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  • My View on ASP.NET Web Forms versus MVC

    - by Ricardo Peres
    Introduction A lot has been said on Web Forms and MVC, but since I was recently asked about my opinion on the subject, here it is. First, I have to say that I really like both technologies and I don’t think any is going away – just remember SharePoint, which is built on top of Web Forms. I see them as complementary, targeting different needs and leveraging different skills. Let’s go through some of their differences. Rapid Application Development Rapid Application Development (RAD) is the development process by which you have an Integrated Development Environment (IDE), a visual design surface and a toolbox, and you drag components from the toolbox to the design surface and set their properties through a property inspector. It was introduced with some of the earliest Windows graphical IDEs such as Visual Basic and Delphi. With Web Forms you have RAD out of the box. Visual Studio offers a generally good (and extensible) designer for the layout of pages and web user controls. Designing a page may simply be about dragging controls from the toolbox, setting their properties and wiring up some events to event handlers, which are implemented in code behind .NET classes. Most people will be familiar with this kind of development and enjoy it. You can see what you are doing from the beginning. MVC also has designable pages – called views in MVC terminology – the problem is that they can be built using different technologies, some of which, at the moment (MVC 4) do not support RAD – Razor, for example. I believe it is just a matter of time for that to be implemented in Visual Studio, but it will mostly consist on HTML editing, and until that day comes, you have to live with source editing. Development Model Web Forms features the same development model that you are used to from Windows Forms and other similar technologies: events fired by controls and automatic persistence of their properties between postbacks. For that, it uses concepts such as view state, which some may love and others may hate, because it may be misused quite easily, but otherwise does its job well. Another fundamental concept is data binding, by which a collection of data can be fed to a control and have it render that data somehow – just thing of the GridView control. The focus is on the page, that’s where it all starts, and you can place everything in the same code behind class: data access, business logic, layout, etc. The controls take care of generating a great part of the HTML and JavaScript for you. With MVC there is no free lunch when it comes to data persistence between requests, you have to implement it yourself. As for event handling, that is at the core of MVC, in the form of controllers and action methods, you just don’t think of them as event handlers. In MVC you need to think more in HTTP terms, so action methods such as POST and GET are relevant to you, and may write actions to handle one or the other. Also of crucial importance is model binding: the way by which MVC converts your posted data into a .NET class. This is something that ASP.NET 4.5 Web Forms has introduced as well, but it is a cornerstone in MVC. MVC also has built-in validation of these .NET classes, which out of the box uses the Data Annotations API. You have full control of the generated HTML - except for that coming from the helper methods, usually small fragments - which requires a greater familiarity with the specifications. You normally rely much more on JavaScript APIs, they are even included in the Visual Studio template, that is because much less is done for you. Reuse It is difficult to accept a professional company/project that does not employ reuse. It can save a lot of time thus cutting costs significantly. Code reused in several projects matures as time goes by and helps developers learn from past experiences. ASP.NET Web Forms was built with reuse in mind, in the form of controls. Controls encapsulate functionality and are generally portable from project to project (with the notable exception of web user controls, those with an associated .ASCX markup file). ASP.NET has dozens of controls and it is very easy to develop new ones, so I believe this is a great advantage. A control can inject JavaScript code and external references as well as generate HTML an CSS. MVC on the other hand does not use controls – it is possible to use them, with some view engines like ASPX, but it is just not advisable because it breaks the flow – where do Init, Load, PreRender, etc, fit? The most similar to controls is extension methods, or helpers. They serve the same purpose – generating HTML, CSS or JavaScript – and can be reused between different projects. What differentiates them from controls is that there is no inheritance and no context – an extension method is just a static method which doesn’t know where it is being called. You also have partial views, which you can reuse in the same project, but there is no inheritance as well. This, in my view, is a weakness of MVC. Architecture Both technologies are highly extensible. I have writtenstarted writing a series of posts on ASP.NET Web Forms extensibility and will probably write another series on MVC extensibility as well. A number of scenarios are covered in any of these models, and some extensibility points apply to both, because, of course both stand upon ASP.NET. With Web Forms, if you’re like me, you start by defining you master pages, pages and controls, with some helper classes to glue everything. You may as well throw in some JavaScript, but probably you’re main work will be with plain old .NET code. The