Move all business code to another application layer.
Use ObjectDataSource for providing data to data-bound controls such as ListView, GridView, Repeater, ... Delegating loading of data to a dedicated object prevents a lot of overhead in your aspx.cs file.
Another suggestion is to use user controls to implement portions of your page. You would usually only do this when you can reuse the user control, but it can also be of great help reducing page complexity (both of your code-behind file as well as your aspx).
Sometimes I think we are all guilty of forgetting just who it is that we develop our applications for. It isn't always easy as a developer to be able to take a step back and have a look at your application as a user might do so. This is why big companies employee hundreds of people to do this for them and they don't always get it right.
Usability is a massive subject but it is defiantly something that all developers need to keep in mind. It has taken me a long time to learn this but when tackling any development task I always try to think about how my users are going to interact with what I am writing. This will make a difference to all levels of your development.
I would suggest reading Don't Make Me Think by Steve Krug. This book won't take you an age to read and it puts across some fantastic ideas that can help you to develop applications that are much easier to use and understand.
I always find that once I have thought about the user experience the decisions about what my web pages are going to do and how they are going to interact are much easier to make.
Maybe you should ask the people who are using your site. Or better yet, just watch people use your site. I think that would tell you if your site is designed well, or if you need to change it.

How to choose whether a web page should be a web user control?

A few guys on our team are of the opinion that every web page in the application should be a web user control. So you'll have all of your html + event handling in the Customer.ascx, for example, and there will be a corresponding Customer.aspx page that contains Customer.ascx control.
These are their arguments:
This practice promotes versatility, portability, and re-usability.
Even if the page is not re-used right now, it might be in a future.
Customer page might need to move to a different location or renamed sometimes in a future and moving user controls is easier.
This is a recommendation by MS for new development.
Is this really a recommendation for new development? Are there any drawbacks to this strategy? I agree that it's nice to have a user control on hand if the need arises, but it seems to be an overkill to do this to the entire application "just in case we need it later".
1, 2 & 3: Doing anything because "you might need it later" is a horrible strategy.
http://c2.com/xp/YouArentGonnaNeedIt.html
4: I have never read this and seriously doubt MS has ever said anything like this. Maybe some random article by one single person who has an MS tag or was an MVP or something, and a gullible junior dev took it as Gospel Truth.
Seriously complicates client-side script as the NamingContainer jiggery will prepend _ctl0 etc to everything sometimes.
I don't think MS ever recommended it. Request links to MSDN documentation.
Typically by the time your are done implementing something, and it is sufficiently complicated, you'll find a lot of "gotchas" when ever you try to "reuse" it. A good example is relative links in the user control that no longer work outside of their path.
Users don't need the ability to add/edit/delete Customers on every page. Indeed, you start to get into caching issues if you have these types of controls on every page. For example if on an Invoice page, you add a Customer, will the Invoice control be updated with the new Customer? All sorts of inter-control operability issues can manifest. These issues are hard to argue for, because of course, everyone's user control will be perfect, so this will never happen. ha ha right.
See if they can come up with an example where moving/renaming a user control actually saved time, instead of making it more complicated. Draw up an actual example and show the pros/cons of each.
Personally I'm not a fan, I think it adds a layer of complexity to the application that is not strictly necessary at the early stages. If you need to reuse a component that you had not previously thought would be reused, refactoring it into a user control at that point should not be very difficult.
I came across an application in .NET 1.1 that was written like that once. Someone must have heard that same misguided "best practice" and taken it for the absolute truth.
I agree that it adds a level of complexity that's mostly not needed. I usually find usercontrols more useful for something like portions of a page that are repeated on several pages. If you think you'd reuse the entire page... why not just use the original page?
I also don't understand the moving/renaming argument. It's not that difficult to rename/move a page. If you do what your colleagues are suggesting, you'd end up with a customers.aspx page that contains nothing but an orders.ascx file? I see more potential confusion/errors with that approach than by just renaming/moving a file.

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