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• UML Modelling in C++Builder 2010 Professional

  - by Gordon Brandly

  I'd like to do some basic class diagram UML models in the Pro version of C++Builder 2010. Embarcadero has a C++Builder Features Matrix document, one line of which says "UML Code Visualization – at any time, get a UML model view of your source code" and has a check in the "Professional" column of that table -- I assume this means it should be available to me. Yet, when I open an existing project and do a View | Model View, there's nothing in the Model View window. The only diagram I can find is on the Graph tab of the C++ Class Explorer. I wouldn't call that a UML diagram myself -- is that what Embarcadero is referring to? Embarcadero's table shows that many UML diagrams are not available in Pro, but it looks to me like Class Diagrams should be available. Other lines in that same table indicate that both "Full two-way class diagrams with synchronization between code and diagrams" and "Diagram hyper-linking and annotations" are also supposed to be available in Pro. The Class Explorer graph is one-way only as far as I can tell, so I hope they're referring to something else I haven't been able to find so far. Thanks for any insight into this.

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• Handling data update/freshness issue in web-app in general (or GWT specifically)

  - by edwin.nathaniel

  In general, how do you guys handle user update/data freshness interaction with the user (UI issue) in web-apps? For example: Multi-users web-app (like project management) Login to a "virtual" space People can update project names, etc How to handle a situation such that: user-A and user-B load a project with title "Project StackOverflow" user-B updates the title to "Project StackExchange" user-A updates the title after user-B update operation to "Project Basecamp" The question I'm asking is from the user perspective (UI) and not about transactional operation. What do most people do in this situation? What would you do after user-B updates the title in user-A screen/view? What happened when user-A tries to update the title after user-B finished his/her update operation? do you inform user-A that the title has changed and he/she has to reload the page? do you go ahead and change the title and let user-B has old data? Do you do some sort of application-level "locking" mechanism? (if someone is updating, nobody else can?) Or fix the application workflow? (who has the access to be able to change things, etc). What would be the simplest solution, but at the same time not annoy the user with more dialog/warning messages. I've encountered this particular problem frequently in a GWT app specifically where domain models are being passed around and refreshing the whole app/client-side isn't the optimal solution in my mind (since it means the whole "loading"/initialization phase must be executed again in this specific environment). Maybe the answer is to stay away from GWT? :) Love to hear options, solutions, and advises from you guys. Thanks

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• How much does Website Development cost nowadays?

  - by Andreas Grech

  I am thinking of setting up my own freelance business but coming from a workplace that offers a particular service to huge clients, I do not know what are the current charges for websites are nowadays. I know that as technology just keeps changing and changing (most of the time, for the better...), the amount you charge for a single website is constantly differing. Like for example, I don't think static websites (with just static html pages) are that expensive today, no? (as i said, I might be mistaken since I haven't really touched on this freelance industry yet) So, freelance web-developers out there, can you give me estimates on how much you charge for your clients? Some examples of websites that I want to know an approx charge: ~10 static html pages ~10 dhtml pages (with maybe a flasy menu on the top/side) Database driven websites with a standard CMS (be it the one you developed, or an existing one) Database driven but with a custom-built cms for the particular client Using an existing template for a design Starting the design from scratch etc... I know that the normally clients don't really care about the technologies used to construct their websites, but do you charge differently according to which technology you use to build the website with?; as in, is the technology a factor when setting the price? ...being ASP.Net, PHP, Ruby On Rails etc... Also, how do you go on about charging your clients for your services? What are the major factors that you consider when setting a price tag for a website to a client ? And better yet, how do you even find prospective clients? <= [or should I leave this question for a different post?] Btw, in your post, also mention some numbers (in cash values, be it in USD, GBP, EUR or anything) because I want to be able to take calculate some averages from this post when some answers stack up

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• Problem Render backbone collection using Mustache template