controls you define have the chance to inject JavaScript code and references, through either the ScriptManager or the page’s ClientScript object, as well as generating HTML and CSS code. The master page and page model with code behind classes offer a number of “hooks” by which you can change the normal way of things, for example, in a page you can access any control on the master page, add script or stylesheet references to its head and even change the page’s title. Also, with Web Forms, you typically have URLs in the form “/SomePath/SomePage.aspx?SomeParameter=SomeValue”, which isn’t really SEO friendly, no to mention the HTML that some controls produce, far from standards, optimization and best practices. In MVC, you also normally start by defining the master page (or layout) and views, which are the visible parts, and then define controllers on separate files. These controllers do not know anything about the views, except the names and types of the parameters that will be passed to and from them. The controller will be responsible for the data access and business logic, eventually relying on additional classes for this purpose. On a controller you only receive parameters and return a result, which may be a request for the rendering of a view, a redirection to another URL or a JSON object, to name just a few. The controller class does not know anything about the web, so you can effectively reuse it in a non-web project. This separation and the lack of programmatic access to the UI elements, makes it very difficult to implement, for example, something like SharePoint with MVC. OK, I know about Orchard, but it isn’t really a general purpose development framework, but instead, a CMS that happens to use MVC. Not having controls render HTML for you gives you in turn much more control over it – it is your responsibility to create it, which you can either consider a blessing or a curse, in the later case, you probably shouldn’t be using MVC at all. Also MVC URLs tend to be much more SEO-oriented, if you design your controllers and actions properly. Testing In a well defined architecture, you should separate business logic, data access logic and presentation logic, because these are all different things and it might even be the need to switch one implementation for another: for example, you might design a system which includes a data access layer, a business logic layer and two presentation layers, one on top of ASP.NET and the other with WPF; and the data access layer might be implemented first using NHibernate and later on switched for Entity Framework Code First. These changes are not that rare, so care should be taken in designing the system to make them possible. Web Forms are difficult to test, because it relies on event handlers which are only fired in web contexts, when a form is submitted or a page is requested. You can call them with reflection, but you have to set up a number of mocking objects first, HttpContext.Current first coming to my mind. MVC, on the other hand, makes testing controllers a breeze, so much that it even includes a template option for generating boilerplate unit test classes up from start. A well designed – from the unit test point of view - controller will receive everything it needs to work as parameters to its action methods, so you can pass whatever values you need very easily. That doesn’t mean, of course, that everything can be tested: views, for instance, are difficult to test without actually accessing the site, but MVC offers the possibility to compile views at build time, so that, at least, you know you don’t have syntax errors beforehand. Myths Some popular but unfounded myths around MVC include: You cannot use controls in MVC: not true, actually, you can, at least with the Web Forms (ASPX) view engine; the declaration and usage is exactly the same as with Web Forms; You cannot specify a base class for a view: with the ASPX view engine you can use the Inherits Page directive, with this and all the others you can use the pageBaseType and userControlBaseType attributes of the <page> element; MVC shields you from doing “bad things” on your views: well, you can place any code on a code block, at least with the ASPX view engine (you may be starting to see a pattern here), even data access code; The model is the entity model, tied to an O/RM: the model is actually any class that you use to pass values to a view, including (but generally not recommended) an entity model; Unit tests come with no cost: unit tests generally don’t cover the UI, although there are frameworks just for that (see WatiN, for example); also, for some tests, you will have to mock or replace either the HttpContext.Current property or the HttpContextBase class yourself; Everything is testable: views aren’t, without accessing the site; MVC relies on HTML5/some_cool_new_javascript_framework: there is no relation whatsoever, MVC renders whatever you want it to render and does not require any framework to be present. The thing is, the subsequent releases of MVC happened in a time when Microsoft has become much more involved in standards, so the files and technologies included in the Visual Studio templates reflect this, and it just happens to work well with jQuery, for example. Conclusion Well, this is how I see it. Some folks may think that I am being too rude on MVC, probably because I don’t like it, but that’s not true: like I said, I do like MVC and I am starting my new projects with it. I just don’t want to go along with that those that say that MVC is much superior to Web Forms, in fact, some things you can do much more easily with Web Forms than with MVC. I will be more than happy to hear what you think on this!

