code layout - Page 27 - Developer IT

How to review code that you do not understand?

- by John Isaacks

I have been given the role to improve development in our company. The first thing I wanted to start was code reviews since that has never been done here before. There are 3 programmers in our company. I am a web programmer, my known languages are mainly PHP, ActionScript and JavaScript. The other 2 developers write internal applications in VB.net We have been doing code reviews for a couple weeks now. I find it hard to understand VB code. So when they say what its doing, for the most part I just have to take their word for it. If I do see something that looks wrong, I explain my opinion and I explain how I would address it in one of the languages I know. Sometimes my suggestions are welcomed but many times I am told things like "this is the best way of doing it in this language" or "that doesn't apply to this language" or similar things of that nature. This may be true, but without knowing the language I am not sure how to confirm or refute these claims. I know one possible solution would be to learn vb so I can do better code reviews. I really have no interest in learning vb (especially since I have a list of other technologies I am trying to learn for my own projects) and would like to keep this as a last resort but it is an option. Another idea that came to me is, they both have interest in C# and so do I. Its relative to them because its .net and relative to me because its more similar to the languages I know. Yet it is new to all of us. I thought about the benefits of us all collaborating on a pet C#.net project and reviewing each others code from that. I guess theres also the possibility hiring a consultant to come in and give us some code reviews. What would you recommend I do in this situation.

Read the article

How do you use blank lines in your code ?

- by Matthieu M.

There has been a few remarks about white space already in discussion about curly braces placements. I myself tend to sprinkle my code with blank lines in an attempt to segregate things that go together in "logical" groups and hopefully make it easier for the next person to come by to read the code I just produced. In fact, I would say I structure my code like I write: I make paragraphs, no longer than a few lines (definitely shorter than 10), and try to make each paragraph self-contained. For example: in a class, I will group methods that go together, while separating them by a blank line from the next group. if I need to write a comment I'll usually put a blank line before the comment in a method, I make one paragraph per step of the process All in all, I rarely have more than 4/5 lines clustered together, meaning a very sparse code. I don't consider all this white space a waste because I actually use it to structure the code (as I use the indentation in fact), and therefore I feel it worth the screen estate it takes. For example: for (int i = 0; i < 10; ++i) { if (i % 3 == 0) continue; array[i] += 2; } I consider than the two statements have clear distinct purposes and thus deserve to be separated to make it obvious. So, how do you actually use (or not) blank lines in code ?

Read the article

How do you structure your shared code so that it is "re-findable" for new developers?

- by awmckinley

I started working at my current job about 8 months ago, and its been one of the best experiences I've had as a young programmer. It's a small company, and both my co-developers are brilliant guys. One of the practices that they both have been encouraging is lots of code-reuse. Our code base is mainly C#, and we're using a centralized revision control system. The way the repository is currently structured, there is a single folder in which all shared class libraries are placed (along with unit tests for each library), and our revision control system allows for sharing or linking those libraries out to other projects. What I'm trying to understand at this point is how the current structure of the folder can be made more conducive for finding those libraries again. I've talked to the other developers about this, and they agree that it's gotten a little messy. I find that I am sometimes "reinventing the wheel" because I didn't realize that there was an existing piece of code that solved a particular problem. The issue is complicated further by the fact that we're sharing some code between ASP.NET MVC2, WinForms, and Windows CE projects, and sharing code between applications built against multiple versions of .NET. How do other people approach this? Is the answer in naming the libraries in a certain way or is it preferable to invest in some code-search software? Is the answer in doc comments? Should we be sharing libraries at all or should we simply branch the class libraries for re-use? Thanks for any and all help!

Read the article

How to get feedback from the community on large chunks of code?

- by MainMa

Code Review.SE is great when you need feedback on a precise, short piece of code. But where to get similar feedback about the code itself when: you have thousands of LOC, don't have colleagues in your workplace ready or willing to review the code¹, don't have thousands of dollars to spend for a professional review by a third party developer?² Places like CodePlex are a good idea to get your project known³, but from what I've seen, the feedback you get on known projects are consumer feedback, i.e. concerns the bugs and feature requests, not the quality of the source code itself. What are the social way to get the community involved in the code review of the codebase of a certain size for an open source project which doesn't have the scale of Firefox or similar products? ¹ Which is the case for most personal and open source projects, or projects done in companies where the practice of regular and complete code review is nonexistent. ² Which is, again, the case for most personal and open source projects. ³ Even if too many projects published on CodePlex never get known, either because nobody cares or because they are presented not very well.