  - by RameshVel

  I am quite new to backbone js and Mustache. I am trying to load the backbone collection (Object array) on page load from rails json object to save the extra call . I am having troubles rendering the backbone collection using mustache template. My model & collection are var Item = Backbone.Model.extend({ }); App.Collections.Items= Backbone.Collection.extend({ model: Item, url: '/items' }); and view App.Views.Index = Backbone.View.extend({ el : '#itemList', initialize: function() { this.render(); }, render: function() { $(this.el).html(Mustache.to_html(JST.item_template(),this.collection )); //var test = {name:"test",price:100}; //$(this.el).html(Mustache.to_html(JST.item_template(),test )); } }); In the above view render, i can able to render the single model (commented test obeject), but not the collections. I am totally struck here, i have tried with both underscore templating & mustache but no luck. And this is the Template <li> <div> <div style="float: left; width: 70px"> <a href="#"> <img class="thumbnail" src="http://placehold.it/60x60" alt=""> </a> </div> <div style="float: right; width: 292px"> <h4> {{name}} <span class="price">Rs {{price}}</span></h4> </div> </div> </li> and my object array kind of looks like this

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• Are document-oriented databases any more suitable than relational ones for persisting objects?

  - by Owen Fraser-Green

  In terms of database usage, the last decade was the age of the ORM with hundreds competing to persist our object graphs in plain old-fashioned RMDBS. Now we seem to be witnessing the coming of age of document-oriented databases. These databases are highly optimized for schema-free documents but are also very attractive for their ability to scale out and query a cluster in parallel. Document-oriented databases also hold a couple of advantages over RDBMS's for persisting data models in object-oriented designs. As the tables are schema-free, one can store objects belonging to different classes in an inheritance hierarchy side-by-side. Also, as the domain model changes, so long as the code can cope with getting back objects from an old version of the domain classes, one can avoid having to migrate the whole database at every change. On the other hand, the performance benefits of document-oriented databases mainly appear to come about when storing deeper documents. In object-oriented terms, classes which are composed of other classes, for example, a blog post and its comments. In most of the examples of this I can come up with though, such as the blog one, the gain in read access would appear to be offset by the penalty in having to write the whole blog post "document" every time a new comment is added. It looks to me as though document-oriented databases can bring significant benefits to object-oriented systems if one takes extreme care to organize the objects in deep graphs optimized for the way the data will be read and written but this means knowing the use cases up front. In the real world, we often don't know until we actually have a live implementation we can profile. So is the case of relational vs. document-oriented databases one of swings and roundabouts? I'm interested in people's opinions and advice, in particular if anyone has built any significant applications on a document-oriented database.

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• How did this happen?? Git error? Some other fluke?

  - by marfarma

  Every file in this Rails project is duplicated with a -e and again with a -e-e tacked onto the end of it, like the following. It's that way in my GitHub repository too. But I can't figure out how it happened. Any clue? Google searching comes up empty. -rw-r--r--@ 1 usrname staff 959 Jan 7 02:13 Gemfile -rw-r--r-- 1 usrname staff 958 Jan 5 01:10 Gemfile-e -rw-r--r-- 1 usrname staff 958 Jan 5 01:09 Gemfile-e-e -rw-r--r-- 1 usrname staff 6650 Jan 7 02:13 Gemfile.lock -rw-r--r-- 1 usrname staff 6650 Jan 5 01:10 Gemfile.lock-e -rw-r--r-- 1 usrname staff 6650 Jan 5 01:09 Gemfile.lock-e-e lrwxr-xr-x 1 usrname staff 18 Jan 5 00:37 README.rdoc - doc/README_FOR_APP -rw-r--r-- 1 usrname staff 283 Jan 5 01:10 Rakefile -rw-r--r-- 1 usrname staff 283 Jan 5 01:10 Rakefile-e -rw-r--r-- 1 usrname staff 283 Jan 5 01:09 Rakefile-e-e drwxr-xr-x 6 usrname staff 204 Jan 5 00:37 app drwxr-xr-x 5 usrname staff 170 Jan 5 01:10 autotest drwxr-xr-x 28 usrname staff 952 Jan 5 01:15 config -rw-r--r-- 1 usrname staff 173 Jan 5 01:10 config.ru -rw-r--r-- 1 usrname staff 173 Jan 5 01:10 config.ru-e -rw-r--r-- 1 usrname staff 173 Jan 5 01:09 config.ru-e-e

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• How to get root as '/' with Kohana3, base_url and mod rewrite.