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  • ANTS Memory Profiler 8 released!

    - by Ben Emmett
    I’m excited to say that we’ve just released ANTS Memory Profiler 8! The big news is support for profiling .NET’s usage of unmanaged memory. There are two main parts to this. Firstly you can see a breakdown of unmanaged memory usage by module. This lets you see at a high level where unmanaged memory is being used – for example in the image below, it’s being used by a PDF generation library. Separately, when looking at a list of .NET classes, you can see how much unmanaged memory those classes are responsible for holding on to. You can also see that information for individual instances of those classes. Some clues you might need this: You’re using system objects or 3rd party components which deal with unmanaged memory under the hood (this includes things like the GDI+ functions used for working with bitmaps) Your application still relies on some legacy Delphi / C++ / etc code from left over from the days before your company moved over to using .NET You’ve used a previous version of ANTS Memory Profiler, and have ever seen a pie chart that looks something like this: You’ll also notice that the startup process has been entirely redesigned, bringing it in line with ANTS Performance Profiler 8, which was released earlier in the year. This makes it faster to start profiling and to run repeat profiling sessions, lets you profile using any browser instead of Internet Explorer, and also provides a host of stability improvements, particularly when launching websites in IIS. Download the new version (there’s a free trial), and as always I’d love to know what you think – just email [email protected]. Cheers! Ben

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  • Indian school boy never misses a class for 14 years. Applies for Gunnies Records

    - by Gopinath
    If you ask the question “What is the most fun activity?” to school or college kids, most of the kids would say “bunking classes”. Many of us are grown up bunking classes in the name of stomachache, relatives marriage, high fever, rain or some other reason. Here is a wonder kid who is an exception of regular school kids. Mohammed Omar, a 17 year Indian school boy, never skipped his classes for the past 14 years. His attendance records shows 100% for all the 14 years of school he attended so far and it’s an unbelievable track record. Omar lives in Kanpur, a suburban in Uttar Pradesh with parents and a younger brother. He attended school even when the area where he lives was once flooded, had high temperature. When flooded and motor vehicles were not able to run on the streets he loaned a bicycle from neighbors. When he was on high temperature he just popped a tablet and headed towards the school.  Whatever may be the adverse situation, he just found a way to attend school instead of bunking. He recently applied for Guinness Book of World Records. The determination of the boy is incredible and inspiration to many young. I  wish to see this guy soon flashing on TV Channels with Guinness World Records certificates on his hands. Source: NDTV, creative common image: flickr/seeveeaar

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  • C#/.NET Little Wonders: Tuples and Tuple Factory Methods