Read the article

Does it make sense to write tests for legacy code when there is no time for a complete refactoring?

- by is4

I usually try to follow the advice of the book Working Effectively with Legacy Code. I break dependencies, move parts of the code to @VisibleForTesting public static methods and to new classes to make the code (or at least some part of it) testable. And I write tests to make sure that I don't break anything when I'm modifying or adding new functions. A colleague says that I shouldn't do this. His reasoning: The original code might not work properly in the first place. And writing tests for it makes future fixes and modifications harder since devs have to understand and modify the tests too. If it's GUI code with some logic (~12 lines, 2-3 if/else block, for example), a test isn't worth the trouble since the code is too trivial to begin with. Similar bad patterns could exist in other parts of the codebase, too (which I haven't seen yet, I'm rather new); it will be easier to clean them all up in one big refactoring. Extracting out logic could undermine this future possibility. Should I avoid extracting out testable parts and writing tests if we don't have time for complete refactoring? Is there any disadvantage to this that I should consider?

Read the article

Android - Can display a single Activity using two layout.xml files?

- by Avadhani

I had developed Android app having some screens with common UI format. The format in top-down approach is: Title Header (Two buttons, ImageView) Content Area- It will differ among Activities (contains ListView, Tabs, Buttons, TextView, WebView....) Footer Layout (Relative Layout with three Imagebuttons) I want to reformat the code in such a way that one xml contains Title Header and Footer Layout and other xml contains ListView,Tabs, Buttons.. based on the usage. Can i acheive this? Please help me with sample code/links....

Read the article

Magento - createBlock() in controller, can I access this in layout.xml?

- by pspahn

I have an index controller with a view action that does the following: echo $this->getLayout() ->createBlock('core/template','builder') ->setTemplate('pages/builder/view.phtml') ->setHeaderText($extra->getHeaderText()) ->setFooterText($extra->getFooterText()) ->setProducts($collection) ->toHtml(); Based on this, I am trying to perform layout updates in builder.xml (which is being set in the module's config.xml). However, I am not sure if you can target blocks instantiated in this manner. Based on the above block creation, am I able to perform the following: <layout version="0.1.0"> <builder_index_view>  <reference name="builder"> <block type="page/html_header" name="builder.header" as="builder.header" template="pages/builder/header.phtml"/> </reference> </builder_index_view> </layout>

Read the article

10 CSS Grid Layout Generators

- by Jyoti

There are a lot of online generators which are of no use to any designers, however some can help designers to an extent. Some example of online generators are favicon generators, background generators, button generators, and badge generators. Some of the useful kinds are the ones that solve one purpose with quick and easy steps, especially useful for new designers, following is a list of some useful CSS grid layout generators. Grid Layout Generator By PageColumn: Blueprint Grid CSS Generator: Grid Generator By NetProtozo: Grid Generator By DegisnByGrid: Grid System Generator: YUI CSS Grid Builder: Variable Grid System: Firdamatic: CSS Sourced Ordered Variable Border Columed Page Maker: Grid Designer:

Read the article

Silverlight Grid Layout is pain

- by brainbox

I think one of the biggest mistake of Silverlight and WPF is its Grid layout.Imagine you have a data form with 2 columns and 5 rows. You need to place new row after the first one. As a result you need to rewrite Grid.Rows and Grid.Columns in all rows belows. But the worst thing of such approach is that it is static. So you need predefine all your rows and columns. As a result creating of simple dynamic datagrid or dataform become impossible... So the question if why best practices of HTML and Adobe Flex were dropped????If anybody have tried to port Flex Grid layout to silverlight please mail me or drop a comment.

Read the article

Visualizing Nodes and Edges with Microsoft Automatic Graph Layout

Learn about the Microsoft Automatic Graph Layout using a Windows Presentation Foundation (WPF) sample application.

Read the article

Visualizing Nodes and Edges with Microsoft Automatic Graph Layout

Learn about the Microsoft Automatic Graph Layout using a Windows Presentation Foundation (WPF) sample application.