  - by Drew

  Hi all! I've only just started using Kohana ( 3 hours ago), and so far it's blown my socks off (and I'm wearing slippers, so that's quite impressive). Right now, I have a controller 'Controller_FrontPage' with associated views and models and I'm trying to get it accesible from the root of my website (eg, http://www.mysite.com/). If I edit the default controller in the bootstrap from: Route::set('default', '(<controller>(/<action>(/<id>)))') ->defaults(array( 'controller' => 'welcome', 'action' => 'index', )); to 'controller' => '', I get an error, could not find controller_ (which makes sense), and if I change it to 'controller' => '/', I get an error, could not find controller_/ (which also makes sense). If I set 'controller' => 'FrontPage', everything works fine, but all my links (html::anchor(...)) point to http://www.mysite.com/FrontPage/*. Is there a way to have all the anchors point to http://www.mysite.com/*?

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• Need a tool to search large structure text documents for words, phrases and related phrases

  - by pitosalas

  I have to keep up with structured documents containing things such as requests for proposals, government program reports, threat models and all kinds of things like that. They are in techno-legalese as I would call them: highly structured, with section numbering and 3, 4 and 5 levels of nesting. All in English I need a more efficient way to locate those paragraphs of nuggets that matter to me. So what I’d like is kind of a local document index/repository, that would allow me to have some standing queries and easily locate sections in documents that talk about my queries. Here’s an example: I’d like to load in 10 large PDF files, each of say 100 pages. Each PDF contains English text, formatted very nicely into paragraphs and sections. I’d like to specify that I am interested in “blogging platforms”, “weaknesses in Ruby”, “localization and internationalization” Ideally then look at a list that showed the section of text, the name of the document, and other information that seemed to be related to and/or include the words and phrases I specified. I am sure something like this exists. I would call it something like document indexing, document comprehension or structured searching.

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• PostgreSQL, Foreign Keys, Insert speed & Django

  - by Miles

  A few days ago, I ran into an unexpected performance problem with a pretty standard Django setup. For an upcoming feature, we have to regenerate a table hourly, containing about 100k rows of data, 9M on the disk, 10M indexes according to pgAdmin. The problem is that inserting them by whatever method literally takes ages, up to 3 minutes of 100% disk busy time. That's not something you want on a production site. It doesn't matter if the inserts were in a transaction, issued via plain insert, multi-row insert, COPY FROM or even INSERT INTO t1 SELECT * FROM t2. After noticing this isn't Django's fault, I followed a trial and error route, and hey, the problem disappeared after dropping all foreign keys! Instead of 3 minutes, the INSERT INTO SELECT FROM took less than a second to execute, which isn't too surprising for a table <= 20M on the disk. What is weird is that PostgreSQL manages to slow down inserts by 180x just by using 3 foreign keys. Oh, disk activity was pure writing, as everything is cached in RAM; only writes go to the disks. It looks like PostgreSQL is working very hard to touch every row in the referred tables, as 3MB/sec * 180s is way more data than the 20MB this new table takes on disk. No WAL for the 180s case, I was testing in psql directly, in Django, add ~50% overhead for WAL logging. Tried @commit_on_success, same slowness, I had even implemented multi row insert and COPY FROM with psycopg2. That's another weird thing, how can 10M worth of inserts generate 10x 16M log segments? Table layout: id serial primary, a bunch of int32, 3 foreign keys to small table, 198 rows, 16k on disk large table, 1.2M rows, 59 data + 89 index MB on disk large table, 2.2M rows, 198 + 210MB So, am I doomed to either drop the foreign keys manually or use the table in a very un-Django way by defining saving bla_id x3 and skip using models.ForeignKey? I'd love to hear about some magical antidote / pg setting to fix this.

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• How to fetch and populate backbone model for Google Places JS API?

