Architecture :: Design Patterns For Handling User Web Navigation And Flow?
Jan 20, 2011
Our site is expected to allow the user to do whatever they want from a number of different places. Except, that doing whatever they want really means firing off mini sequences of pages they must vist (or possibly abort from to go off to another task) before returning to their starting point. So, at any given time, the user has a list of pages they are allowed to go to, a list of pages they must go to in order to complete their task, and some end point they must eventually return to, all of which are constantly changing.
As an example, a user may choose to edit an order they placed, at which point they must step through a series of pages to edit the order. These pages to edit an order may be different based on the type of order they are editing, and they must return to whatever place they were at when they decided to start editing the order. They may also have certain options of other pages to visit during their order editing process.
I really need a good way to handle this for a large number of different scenarios, and allow it to be easily changed. Right now we are doing things like setting session variables when a user chooses an action and checking them within the page on button handlers to see what they are allowed to do or where they are allowed to go. I'd love to be able to abstract this out into something that can be easily examined in one place, or even data driven, and have some sort of navigation controller pointing them to the pages they can or must go.
I need to create a singleton that would hold lots of data for a spedesign patterns - Singleton behavior with multi-user requests in ASP.NETcific user. However, I am not unclear as to what the behavior of that singleton is in regard to multi-user app requests.
Here is the scenario:
On AppStart event I want to load common data for all users (from SQL) and store it as a collection somewhere within the ASP.NET storage mechanisms.
If I store that data in the cache, I would also have to create a static property in the Global.asax that would provide access to that the data from the cache.
This is not ideal because whenever an instance of any particular page, or generic handler, or what have you tries to query this data using Linq the property has to load the data from the cache... introducing latency. I need this data to be immediately available. (think of it as about 5K rows of data stored in collection of objects...)
I was thinking to use a singleton to get that data, and store it but I don't know how it would behave between requests (and postbacks), as well as application instances, in terms of its persistence.
On PostAuthenticate event I want to get user specific data from SQL in the form of a collection. If i store it as a singleton (in a similar manner as the common data) i am not clear as to:
How is the data persisted? What is the scope of that singleton (it should be for the duration of the user session). How can I ensure that the data is immediately available to whatever needs to consume it? What happens between post-backs to that singleton? If another user logs in would another instance of that singleton be created for that specific application instance?
I need to design a good exception handling. That can include logging and user friendly error page etc I read more articles and got some ideas. I am not using Enterprise Library now.
what are design patterns and UML diagrams with best examples. How we should use in real time scenarios. Recurring iam facing these type of questions in project round.
I'm trying to build a small, web application. But I want to use desing patterns in it. So I have a question: which desing patterns do you use and why in asp.net applications?
I'm trying to decide which of the two factory patterns I should use in my Asp.Net applications:
1 : All DAL providers derive from same abstract base class DepartmentsProvider, which defines public interface of the class ( all the necessary CRUD methods for which derived classes (providers ) provide a concrete implementation ). BLL layer instantiates correct provider by calling DepartmentsProvider.Instance:
public abstract class DepartmentsProvider { static private DepartmentsProvider _instance = null; /// <summary>[code]....
In first case we implement new provider by deriving from DepartmentsProvider class, while in second case new provider is implemented by deriving from DBProviderFactory. What are pros and cons of each implementation?
which one is better in "Session Facade Class" and "Singleton Object" design patterns in ASP.Net? Also, please state the scenarions where specific design pattern is advisable to use.
Does anybody knows good, short and slim tutorials (not here ), which describe actual/modern web-application architectures / patterns (especially for ASP.NET based (classic and MVC) applications (maybe also with embedded Silverlight components) ? How would you you design today an ASP.NET application which uses different datasources (databases, services,...) ? Background: I has been away a couple of years writing web applications, and I want to start now again. So at the moment I am a little bit unsure, how to take off and find the right starting point.
I've been reading recently about EF4, and how to build an architecture for asp.net web forms application using it.
I explored using POCOs (self tracking entities), with WCF, but found out that my application will be deployed on a single box (i.e. one tier), so I started reading about logical separation of layers, and came up with the following solution:
DAL layer that contains EDMX model and EF APIs, and also generated context object.Entities DLL that holds all generated POCO entities using ADO.NET POCO entity generator. (for persistence ignorance, and decoupling entities from DAL).Business layer that contains a façade for each related group of business functions, the façade will be aware of and using DAL layer. And in each function, it will initiate context and uses different entities to carry out specific job (i.e. function).UI layer that only calls the business layer façade classes. With no awareness of DAL, but it will be aware of entities (i.e. using entities DLL), as the business layer will return results basically as entity collections.
I want to know what you think about this architecture.
I also read about an architecture that uses repository and unit of work patterns, but what I understand that context object is already implementing a UOF pattern, and also object sets are implementing repository pattern (correct me if I'm wrong), so the only advantage of using additional abstraction over them is to make the business layer communicates to my classes, not EF classes, and this is good only if the DAL strategy might change (i.e. by using another tool other than EF, which is not my plan).
I read some article about unitOfwork and repository but i'm still confused about how they interact, and how to use them in the right way.
I'm using an addressbook project to practise on patterns (even if , likely, patterns are not usefull) without any ORM framework for persistence.
My domain objects are (at now) : AddressBook (acts as an application controller), Contact (contains information about each contact in the address book), ContactGroup (mantain collections of contact).
Should i have to use distinct repository object for contact ad contactgroup?
I thought to use a UnitOfWork for the operation about the adding/removing contact to group : the user can add existing contact to a group, create a new contact while adding it to the group or remove contact from group.