Read the article

grid layout default on wordpress theme

- by nathan philpott

I'm having trouble with a multi-layout option on a wordpress theme sight http://sight.wpshower.com/ the traffic have the option of a grid or a list layout at the click of a button. at present the list layout is default. I am interested in making the grid layout default . this is some of the php, i tried simply swapping the word grid for list but although this does work to an extent , if done on the loop.php page it removes the a:hover functions on the post boxes in the grid format. also if done on the index.php it switches buttons on the main index page. any ideas?? loop.php <div id="loop" class="<?php if ($_COOKIE['mode'] == 'grid') echo 'grid'; else echo 'list'; ?> clear"> <?php while ( have_posts() ) : the_post(); ?> <div <?php post_class('post clear'); ?> id="post_<?php the_ID(); ?>"> <?php if ( has_post_thumbnail() ) :?> <a href="<?php the_permalink() ?>" class="thumb"><?php the_post_thumbnail('thumbnail', array( 'alt' => trim(strip_tags( $post->post_title )), 'title' => trim(strip_tags( $post->post_title )), )); ?></a> <?php endif; ?> <div class="post-category"><?php the_category(' / '); ?></div> <h2><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></h2>  <?php edit_post_link( __( 'Edit entry'), '<em>• </em>'); ?> <div class="post-content"><?php if (function_exists('smart_excerpt')) smart_excerpt(get_the_excerpt(), 55); ?></div> </div> <?php endwhile; ?> </div> <?php endif; ?> index.php <?php get_header(); ?> <div class="content-title"> Projects <a href="javascript: void(0);" id="mode"<?php if ($_COOKIE['mode'] == 'grid') echo ' class="flip"'; ?>></a> </div> <?php query_posts(array( 'post__not_in' => $exl_posts, 'paged' => $paged, ) ); ?> <?php get_template_part('loop'); ?> <?php wp_reset_query(); ?> <?php get_template_part('pagination'); ?> <?php get_footer(); ?>

Read the article

PHP city-sim castle layout

- by Gert

I am currently contemplating the layout system for my php based game but i've run into a couple of worries. So my idea is a 9X9 grid where the center 3X3 are inner castle. The inner castle will be 6X6 if you enter it(click on it). and with the option to expand the inner castle converting one of the 9X9 tiles to a 4X4 inner castle tile. So here is my question: What is the best way to tackle this type of layout? my original idea was a 18X18 grid and saving it in the db as (idCastle, Y, X) where X is a string of 18 numbers long telling me if the tile is an inner/outer tile or a inner/outer building. but i am not really fond of this idea and would like to hear some other ideas on how to tackle this. Thanks in Advance, Gert

Read the article

Splitting Logic, Data, Layout and "Hacks"

- by fjdumont

Sure, we all heard of programming patterns such as MVVM, MVC and such. But that isn't really what I'm looking into as Layout, Data and Logic is already pretty much split up (XML-Layout markup, Database, insert your language of choice here). The platform I am developing for is hard to maintain over the updated versions and older OSes. The project significantly grew up over the last few months and dealing with different platform versions really is a pain. For example simply disabling an user interface control for all existing versions took me around 40 lines of code in the logic layer, wrangling around with invocation, delegation, singletons that provide UI handling and so on. Is there a clean way to keep track of those "hacks" by maybe excluding it into separate classes or even packages? Should I overwrite existing framework code in order to handle my requirements correctly? If so, does that concept have a name?

Read the article

Set Layout in Silverlight

The Blog teach to how to position the controls in proper layout as silverlight doesnot provide you drap n drop the controls

Read the article

New Layout Features In ASP.NET and WinForms Scheduler Reporting - v2010.1

Check out these 2 new features of the ASPxScheduler and XtraScheduler that helps you improve appointment layout and display. Quick recap: Our Scheduler controls use the powerful XtraReports Suite for exporting and printing. This gives you added benefits for more flexibility, control and features. Read the 'ASP.NET Calendar SchedulingNew DevExpress Reporting Integration' post to learn more. CanShrink And CanGrow The 2 new layout properties are called CanShrink and CanGrow: CanShrink...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

Read the article

New Layout Features In ASP.NET and WinForms Scheduler Reporting - v2010.1

Check out these 2 new features of the ASPxScheduler and XtraScheduler that helps you improve appointment layout and display. Quick recap: Our Scheduler controls use the powerful XtraReports Suite for exporting and printing. This gives you added benefits for more flexibility, control and features. Read the 'ASP.NET Calendar SchedulingNew DevExpress Reporting Integration' post to learn more. CanShrink And CanGrow The 2 new layout properties are called CanShrink and CanGrow: CanShrink...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