  - by code-gijoe

  I'm implementing a system that require access to Google Places JS API. I've been using rails for most of the project, but now I want to inject a bit of AJAX in one of my views. Basically it is a view that displays places near your location. For this, I'm using the JS API of Google places. A quick workflow would be: 1- The user inputs a text query and hits enter. 2- There is an AJAX call to request data from Google Places API. 3- The successful result is presented to the user. The problem is primarily in step 2. I want to use backbone for this but when I create a backbone model, it requests to the 'rootURL'. This wouldn't be a problem if the requests to Places was done from the server but it is not. A place call is done like this: service = new google.maps.places.PlacesService(map); service.nearbySearch(request, callback); Passing a callback function: function callback(results, status) { if (status == google.maps.places.PlacesServiceStatus.OK) { for (var i = 0; i < results.length; i++) { var place = results[i]; createMarker(results[i]); } } } Is it possible to override the 'fetch' method in backbone model and populate the model with the successful Places result? Is this a bad idea?

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• Python unittest (using SQLAlchemy) does not write/update database?

  - by Jerry

  Hi, I am puzzled at why my Python unittest runs perfectly fine without actually updating the database. I can even see the SQL statements from SQLAlchemy and step through the newly created user object's email -- ...INFO sqlalchemy.engine.base.Engine.0x...954c INSERT INTO users (user_id, user_name, email, ...) VALUES (%(user_id)s, %(user_name)s, %(email)s, ...) ...INFO sqlalchemy.engine.base.Engine.0x...954c {'user_id': u'4cfdafe3f46544e1b4ad0c7fccdbe24a', 'email': u'[email protected]', ...} > .../tests/unit_tests/test_signup.py(127)test_signup_success() -> user = user_q.filter_by(user_name='test').first() (Pdb) n ...INFO sqlalchemy.engine.base.Engine.0x...954c SELECT users.user_id AS users_user_id, ... FROM users WHERE users.user_name = %(user_name_1)s LIMIT 1 OFFSET 0 ...INFO sqlalchemy.engine.base.Engine.0x...954c {'user_name_1': 'test'} > .../tests/unit_tests/test_signup.py(128)test_signup_success() -> self.assertTrue(isinstance(user, model.User)) (Pdb) user <pweb.models.User object at 0x9c95b0c> (Pdb) user.email u'[email protected]' Yet at the same time when I login to the test database, I do not see the new record there. Is it some feature from Python/unittest/SQLAlchemy/Pyramid/PostgreSQL that I'm totally unaware of? Thanks. Jerry

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• Data Annotations on ViewModels or Domain Objects

  - by Ahmad

  Where would data annotations be more suitable: ViewModels or Domain Objects or Both I am struggling to decide where these will be more suited. I have not as yet fully utilized them but this question came to mind. From most of the examples I have seen, they are generally placed on Models and simply use the required attributes for validation using ModelState.IsValid. I have also seen another question on SO where the use of data annotations alone is not sufficient and advocate. Option 1 - I will still need to validate again in my service layer. ( I think that my service layer should be complete and this include validation, since its planned to be used elsewhere) Option 2 - How will I then get the benefits of the built in validation both client and server side. Option 3 - there will be a repetition of validation logic, however I was wondering if one could use a MetaData class approach that can be used for both ViewModels and Domain Objects. ( This is completely of the top of my head, so it may be nonsensical) I wonder if this question even makes sense. If not, can someone please help in understanding this better. Have I completely misunderstood the use of data annotations?

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• need advice on Zend framework Application architecture, or say approach dealing with modules

  - by simple

  Let me start with the things that I did and how am I using some things to get results I have set up modular structure as: application/ /configs /layouts /models /modules /users /profile /frontend /backend /controllers /views .... I write a plugin that does addes changes with FrontController-setModuleControllerDirectoryName() FrontController-addModuleDirectory() and It is all good I have a changed all the directories according weather admin page is requested in the url or not (it is some thing like /admin/some/some) Let's say I have a single layout for anything that is related to Profile viewing , in this case the "Profile" module. The Profile layout is divided into three parts In the layout I was pulling out the Profile/PhotoController 's index action with a action() $this->action('index', 'photo', 'profile'); Then I have faced few issues 1. Can get passed Params inside the Photo Controller when calling ( profile/profile/index); 2. found out that helper Action() is evil cause it starts another dispatching loop =) --- and now I am thinking that my approach on plugging in controllers modules into layout also evil =). anyhow how Should I deal with plugging in some controllers (another module controllers) into the layout ?

