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  • What types of objects should the ViewModel reference in the MVVM pattern?

    - by Blanthor
    I've seen quite a few examples of MVVM. I can see that the View should reference the ViewModel. I've seen recently an example of a ViewModel referencing a View, which seems wrong to me, as it would result in tighter coupling. Given that ViewModel is often described as an intermediary between the View and the Model, is there more to the ViewModel than a facade to domain objects? I hope I used the term "facade" correctly here.

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  • New or not so well-known paradigms, syntax features and behaviours of programming languages?

    - by George B
    I've designed some educational programming languages and interpreters for them, but my problem always was that they ended up "normal" and "boring", mostly similar to some kind of existing language (ASM and BASIC). I find it really hard to come up with new ideas for syntax features, "neat things" and new or very modified programming paradigms for it. I always thought that it was hard to come up with good new things not fun/useless new things for this case. I wondered if you could help me out with your creativity: What features in terms of language syntax and built-in functions as well as maybe even new paradigms can I work into my language to keep it useless but more fun, enjoyable, interesting and/or different to program in?

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  • How to evade writing a lot of repetitive code when mapping?

    - by JPCF
    I have a data access layer (DAL) using Entity Framework, and I want to use Automapper to communicate with upper layers. I will have to map data transfer objects (DTOs) to entities as the first operation on every method, process my inputs, then proceed to map from entities to DTOs. What would you do to skip writing this code? As an example, see this: //This is a common method in my DAL public CarDTO getCarByOwnerAndCreditStatus(OwnerDTO ownerDto, CreditDto creditDto) { //I want to automatize this code on all methods similar to this Mapper.CreateMap<OwnerDTO,Owner>(); Mapper.CreateMap<CreditDTO,Credit>(); Owner owner = Mapper.map(ownerDto); Owner credit = Mapper.map(creditDto) //... Some code processing the mapped DTOs //I want to automatize this code on all methods similar to this Mapper.CreateMap<Car,CarDTO>(); Car car = Mapper.map(ownedCar); return car; }

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  • Where should my "filtering" logic reside with Linq-2-SQL and ASP.NET-MVC in View or Controller?

    - by Nate Bross
    I have a main Table, with several "child" tables. TableA and TableAChild1 and TableAChild2. I have a view which shows the information in TableA, and then has two columns of all items in TableAChild1 and TableAChild2 respectivly, they are rendered with Partial views. Both child tables have a bit field for VisibleToAll, and depending on user role, I'd like to either display all related rows, or related rows where VisibleToAll = true. This code, feels like it should be in the controller, but I'm not sure how it would look, because as it stands, the controller (limmited version) looks like this: return View("TableADetailView", repos.GetTableA(id)); Would something like this be even work, and would it be bad what if my DataContext gets submitted, would that delete all the rows that have VisibleToAll == false? var tblA = repos.GetTableA(id); tblA.TableAChild1 = tblA.TableAChild1.Where(tmp => tmp.VisibleToAll == true); tblA.TableAChild2 = tblA.TableAChild2.Where(tmp => tmp.VisibleToAll == true); return View("TableADetailView", tblA); It would also be simple to add that logic to the RendarPartial call from the main view: <% Html.RenderPartial("TableAChild1", Model.TableAChild1.Where(tmp => tmp.VisibleToAll == true); %>

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  • How to find the entity with the greatest primary key?

    - by simpatico
    I've an entity LearningUnit that has an int primary key. Actually, it has nothing more. Entity Concept has the following relationship with it: @ManyToOne @Size(min=1,max=7) private LearningUnit learningUnit; In a constructor of Concept I need to retrieve the LearningUnit with the greatest primary key. If no LearningUnit exists yet I instantiate one. I then set this.learningUnit to the retrieved/instantied. Finally, I call the empty constructor of Concept in a try-catch block, to have the entitymanager do the cardinality check. If an exception is thrown (I expect one in the case that already another 7 Concepts are referring to the same LearningUnit. In that case, I case instantiate a new LearningUnit with a new greater primary key. Please, also point out, if any, clear pitfalls in my outlined algorithm above.

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  • Why Do Programmers Get So Invested in their Favorite Technologies?

    - by Pierreten
    I've noticed this culture surrounding Ruby where developers truly believe that they are somehow more gifted than developers of other languages, regardless of experience and talent (even when that isn't the case, I've met some extremely junior Ruby developers come up with some pretty basic constructs, and pass them off as some sort of revolutionary idea). The derision of strongly typed languages seems to be a common theme as well; regardless of its merits. Is there something particular to the Ruby syntax in general that is to account for this? Is there a sociological component to it?

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  • What is MVC and what are the advantages of it?