Read the article

ASP.NET Pivot Grid Control Supports New Layout - v2010 vol 1

The ASPxPivotGrid will now support a slick new feature that will help save you screen space: Compact Layout for Hierarchical Row Values With DXperience v2010 vol 1, you can create compact layouts for hierarchical pivot table row values (this capability is also available in the WinForms and WPF versions of this control). The compact layout allows you get more space horizontally without sacrificing the distinction between the hierarchical row values: DXperience? What's That? DXperience is the...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

Read the article

Laravel - public layout not needed in every function

- by fischer

I have just recently started working with Laravel. Great framework so far! However I have a question. I am using a layout template like this: public $layout = 'layouts.private'; This is set in my Base_Controller: public function __construct(){ //Styles Asset::add('reset', 'css/reset.css'); Asset::add('main', 'css/main.css'); //Scripts Asset::add('jQuery', 'http://ajax.googleapis.com/ajax/libs/jquery/1.8.1/jquery.min.js'); //Switch layout template according to the users auth credentials. if (Auth::check()) { $this -> layout = 'layouts.private'; } else { $this -> layout = 'layouts.public'; } parent::__construct(); } However I get an error exception now when I try to access functions in my diffrent controllers, which should not call any view, i.e. when a user is going to login: class Login_Controller extends Base_Controller { public $restful = true; public function post_index() { $user = new User(); $credentials = array('username' => Input::get('email'), 'password' => Input::get('password')); if (Auth::attempt($credentials)) { } else { } } } The error I get, is that I do not set the content of the different variables in my public $layout. But since no view is needed in this function, how do I tell Laravel not to include the layout in this function? The best solution that I my self have come a cross (don't know if this is a bad way?) is to unset($this -> layout); from function post_index()... To sum up my question: how do I tell Laravel not to include public $layout in certain functions, where a view is not needed? Thanks in advance, fischer

Read the article

Why is code quality not popular?

- by Peter Kofler

I like my code being in order, i.e. properly formatted, readable, designed, tested, checked for bugs, etc. In fact I am fanatic about it. (Maybe even more than fanatic...) But in my experience actions helping code quality are hardly implemented. (By code quality I mean the quality of the code you produce day to day. The whole topic of software quality with development processes and such is much broader and not the scope of this question.) Code quality does not seem popular. Some examples from my experience include Probably every Java developer knows JUnit, almost all languages implement xUnit frameworks, but in all companies I know, only very few proper unit tests existed (if at all). I know that it's not always possible to write unit tests due to technical limitations or pressing deadlines, but in the cases I saw, unit testing would have been an option. If a developer wanted to write some tests for his/her new code, he/she could do so. My conclusion is that developers do not want to write tests. Static code analysis is often played around in small projects, but not really used to enforce coding conventions or find possible errors in enterprise projects. Usually even compiler warnings like potential null pointer access are ignored. Conference speakers and magazines would talk a lot about EJB3.1, OSGI, Cloud and other new technologies, but hardly about new testing technologies or tools, new static code analysis approaches (e.g. SAT solving), development processes helping to maintain higher quality, how some nasty beast of legacy code was brought under test, ... (I did not attend many conferences and it propably looks different for conferences on agile topics, as unit testing and CI and such has a higer value there.) So why is code quality so unpopular/considered boring? EDIT: Thank your for your answers. Most of them concern unit testing (and has been discussed in a related question). But there are lots of other things that can be used to keep code quality high (see related question). Even if you are not able to use unit tests, you could use a daily build, add some static code analysis to your IDE or development process, try pair programming or enforce reviews of critical code.

Read the article

CSS Code is not working in IE 6.