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• Populating dropdownlist in asp.net mvc doesn't seem to work for me...

  - by Pandiya Chendur

  I use a dropdownlist in one of my create.aspx but it some how doesnt seem to work... public IEnumerable<Materials> FindAllMeasurements() { var mesurements = from mt in db.MeasurementTypes select new Materials() { Id= Convert.ToInt64(mt.Id), Mes_Name= mt.Name }; return mesurements; } and my controller, public ActionResult Create() { var mesurementTypes = consRepository.FindAllMeasurements().AsEnumerable(); ViewData["MeasurementType"] = new SelectList(mesurementTypes, "Id", "Mes_Name"); return View(); } and my create.aspx has this, <p> <label for="MeasurementTypeId">MeasurementType:</label> <%= Html.DropDownList("MeasurementType", ViewData["MeasurementType"])%> <%= Html.ValidationMessage("MeasurementTypeId", "*") %> </p> When i execute this i got these errors, System.Web.Mvc.HtmlHelper<CrMVC.Models.Material>' does not contain a definition for 'DropDownList' and the best extension method overload 'System.Web.Mvc.Html.SelectExtensions.DropDownList(System.Web.Mvc.HtmlHelper, string, System.Collections.Generic.IEnumerable<System.Web.Mvc.SelectListItem>)' has some invalid arguments 2.cannot convert from 'object' to 'System.Collections.Generic.IEnumerable<System.Web.Mvc.SelectListItem>

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• Should I write more SQL to be more efficient, or less SQL to be less buggy?

  - by RenderIn

  I've been writing a lot of one-off SQL queries to return exactly what a certain page needs and no more. I could reuse existing queries and issue a number of SQL requests linear to the number of records on the page. As an example, I have a query to return People and a query to return Job Details for a person. To return a list of people with their job details I could query once for people and then once for each person to retrieve their job details. I've found that in most cases that solution returns things in a reasonable amount of time, but I don't know how well it will scale in my environment. Instead I've been writing queries to join people + job details, or people + salary history, etc. I'm looking at my models and I see how I could shave off maybe 30% of my code if I were to re-use existing queries. This is a big temptation. Is it a bad thing to go for reuse over efficiency in general or does it all come down to the specific situation? Should I first do it the easy way and then optimize later, or is it best to get the code knocked out while everything is fresh in my mind? Thoughts, experiences?

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• ASP.NET MVC Patterns

  - by Sam Striano

  Hello, I am fairly new to MVC, but after playing with it (MVC 3/Razor), I am hooked. I have a few questions: 1) What is the best, or most widely used pattern to develop MVC apps in? Repository, DDD, UOW? 2) I am using the Entity Framework 4, so could some please explain to me or point me to a good source that will explain the Repository Pattern w/EF4? Doesn't EF4 take place as the business layer and the data access layer? Does the Repository Pattern even provide a benefit? 3) Also, one last question, could someone explain the whole relationship between the Controller, the Model and the View? I get the basics, but maybe a little more in depth of the correct way to use it. View Models - Say I have a view that displays customer info, and one that edits it, should I have a view model and an edit model, or can the be passed around? 4) Examples?? Thanks for the help up front, $("Sam") ** EDIT ** Am I on the right track here: Public Class HomeController Inherits System.Web.Mvc.Controller Function Index(ByVal id As Integer) As ActionResult Return View(New HomeModel) End Function <HttpPost()> _ Function Index(ByVal Model As HomeModel) As ActionResult Return View(Model) End Function End Class Public Class HomeModel Private _Repository As IRepository(Of Customer) Public Property Customer As Customer Public Sub New() End Sub Public Sub New(ByVal ID As Integer) _Repository = New CustomerRepository Customer = _Repository.GetByID(ID) End Sub End Class Public Interface IRepository(Of T) Function GetByID(ByVal ID As Integer) As T Sub Add(ByVal Entity As T) Sub Delete(ByVal Entity As T) End Interface Public Class CustomerRepository Implements IRepository(Of Customer) Public Sub Add(ByVal Entity As Customer) Implements IRepository(Of Customer).Add End Sub Public Sub Delete(ByVal Entity As Customer) Implements IRepository(Of Customer).Delete End Sub Public Function GetByID(ByVal ID As Integer) As Customer Implements IRepository(Of Customer).GetByID Return New Customer With {.ID = ID, .FirstName = "Sam", .LastName = "Striano"} End Function End Class Public Class Customer Public Property ID As Integer Public Property FirstName As String Public Property LastName As String End Class

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• How do I do client-side form validation in jQuery?