    - by Teifion
    I found What are mvp and mvc and what is the difference but it didn't really answer this question. I've recently started using MVC because it's part of the framework that myself and my work-partner are going to use. We chose it because it looked easy and separated process from display, are there advantages besides this that we don't know about and could be missing out on? Pros Display and Processing are seperated Cons None so far

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  • How would I implement separate databases for reading and writing operations?

    - by Matt
    I am interested in implementing an architecture that has two databases one for read operations and the other for writes. I have never implemented something like this and have always built single database, highly normalised systems so I am not quite sure where to begin. I have a few parts to this question. 1. What would be a good resource to find out more about this achitecture? 2. Is it just a question of replicating between two identical schemas, or would your schemas differ depending on the operations, would normalisation vary too? 3. How do you insure that data written to one database is immediately available for reading from the second? Any further help, tips, resources would be appreciated. Thanks.

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  • Approaching Java from a Ruby perspective

    - by Travis
    There are plenty of resources available to a Java developer for getting a jump-start into Ruby/Rails development. The reverse doesn't appear to be true. What resources would you suggest for getting up-to-date on the current state of java technologies? How about learning how to approach DRY (don't repeat yourself) without the use of metaprogramming? Or how to approach various scenarios where a ruby developer is used to passing in a function (proc/lambda/block) as an argument (callbacks, etc)?

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  • Magento - How can I move the Navigation Block to be in the right column?

    - by Hank
    I've been editing Magento's default CSS to change the look and have come to a point where I want to move around some content blocks. I've killed off the left column through CSS .col-left { display: none; } And then increased the width of the main content part to create a 'two column layout'. What I want to do now is move the navigation for the categories into the right column. I just have no idea how... How do I move content blocks around in Magento? :/

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  • What's the simplest way to make a scrollable list of controls with labels?

    - by Jon Cage
    Using C++/CLI and Windows Forms, I'm trying to make a simple scrollable list of labelled text controls as a way of displaying some data fields. I'm having trouble making a TableLayoutPanel scrollable - every combination of properties I've tried seems to result in some really peculiar side effects. So I have two questions: Is this the best way to do it. If it is a reasonable approach, what magic combination of settings should I apply to the table layout panel to make it play ball?

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  • Fastest way to do a weighted tag search in SQL Server

    - by Hasan Khan
    My table is as follows ObjectID bigint Tag nvarchar(50) Weight float Type tinyint I want to get search for all objects that has tags 'big' or 'large' I want the objectid in order of sum of weights (so objects having both the tags will be on top) select objectid, row_number() over (order by sum(weight) desc) as rowid from tags where tag in ('big', 'large') and type=0 group by objectid the reason for row_number() is that i want paging over results. The query in its current form is very slow, takes a minute to execute over 16 million tags. What should I do to make it faster? I have a non clustered index (objectid, tag, type) Any suggestions?

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  • How do you unit test new code that uses a bunch of classes that cannot be instantiated in a test har

    - by trendl
    I'm writing a messaging layer that should handle communication with a third party API. The API has a bunch of classes that cannot be easily (if at all) instantiated in a test harness. I decided to wrap each class that I need in my unit tests with an adapter/wrapper and expose the members I need through this adapter class. Often I need to expose the wrapped type as well which I do by exposing it as an object. I have also provided an interface for for each or the adapter classes to be able to use them with a mocking framework. This way I can substitute the classes in test for whatever I need. The downside is that I have a bunch of adapter classes that so far server no other reason but testing. For me this is a good reason by itself but others may find this not enough. Possibly, when I write an implementation for another third party vendor's API, I may be able to reuse much of my code and only provide the adapters specific to the vendor's API. However, this is a bit of a long shot and I'm not actually sure it will work. What do you think? Is this approach viable or am I writing unnecessary code that serves no real purpose? Let me say that I do want to write unit tests for my messaging layer and I do now know how to do it otherwise.

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  • General question: Filesystem or database?

    - by poeschlorn
    Hey guys, i want to create a small document management system. there are several users who store their files. each file which is uploaded contains an info which user uploaded it and the document content itself. In a view there are displayed all files of ONE specific user, ordered by date. What would be better: 1) giving the documents a name or metadata(XML) which contain the date and user (and iterate through them to get the metadata) or 2) giving the files a random/unique name and store metadata in a DB? something like this: date | user | filename What would you say and why? The used programming language is java and the DB is MySQL.

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  • Would this constructor be acceptable practice?

    - by Robb
    Let's assume I have a c++ class that have properly implemented a copy constructor and an overloaded = operator. By properly implemented I mean they are working and perform a deep copy: Class1::Class1(const Class1 &class1) { // Perform copy } Class1& Class1::operator=(const Class1 *class1) { // perform copy return *this; } Now lets say I have this constructor as well: Class1::Class1(Class1 *class1) { *this = *class1; } My question is would the above constructor be acceptable practice? This is code that i've inherited and maintaining.