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can really help improve your code by making it easier to write and maintain.  This week, we look at the System.Tuple class and the handy factory methods for creating a Tuple by inferring the types. What is a Tuple? The System.Tuple is a class that tends to inspire a reaction in one of two ways: love or hate.  Simply put, a Tuple is a data structure that holds a specific number of items of a specific type in a specific order.  That is, a Tuple<int, string, int> is a tuple that contains exactly three items: an int, followed by a string, followed by an int.  The sequence is important not only to distinguish between two members of the tuple with the same type, but also for comparisons between tuples.  Some people tend to love tuples because they give you a quick way to combine multiple values into one result.  This can be handy for returning more than one value from a method (without using out or ref parameters), or for creating a compound key to a Dictionary, or any other purpose you can think of.  They can be especially handy when passing a series of items into a call that only takes one object parameter, such as passing an argument to a thread's startup routine.  In these cases, you do not need to define a class, simply create a tuple containing the types you wish to return, and you are ready to go? On the other hand, there are some people who see tuples as a crutch in object-oriented design.  They may view the tuple as a very watered down class with very little inherent semantic meaning.  As an example, what if you saw this in a piece of code: 1: var x = new Tuple<int, int>(2, 5); What are the contents of this tuple?  If the tuple isn't named appropriately, and if the contents of each member are not self evident from the type this can be a confusing question.  The people who tend to be against tuples would rather you explicitly code a class to contain the values, such as: 1: public sealed class RetrySettings 2: { 3: public int TimeoutSeconds { get; set; } 4: public int MaxRetries { get; set; } 5: } Here, the meaning of each int in the class is much more clear, but it's a bit more work to create the class and can clutter a solution with extra classes. So, what's the correct way to go?  That's a tough call.  You will have people who will argue quite well for one or the other.  For me, I consider the Tuple to be a tool to make it easy to collect values together easily.  There are times when I just need to combine items for a key or a result, in which case the tuple is short lived and so the meaning isn't easily lost and I feel this is a good compromise.  If the scope of the collection of items, though, is more application-wide I tend to favor creating a full class. Finally, it should be noted that tuples are immutable.  That means they are assigned a value at construction, and that value cannot be changed.  Now, of course if the tuple contains an item of a reference type, this means that the reference is immutable and not the item referred to. Tuples from 1 to N Tuples come in all sizes, you can have as few as one element in your tuple, or as many as you like.  However, since C# generics can't have an infinite generic type parameter list, any items after 7 have to be collapsed into another tuple, as we'll show shortly. So when you declare your tuple from sizes 1 (a 1-tuple or singleton) to 7 (a 7-tuple or septuple), simply include the appropriate number of type arguments: 1: // a singleton tuple of integer 2: Tuple<int> x; 3:  4: // or more 5: Tuple<int, double> y; 6:  7: // up to seven 8: Tuple<int, double, char, double, int, string, uint> z; Anything eight and above, and we have to nest tuples inside of tuples.  The last element of the 8-tuple is the generic type parameter Rest, this is special in that the Tuple checks to make sure at runtime that the type is a Tuple.  This means that a simple 8-tuple must nest a singleton tuple (one of the good uses for a singleton tuple, by the way) for the Rest property. 1: // an 8-tuple 2: Tuple<int, int, int, int, int, double, char, Tuple<string>> t8; 3:  4: // an 9-tuple 5: Tuple<int, int, int, int, double, int, char, Tuple<string, DateTime>> t9; 6:  7: // a 16-tuple 8: Tuple<int, int, int, int, int, int, int, Tuple<int, int, int, int, int, int, int, Tuple<int,int>>> t14; Notice that on the 14-tuple we had to have a nested tuple in the nested tuple.  Since the tuple can only support up to seven items, and then a rest element, that means that if the nested tuple needs more than seven items you must nest in it as well.  Constructing tuples Constructing tuples is just as straightforward as declaring them.  That said, you have two distinct ways to do it.  The first is to construct the tuple explicitly yourself: 1: var t3 = new Tuple<int, string, double>(1, "Hello", 3.1415927); This creates a triple that has an int, string, and double and assigns the values 1, "Hello", and 3.1415927 respectively.  Make sure the order of the arguments supplied matches the order of the types!  Also notice that we can't half-assign a tuple or create a default tuple.  Tuples are immutable (you can't change the values once constructed), so thus you must provide all values at construction time. Another way to easily create tuples is to do it implicitly using the System.Tuple static class's Create() factory methods.  