  - by marcamillion

  I am trying to use this plugin: http://docs.jquery.com/Plugins/Validation Where #user_new is the id for my form, this is what my code looks like: $('#user_new').validate({ rules: { user[username]: "required", user[email]: { required: true, email: true } }, messages: { user[username]: "Please specify your name", user[email]: { required: "We need your email address to contact you", email: "Your email address must be in the format of [email protected]" } } }) Where these are how my input fields look when the page is rendered (generated by Rails): <input class="clearField curved" id="user_f_name" name="user[f_name]" size="30" type="text" value="First Name" /><br /> <input class="clearField curved" id="user_l_name" name="user[l_name]" size="30" type="text" value="Last Name" /><br /> <input class="clearField curved" id="user_username" name="user[username]" size="30" type="text" value="Username" /><br /> <input class="clearField curved" id="user_password" name="user[password]" size="30" type="password" value="Password" /><br /> <input class="clearField curved" id="user_password_confirmation" name="user[password_confirmation]" size="30" type="password" value="Password" /><br /> <input class="clearField curved" id="user_email" name="user[email]" size="30" type="text" value="Email Address" /><br /> I was just trying to validate username & email first. Then take it from there. For the life of me, I can't figure out how to specify the syntax and the rules for working with this plugin. Help!

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• NHibernate collections: many-to-many relationships

  - by Brad Heller

  I've got two models, a Product model and a ShoppingCart model. The ShoppingCart model has a collection of products as a property called Products (List). Here is the mapping for my ShoppingCart model. <class name="MyProject.ShoppingCart, MyProject" table="ShoppingCarts"> <id name="Id" column="Id"> <generator class="native" /> </id> <many-to-one name="Company" class="MyProject.Company, MyProject" column="CompanyId" /> <property name="ExternalId" column="GUID" generated="insert" /> <property name="Name" column="Name" /> <property name="Total" column="Total" /> <property name="CreationDate" column="CreationDate" generated="insert" /> <property name="UpdatedDate" column="UpdatedDate" generated="always" /> <bag name="Products" table="ShoppingCartContents" lazy="false"> <key column="ShoppingCartId" /> <many-to-many column="ProductId" class="MyProjectMyProject.Product, MyProject" fetch="join" /> </bag> </class> When I try to save to the DB, the ShoppingCart is saved, but the mapping rows in ShoppingCartContents aren't save, making me thing that there's an issue with the mapping. Where am I going wrong here?

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• Alloy MVC Framework Titanium Network (Model)

  - by flyingDuck

  I'm trying to authenticate using the Model in Alloy. I have been trying to figure this problem out since yesterday. If anybody could help me, I'd really appreciate it. So, I have a view login.xml, then a controller login.js. The login.js contains the following function: var user = Alloy.Models.user; //my user.js model function login(e) { if($.username.value !== '' && $.password.value !== ''){ if(user.login($.username.value, $.password.value)){ Alloy.createController('home').getView().open(); $.login.close(); } }else{ alert('Username and/or Password required!'); } } Then in my user.js model, it's like this: extendModel : function(Model) { _.extend(Model.prototype, { login: function(username, password) { var first_name, last_name, email; var _this = this; var url = 'http://myurl.com/test.php'; var auth = Ti.Network.createHTTPClient({ onerror: function(e){ alert(e.error); }, onload: function(){ var json = this.responseText; var response = JSON.parse(json); if(response.logged == true){ first_name = response.f_name; last_name = response.l_name; email = response.email; _this.set({ loggedIn: 1, username: email, realname: first_name + ' ' + last_name, email: email, }); _this.save(); }else{ alert(response.message); } }, }); auth.open('POST', url); var params = { usernames: username, passwords: password, }; auth.send(params); alert(_this.get('email')); //alert email }, }); When I click on login in login.xml it calls the function login in index.js. So, now my problem is that, when I click the button for the first time, I get an empty alert from alert(_this.get('email')), but then when I click the button the second time, everything works fine, it alerts the email. I have no idea what's going on. Thank you for the help.