I am having troubles understanding the purposes of using Factory pattern, I understand Factory pattern uses Factory class that has methods to return concrete objects. But why don't I simply use new opertor to create concrete objects? Some articles suggest Factory methods could return objects of different concreate classes, I can do the same thing by using switch statement.
Also are there classes in .Net framework already implementing Factory pattern? I think that will give me a better ideas why it is useful.
i want to create a centralised business or Service authendication architecture in .net. for example, we have a clients like c1, c2, c3, c4, ... etc. everybody logins seperatly as well as grouply. ie, if client "C1" logins [with login authentication] he can access c2 , c3, c4 also without login authendication. So its like a google. if we enters gmail account, we can access orkut, picasa like that.. i need the cetralised architecture.
And, client "c1" seperately asks seperately how will be the authendication architecture.
so give me the single solution for both these two scenarios. how will be the architecture for these two and how is the Data Base (Login) Structure.
recently i've studied on ADO.NET's Entity Model Framework and say 'wow' as ORM is one of the fevourite pattern i practice..but suddenly i've come to an ambiguous situation when i'm going to start. i usually follow the following 3-tier architecture..
1. UI Layer 2. BLL - business logic layer 3. DAL - Data Access Layer a. DTO / DAO b. Gateway (contains the sql query/stored procedure and connection with DB)
now when i'm going to use the Entity Model Design,where the DBML/ .edmx File should be placed? Because many a times i'm using the DBML file as DTO because of the mapped objects.. in the same time, sometimes DBML ( .edmx file in .NET 4.0) contains CRUD methods and stored procedured method as well as methods with different selection operations,- which should be in Gateway. so where the .edmx file should be placed !?!! IN DTO namespace !? or in Gateway namespace!
moreover sometimes there is no need for the BLL which breaks the rules of inter-layer-communication (UI > BLL > DAL.Gateway)! what makes me confuse is, what should be the ideal n-tier architecture when i'll use the ADO.NET Entity Model Design Framework
I am a newbie to asp.net and work in a firm where the projects are quite small.
I was told by my manager that in a few weeks or so we would be getting a bigger project and I need to be well versed with Design Patterns and N tier arcihtecture.
I would really appreciate if someone could provide me some links and also drop me a few sentences on how this things are useful?
I am try to create architecture design for WCF service.
We have WCF service that we have to expose to third party so then can request with xml and get back xml response.
The wcf service should do the following:
- Accept the request call with xml
- Check xml against the schema
- Parse the xml
- Authenticate the incoming xml by username and password that will be in xml
- Send back the response
If anybody can let me know what kind of design I can use or is there any pattern available that I can take it and then extend it as per my requirement.
i created an intranet based website(information Portal)...i would like to know the pages each user visits and i want track there behavior...what tools should i include..
I am currently working on a document management system in ASP.NET 3.5 using the Telerik AJAX toolkit. It consists of masterpage with a title banner across the top and a RadTreeview down the left hand side for navigation through the site. The treeview uses a combination of static nodes and dynamic ones. The dynamic nodes are populated via a webservice. When a node is clicked the relevant page is navigated to, reloading the masterpage and displaying the content of the target page.
The problem comes from the fact the treeview's dynamic nodes are populated via a webservice and therefore as the user navigates through the tree to find a document the treeview behaves as you would expect. However, when you get to the bottom of a tree of dynamic nodes the navigation to the page of the navigateurl causes the relevant page to be loaded and then the treeview resets itself to a collapsed state. This means the user could be deep in a nest of documents but when they view one, the tree collapses and they have to start their navigation all over again. This limitation is not going to be acceptable from an ease of use perspective.
According to Telerik, this is the designed behaviour for performance reasons - the node only ever worries about populating the next set of nodes and therefore the treeviews state is not remembered in viewstate.
So, the meat of question is. Is the masterpage/async treeview navigation design pattern a valid one? Are there any other ways to have an ajax treeview on a masterpage, that remembers it's state when another page is navigated to? I have considered a siglepage/updatepanel/partial page rendering model but the opinions I've seen on the net infer that this is bad idea. It confuses users that expect back/forward browser behaviour to navigate through the site but in a single page world they would end up leaving the site.
I also thought that maybe using a single page container and an iframe may work but this seems to be moving away from the "standard" design pattern of using masterpages.
I will try to explain my doubt and keep the code out, maybe for a second post. The greatest problem i am facing here is the logic :P.
At this point i have two tables: Empregado (Worker) and Cargo (Post). One post have many workers and one worker has only one post. In the database i think i am fine, a simple relationship one - many.
I've mapped the tables into classes with the same fields. As well i've created collections using generic lists. Each collection has a method that acess the bank and recover the data.
My worker class agregates one instance of post. I mainly use this to show the data i need. Basicaly i do a select, join the tables and fill the properties of the worker and the post.
The doubt: Is this a good pattern? Up to this moment i am not worried with blinding light performance, but in how to act in an good OOP pattern.
Even though I'm trying to implement exception handling in a multi-tiered Windows application, catching and throwing exceptions should be the same for Windows and Web (sans global.asax and web.config custom errors).
I have a webform with a texbox that displays exceptions. So my webform invokes a method in BusinessTier class which then invokes a method in DataTier class. How can I throw my DataTier method exception so it reaches my webform?
how do you treat situations where there is the need of storing collections of object belonging to an object not persisted on db (not yet). For example , suppose we have a web application for submitting orders. The user click on 'Create new order" , then insert order's data , choose items from a catalog and add them to the order. Finally he "submit" the order. I can see two different way to persiste data :
a) create on db an empty order instance when user click on "create new order" , so that the orderitems collection could be directly associated (saved) with that instance in the db.
b) keep all data in memory and finally save order and orderitem.
The b option imply storing (in session?) the orderitems collection till submit. Are there, probably, other solutions. Which are best practices in these situation?