These methods (much like C++'s std::make_pair method) will infer the types from the method call so you don't have to type them in.  This can dramatically reduce the amount of typing required especially for complex tuples! 1: // this 4-tuple is typed Tuple<int, double, string, char> 2: var t4 = Tuple.Create(42, 3.1415927, "Love", 'X'); Notice how much easier it is to use the factory methods and infer the types?  This can cut down on typing quite a bit when constructing tuples.  The Create() factory method can construct from a 1-tuple (singleton) to an 8-tuple (octuple), which of course will be a octuple where the last item is a singleton as we described before in nested tuples. Accessing tuple members Accessing a tuple's members is simplicity itself… mostly.  The properties for accessing up to the first seven items are Item1, Item2, …, Item7.  If you have an octuple or beyond, the final property is Rest which will give you the nested tuple which you can then access in a similar matter.  Once again, keep in mind that these are read-only properties and cannot be changed. 1: // for septuples and below, use the Item properties 2: var t1 = Tuple.Create(42, 3.14); 3:  4: Console.WriteLine("First item is {0} and second is {1}", 5: t1.Item1, t1.Item2); 6:  7: // for octuples and above, use Rest to retrieve nested tuple 8: var t9 = new Tuple<int, int, int, int, int, int, int, 9: Tuple<int, int>>(1,2,3,4,5,6,7,Tuple.Create(8,9)); 10:  11: Console.WriteLine("The 8th item is {0}", t9.Rest.Item1); Tuples are IStructuralComparable and IStructuralEquatable Most of you know about IComparable and IEquatable, what you may not know is that there are two sister interfaces to these that were added in .NET 4.0 to help support tuples.  These IStructuralComparable and IStructuralEquatable make it easy to compare two tuples for equality and ordering.  This is invaluable for sorting, and makes it easy to use tuples as a compound-key to a dictionary (one of my favorite uses)! Why is this so important?  Remember when we said that some folks think tuples are too generic and you should define a custom class?  This is all well and good, but if you want to design a custom class that can automatically order itself based on its members and build a hash code for itself based on its members, it is no longer a trivial task!  Thankfully the tuple does this all for you through the explicit implementations of these interfaces. For equality, two tuples are equal if all elements are equal between the two tuples, that is if t1.Item1 == t2.Item1 and t1.Item2 == t2.Item2, and so on.  For ordering, it's a little more complex in that it compares the two tuples one at a time starting at Item1, and sees which one has a smaller Item1.  If one has a smaller Item1, it is the smaller tuple.  However if both Item1 are the same, it compares Item2 and so on. For example: 1: var t1 = Tuple.Create(1, 3.14, "Hi"); 2: var t2 = Tuple.Create(1, 3.14, "Hi"); 3: var t3 = Tuple.Create(2, 2.72, "Bye"); 4:  5: // true, t1 == t2 because all items are == 6: Console.WriteLine("t1 == t2 : " + t1.Equals(t2)); 7:  8: // false, t1 != t2 because at least one item different 9: Console.WriteLine("t2 == t2 : " + t2.Equals(t3)); The actual implementation of IComparable, IEquatable, IStructuralComparable, and IStructuralEquatable is explicit, so if you want to invoke the methods defined there you'll have to manually cast to the appropriate interface: 1: // true because t1.Item1 < t3.Item1, if had been same would check Item2 and so on 2: Console.WriteLine("t1 < t3 : " + (((IComparable)t1).CompareTo(t3) < 0)); So, as I mentioned, the fact that tuples are automatically equatable and comparable (provided the types you use define equality and comparability as needed) means that we can use tuples for compound keys in hashing and ordering containers like Dictionary and SortedList: 1: var tupleDict = new Dictionary<Tuple<int, double, string>, string>(); 2:  3: tupleDict.Add(t1, "First tuple"); 4: tupleDict.Add(t2, "Second tuple"); 5: tupleDict.Add(t3, "Third tuple"); Because IEquatable defines GetHashCode(), and Tuple's IStructuralEquatable implementation creates this hash code by combining the hash codes of the members, this makes using the tuple as a complex key quite easy!  For example, let's say you are creating account charts for a financial application, and you want to cache those charts in a Dictionary based on the account number and the number of days of chart data (for example, a 1 day chart, 1 week chart, etc): 1: // the account number (string) and number of days (int) are key to get cached chart 2: var chartCache = new Dictionary<Tuple<string, int>, IChart>(); Summary The System.Tuple, like any tool, is best used where it will achieve a greater benefit.  I wouldn't advise overusing them, on objects with a large scope or it can become difficult to maintain.  However, when used properly in a well defined scope they can make your code cleaner and easier to maintain by removing the need for extraneous POCOs and custom property hashing and ordering. They are especially useful in defining compound keys to IDictionary implementations and for returning multiple values from methods, or passing multiple values to a single object parameter. Tweet Technorati Tags: C#,.NET,Tuple,Little Wonders