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• Why are symbols not frozen strings?

  - by Alex Chaffee

  I understand the theoretical difference between Strings and Symbols. I understand that Symbols are meant to represent a concept or a name or an identifier or a label or a key, and Strings are a bag of characters. I understand that Strings are mutable and transient, where Symbols are immutable and permanent. I even like how Symbols look different from Strings in my text editor. What bothers me is that practically speaking, Symbols are so similar to Strings that the fact that they're not implemented as Strings causes a lot of headaches. They don't even support duck-typing or implicit coercion, unlike the other famous "the same but different" couple, Float and Fixnum. The mere existence of HashWithIndifferentAccess, and its rampant use in Rails and other frameworks, demonstrates that there's a problem here, an itch that needs to be scratched. Can anyone tell me a practical reason why Symbols should not be frozen Strings? Other than "because that's how it's always been done" (historical) or "because symbols are not strings" (begging the question). Consider the following astonishing behavior: :apple == "apple" #=> false, should be true :apple.hash == "apple".hash #=> false, should be true {apples: 10}["apples"] #=> nil, should be 10 {"apples" => 10}[:apples] #=> nil, should be 10 :apple.object_id == "apple".object_id #=> false, but that's actually fine All it would take to make the next generation of Rubyists less confused is this: class Symbol < String def initialize *args super self.freeze end (and a lot of other library-level hacking, but still, not too complicated) See also: http://onestepback.org/index.cgi/Tech/Ruby/SymbolsAreNotImmutableStrings.red http://www.randomhacks.net/articles/2007/01/20/13-ways-of-looking-at-a-ruby-symbol Why does my code break when using a hash symbol, instead of a hash string? Why use symbols as hash keys in Ruby? What are symbols and how do we use them? Ruby Symbols vs Strings in Hashes Can't get the hang of symbols in Ruby

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• nullable bool is being passed to the controller null all the time regardless of the value

  - by user1807954

  I'm trying to pass a nullable bool to my controller. But when I pass the bool value from my view to the controller, it's being passed null all the time regardless of the value it has in my view. Here is my view: @model Cars.Models.Car @using (Html.BeginForm("Index", "Home", FormMethod.Post, new { id = "CategoryFormID"})) { <label>Convertible:</label> <input type="checkbox" id="ConvertibleID" name="convertible"/> <button type="submit" name="submit" value="search" id="SubmitID">Search</button> } And my controller: [HttpPost] public ActionResult Index(bool? convertible){ var cars = from d in db.Car select d; if (convertible.HasValue) { cars = cars.Where(x => x.Convertible == convertible); } return View("SearchResult", cars); } I also have other fields such as drop down lists and text fields, but they're being passed flawless. Any help would be really appreciated. Update: Thank you for your fast responds. However, I did try giving it a value="True" as you guys suggested. There is only 2 options now: null and true. But my intention is to use nullable bool to have three options: null (when user doesn't touch the checkbox), true(checked) and false(unchecked). I know it sounds not smart and silly, but I'm just trying to figure out how nullable bool is working, and what is the intention of having such a thing in C# (I'm new with C#). I was wondering if it is possible to do so with just checkbox and without the use of dropdownlist or radio buttons.

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• Controller class not available in Add View ASP.NET MVC

  - by Tassadaque

  Hi I have created the following controller i want to add view that should have the data access class UserMagnament.Controller.menuitems but when i add view by right clicking on view folder,it is not showing "UserMagnament.Controller.menuitems" in add data class using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using UserManagement.Models; namespace UserManagement.Controllers { public class menuitems { EvoLetDataContext db1 = new EvoLetDataContext(); public menuitems() { } public IQueryable<UMUserType> menuitems() { return db1.UMUserTypes; //this.Packages = _SysPackage; //this.Modules = _SysModule; } public List<SysPackage> Packages { get; private set; } public List<SysModule> Modules { get; private set; } } public class Default1Controller : Controller { // // GET: /Default1/ public ActionResult Index() { return View(new menuitems()); } } }