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  • mysql circular dependency in foreign key constraints

    - by Flavius
    Given the schema: What I need is having every user_identities.belongs_to reference an users.id. At the same time, every users has a primary_identity as shown in the picture. However when I try to add this reference with ON DELETE NO ACTION ON UPDATE NO ACTION, MySQL says #1452 - Cannot add or update a child row: a foreign key constraint fails (yap.#sql-a3b_1bf, CONSTRAINT #sql-a3b_1bf_ibfk_1 FOREIGN KEY (belongs_to) REFERENCES users (id) ON DELETE NO ACTION ON UPDATE NO ACTION) I suspect this is due to the circular dependency, but how could I solve it (and maintain referential integrity)?

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  • Singleton & Multithreading in Java

    - by vivek jagtap
    What is the preferred way to work with Singleton class in multithreaded environment? Suppose if I have 3 thread, and all they try to access getInstance() method of singleton class at the same time - What would happen if no synchronization is maintained? Is it good practice to use synchronized getInstance() method or use synchronized block inside getInstance(). Please advise if there is any other way out.

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  • What is a good architecture for a Lift-JPA application?

    - by egervari
    I was wondering what is the best practice for a JPA model in Lift? I noticed that in the jpa demo application, there is just a Model object that is like a super object that does everything. I don't think this can be the most scalable approach, no? Is it is wise to still do the DAO pattern in Lift? For example, there's some code that looks a tad bloated and could be simplified across all model objects: Model.remove(Model.getReference(classOf[Author], someId)) Could be: AuthorDao.remove(someId) I'd appreciate any tips for setting up something that will work with the way Lift wants to work and is also easy to organize and maintain. Preferably from someone who has actually used JPA on a medium to large Lift site rather than just postulating what Spring does (we know how to do that) ;) The first phase of development will be around 30-40 tables, and will eventually get to over 100... we need a scalable, neat approach.

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  • Should I Split Tables Relevant to X Module Into Different DB? Mysql

    - by Michael Robinson
    I've inherited a rather large and somewhat messy codebase, and have been tasked with making it faster, less noodly and generally better. Currently we use one big database to hold all data for all aspects of the site. As we need to plan for significant growth in the future, I'm considering splitting tables relevant to specific sections of the site into different databases, so if/when one gets too large for one server I can more easily migrate some user data to different mysql servers while retaining overall integrity. I would still need to use joins on some tables across the new databases. Is this a normal thing to do? Would I incur a performance hit because of this?

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  • How to represent a Many-To-Many relationship in XML or other simple file format?

    - by CSharperWithJava
    I have a list management appliaction that stores its data in a many-to-many relationship database. I.E. A note can be in any number of lists, and a list can have any number of notes. I also can export this data to and XML file and import it in another instance of my app for sharing lists between users. However, this is based on a legacy system where the list to note relationship was one-to-many (ideal for XML). Now a note that is in multiple lists is esentially split into two identical rows in the DB and all relation between them is lost. Question: How can I represent this many-to-many relationship in a simple, standard file format? (Preferably XML to maintain backwards compatibility)

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  • Table with unequal rows in XUL layout

    - by Michael
    Trying to get something similar for Firefox extension using XUL. The most difficult part is the grid with unequal number of rows. I tried <grid> but it didn't work well. Also don't want to use HTML inside of XUL. Any ideas how to build such table?

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  • Seeking free ODBC database optimization tool for non-experts

    - by mawg
    I'm a database n00b and am reading as many books as I can. I have been given responsibility for an ODBC tool where the databases were designed by a hardware engineer with some VB experience - which made him a s/w guru in the small firm at that time. Things are running slowly and I suspect that the db could have been designed better. I hope to learn enough to use Explain/Describe, etc maybe add some indices, but, in the meantime, is there any free for commercial use tool which can examine an ODBC database and suggest improvements. I'm just talking about db schema here, but maybe I should also be looking at optimizing Selects with Joins? Is there a tool for that? ODBC compliant.

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  • ASP.NET MVC Filters: How to set Viewdata for Dropdown based on action parameter

    - by CRice
    Hi, Im loading an entity 'Member' from its id in route data. [ListItemsForMembershipType(true)] public ActionResult Edit(Member someMember) {...} The attribute on the action loads the membership type list items for a dropdown box and sticks it in viewdata. This is fine for add forms, and search forms (it gets all active items) but I need the attribute to execute BASED ON THE VALUE someMember.MembershipTypeId, because its current value must always be present when loading the item (i.e. all active items, plus the one from the loaded record). So the question is, what is the standard pattern for this? How can my attribute accept the value or should I be loading the viewdata for the drop down in a controller supertype or during model binding or something else? It is in an attribute now because the code to set the viewdata would otherwise be duplicated in each usage in each action.

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