- by ashish bhatt

this is the code for menu CSS code. It will work on Firefox but not in IE6. .menu li a:hover .menu ul li:hover a{ background-image:url(images/ye.jpg); color:#000000; text-decoration:none; }

Read the article

Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

- by mortezam

This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail { public int BillingDetailId { get; set; } public string Owner { get; set; } public string Number { get; set; } } public class BankAccount : BillingDetail { public string BankName { get; set; } public string Swift { get; set; } } public class CreditCard : BillingDetail { public int CardType { get; set; } public string ExpiryMonth { get; set; } public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext { public DbSet<BillingDetail> BillingDetails { get; set; } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<BankAccount>().Map(m => { m.MapInheritedProperties(); m.ToTable("BankAccounts"); }); modelBuilder.Entity<CreditCard>().Map(m => { m.MapInheritedProperties(); m.ToTable("CreditCards"); }); } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping { public class EntityMappingConfiguration<TEntityType> where TEntityType : class { public ValueConditionConfiguration Requires(string discriminator); public void ToTable(string tableName); public void MapInheritedProperties(); } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) { BankAccount bankAccount = new BankAccount(); CreditCard creditCard = new CreditCard() { CardType = 1 }; context.BillingDetails.Add(bankAccount); context.BillingDetails.Add(creditCard); context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail { [DatabaseGenerated(DatabaseGenerationOption.None)] public int BillingDetailId { get; set; } public string Owner { get; set; } public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>() .Property(p => p.BillingDetailId) .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) { BankAccount bankAccount = new BankAccount() { BillingDetailId = 1 }; CreditCard creditCard = new CreditCard() { BillingDetailId = 2, CardType = 1 }; context.BillingDetails.Add(bankAccount); context.BillingDetails.Add(creditCard); context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

Read the article

Getting Parent Layout in Qt

- by Austin

Hi, quick question. Is there any way to (easily) retrieve the parent layout of a widget in Qt? PS: QObject::parent() won't work, for logical reasons. EDIT: I'm positive the widget has a parent layout, because I added it to a layout earlier in the code. Now, I have many other layouts in the window and while it is possible for me to keep track of them, I just want to know if there is an easy and clean way to get the parent layout. EDIT2: Sorry, "easy and clean" was probably not the best way of putting. I meant using the Qt API. EDIT3: I'm adding the widget to the layout like this: QHBoxLayout* layout = new QHBoxLayout; layout-addWidget(button);

Read the article

How to build our own java custom layout

- by nguyendat

Please help me how to creat own custom layout, container, component, layout manager... Example: Containers and Layout Managers Create a window frame. Nest panels within a frame for better layout control. Create and display buttons in a panel. List two component attributes that are controlled by a layout manager. Set the layout manager for a container. Place components in a panel using BorderLayout, GridLayout, and FlowLayout. Name one advantage of each of the layout managers. Create panels with titles. i was search on google but can't find any that match my requirement Thanks for your help