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• Problem using Lazy<T> from within a generic abstract class

  - by James Black

  I have a generic class that all my DAO classes derive from, which is defined below. I also have a base class for all my entities, but that is not generic. The method GetIdOrSave is going to be a different type than how I defined SabaAbstractDAO, as I am trying to get the primary key to fulfill the foreign key relationships, so this function goes out to either get the primary key or save the entity and then get the primary key. The last code snippet has a solution on how it will work if I get rid of the generic part, so I think this can be solved by using variance, but I can't figure out how to write an interface that will compile. public abstract class SabaAbstractDAO<T> { ... public K GetIdOrSave<K>(K item, Lazy<SabaAbstractDAO<BaseModel>> lazyitemdao) where K : BaseModel { if (item != null && item.Id.IsNull()) { var itemdao = lazyitemdao.Value; item.Id = itemdao.retrieveID(item); if (item.Id.IsNull()) { return itemdao.SaveData(item); } } return item; } } I am getting this error, when I try to compile: Argument 2: cannot convert from 'System.Lazy<ORNL.HRD.LMS.Dao.SabaCourseDAO>' to 'System.Lazy<ORNL.HRD.LMS.Dao.SabaAbstractDAO<ORNL.HRD.LMS.Models.BaseModel>>' I am trying to call it this way: GetIdOrSave(input.OfferingTemplate, new Lazy<SabaCourseDAO>( () => { return new SabaCourseDAO() { Dao = Dao }; }) ); If I change the definition to this, it works. public K GetIdOrSave<K>(K item, Lazy<SabaCourseDAO> lazyitemdao) where K : BaseModel { So, how can I get this to compile using variance (if needed) and generics, so I can have a very general method that will only work with BaseModel and AbstractDAO<BaseModel>? I expect I should only need to make the change in the method and perhaps abstract class definition, the usage should be fine.

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• How to use associated Model as datasource for DataView

  - by Chris Gilbert

  I have a Model structure as shown below and I want to know how to use the Bookings array as the datasource of my DataView. Model Structure: Client ClientId Name Bookings (HasManyAssociation) Contacts (HasManyAssociation) AjaxProxy JsonReader (ImplicitIncludes is set to true so child models are created with one call) Booking BookingNodeId BookingDetails Contact ContactNodeId ContactDetails The above gives me a data structure as follows: Client Bookings[ Booking Booking ] Contacts[ Contact Contact ] What I want to be able to do is either, create a Store from my Bookings array and then use that store as the datasource for my DataView OR directly use the Bookings array as the datasource (I don't really care how I do it to be honest). If I setup the AjaxProxy on my Booking model it works fine but then obviously I cannot automatically create my Client and Contacts when I load my JSON. It seems to me to make sense that the Client model, being the top level model hierarchically, is the one to load the data. EDIT: I figured it out as follows (with special thanks to handet87 below for his dataview.setStore() pointer). The key in this case is to know that creating the relationship actually sets up another store called, in this case BookingsStore and ContactsStore. All I needed to do was dataview.setStore("BookingsStore")

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• Type or namespace could not be found

  - by Jason Shultz

  I'm using LINQ to SQL to connect my database to my home page. I created my datacontext (named businessModel.dbml) In it I have two tables named Category and Business. In home controller I reference the model and attempt to return to the view the table: var dataContext = new businessModelDataContext(); var business = from b in dataContext.Businesses select b; ViewData["WelcomeMessage"] = "Welcome to Jerome, Arizona!"; ViewData["MottoMessage"] = "Largest Ghost Town in America!"; return View(business); and in the view I have this: <%@ Import Namespace="WelcomeToJerome.Models" %> and <% foreach (business b in (IEnumerable)ViewData.Model) { %> <li><%= b.Title %></li> <% } %> Yet, in the view business is cursed with the red underline and say's that The type or namespace name 'business' could not be found (are you missing a using directive or an assembly reference?) What am I doing wrong? This has had me stumped all afternoon. link to all the code in pastebin: http://pastebin.com/es4RnS2q

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