Read the article

Using multiple column layout with HTML 5 and CSS 3

- by nikolaosk

This is going to be the fourth post in a series of posts regarding HTML 5. You can find the other posts here , here and here.In this post I will provide a hands-on example with HTML 5 and CSS 3 on how to create a page with multiple columns and proper layout.I will show you how to use CSS 3 to create columns much easier than relying on DIV elements and the float CSS rule.I will also show you how to use browser-specific prefix rules (-ms for Internet Explorer and -moz for Firefox ) for browsers that do not fully support CSS 3.In order to be absolutely clear this is not (and could not be) a detailed tutorial on HTML 5. There are other great resources for that.Navigate to the excellent interactive tutorials of W3School.Another excellent resource is HTML 5 Doctor.Two very nice sites that show you what features and specifications are implemented by various browsers and their versions are http://caniuse.com/ and http://html5test.com/. At this times Chrome seems to support most of HTML 5 specifications.Another excellent way to find out if the browser supports HTML 5 and CSS 3 features is to use the Javascript lightweight library Modernizr.In this hands-on example I will be using Expression Web 4.0.This application is not a free application. You can use any HTML editor you like.You can use Visual Studio 2012 Express edition. You can download it here.I will create a simple page with information about HTML 5, CSS 3 and JQuery. This is the full HTML 5 code. <!DOCTYPE html><html lang="en"> <head> <title>HTML 5, CSS3 and JQuery</title> <meta http-equiv="Content-Type" content="text/html;charset=utf-8" > <link rel="stylesheet" type="text/css" href="style.css"> </head> <body> <div id="header"> <h1>Learn cutting edge technologies</h1> <p>HTML 5, JQuery, CSS3</p> </div> <div id="main"> <div id="mainnews"> <div> <h2>HTML 5</h2> </div> <div> <p> HTML5 is the latest version of HTML and XHTML. The HTML standard defines a single language that can be written in HTML and XML. It attempts to solve issues found in previous iterations of HTML and addresses the needs of Web Applications, an area previously not adequately covered by HTML. </p> <div class="quote"> <h4>Do More with Less</h4> <p> jQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development. </p> </div> <p> The HTML5 test(html5test.com) score is an indication of how well your browser supports the upcoming HTML5 standard and related specifications. Even though the specification isn't finalized yet, all major browser manufacturers are making sure their browser is ready for the future. Find out which parts of HTML5 are already supported by your browser today and compare the results with other browsers. The HTML5 test does not try to test all of the new features offered by HTML5, nor does it try to test the functionality of each feature it does detect. Despite these shortcomings we hope that by quantifying the level of support users and web developers will get an idea of how hard the browser manufacturers work on improving their browsers and the web as a development platform.</p> </div> </div> <div id="CSS"> <div> <h2>CSS 3 Intro</h2> </div> <div> <p> Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation semantics (the look and formatting) of a document written in a markup language. Its most common application is to style web pages written in HTML and XHTML, but the language can also be applied to any kind of XML document, including plain XML, SVG and XUL. </p> </div> </div> <div id="CSSmore"> <div> <h2>CSS 3 Purpose</h2> </div> <div> <p> CSS is designed primarily to enable the separation of document content (written in HTML or a similar markup language) from document presentation, including elements such as the layout, colors, and fonts.[1] This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple pages to share formatting, and reduce complexity and repetition in the structural content (such as by allowing for tableless web design). </p> </div> </div> </div> <div id="footer"> <p>Feel free to google more about the subject</p> </div> </body> </html> The markup is very easy to follow. I have used some HTML 5 tags and the relevant HTML 5 doctype.The CSS code (style.css) follows body{ line-height: 30px; width: 1024px; background-color:#eee; } p{ font-size:17px; font-family:"Comic Sans MS" } p,h2,h3,h4{ margin: 0 0 20px 0; } #main, #header, #footer{ width: 100%; margin: 0px auto; display:block; } #header{ text-align: center; border-bottom: 1px solid #000; margin-bottom: 30px; } #footer{ text-align: center; border-top: 1px solid #000; margin-bottom: 30px; } .quote{ width: 200px; margin-left: 10px; padding: 5px; float: right; border: 2px solid #000; background-color:#F9ACAE; } .quote :last-child{ margin-bottom: 0; } #main{ column-count:2; column-gap:20px; column-rule: 1px solid #000; -moz-column-count: 2; -webkit-column-count: 2; -moz-column-gap: 20px; -webkit-column-gap: 20px; -moz-column-rule: 1px solid #000; -webkit-column-rule: 1px solid #000; } All the rules in the css code are pretty simple. The layout is achieved with that CSS rule #main{ column-count:2; column-gap:20px; column-rule: 1px solid #000; -moz-column-count: 2; -webkit-column-count: 2; -moz-column-gap: 20px; -webkit-column-gap: 20px; -moz-column-rule: 1px solid #000; -webkit-column-rule: 1px solid #000; Do note the column-count,column-gap and column-rule properties. These properties make the two column layout possible.Please have a look at the picture below to see why I used prefixes for Chrome (webkit) and Firefox(moz).It clearly indicates that the CSS 3 column layout are not supported from Firefox and Chrome. Finally I test my simple HTML 5 page using the latest versions of Firefox,Internet Explorer and Chrome. In my machine I have installed Firefox 15.0.1.Have a look at the picture below to see how the page looks I have installed Google Chrome 21.0 in my machine.Have a look at the picture below to see how the page looks Have a look at the picture below to see how my page looks in IE 10. My page looks the same in all browsers. Hope it helps!!!

Search Results

Search found 91732 results on 3670 pages for 'code layout'.

Page 27/3670 | < Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34 | Next Page >

- by John Isaacks

- by Matthieu M.

- by awmckinley

- by MainMa

- by is4

- by Avadhani

- by pspahn

- by Jyoti

- by brainbox

- by nathan philpott

- by Gert

- by fjdumont

- by fischer

- by Peter Kofler

- by ashish bhatt

- by mortezam

- by Austin

- by nguyendat

- by nikolaosk

< Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34 | Next Page >