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  • Admob banner not getting remove from superview

    - by Anil gupta
    I am developing one 2d game using cocos2d framework, in this game i am using admob for advertising, in some classes not in all classes but admob banner is visible in every class and after some time game getting crash also. I am not getting how admob banner is comes in every class in fact i have not declare in Rootviewcontroller class. can any one suggest me how to integrate Admob in cocos2d game, i want Admob banner in particular classes not in every class, I am using latest google admob sdk, my code is below: Thanks in advance ` -(void)AdMob{ NSLog(@"ADMOB"); CGSize winSize = [[CCDirector sharedDirector]winSize]; // Create a view of the standard size at the bottom of the screen. if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad){ bannerView_ = [[GADBannerView alloc] initWithFrame:CGRectMake(size.width/2-364, size.height - GAD_SIZE_728x90.height, GAD_SIZE_728x90.width, GAD_SIZE_728x90.height)]; } else { // It's an iPhone bannerView_ = [[GADBannerView alloc] initWithFrame:CGRectMake(size.width/2-160, size.height - GAD_SIZE_320x50.height, GAD_SIZE_320x50.width, GAD_SIZE_320x50.height)]; } if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) { bannerView_.adUnitID =@"a15062384653c9e"; } else { bannerView_.adUnitID =@"a15062392a0aa0a"; } bannerView_.rootViewController = self; [[[CCDirector sharedDirector]openGLView]addSubview:bannerView_]; [bannerView_ loadRequest:[GADRequest request]]; GADRequest *request = [[GADRequest alloc] init]; request.testing = [NSArray arrayWithObjects: GAD_SIMULATOR_ID, nil]; // Simulator [bannerView_ loadRequest:request]; } //best practice for removing the barnnerView_ -(void)removeSubviews{ NSArray* subviews = [[CCDirector sharedDirector]openGLView].subviews; for (id SUB in subviews){ [(UIView*)SUB removeFromSuperview]; [SUB release]; } NSLog(@"remove from view"); } //this makes the refreshTimer count -(void)targetMethod:(NSTimer *)theTimer{ //INCREASE OF THE TIMER AND SECONDS elapsedTime++; seconds++; //INCREASE OF THE MINUTOS EACH 60 SECONDS if (seconds>=60) { seconds=0; minutes++; [self removeSubviews]; [self AdMob]; } NSLog(@"TIME: %02d:%02d", minutes, seconds); } `

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  • Novas video aulas gratuitas

    - by renatohaddad
    Olá Pessoal, Para você que estudou os meus treinamentos ou tem curiosidade em aprender um determinado tópico, acabei de colocar no meu site quatro novas Aulas Free com os seguintes tópicos: Alterar Web.Config em tempo de execução Veja como alterar os valores das chaves no web.config diretamente via código, permitindo ao administrador da aplicação alterar qualquer item no web.config sem precisar fazer download e upload do arquivo para efetuar as devidas alterações. Uso do DbSet no Entity Framework 4.1 Veja como instalar o EF 4.1, criar duas classes vinculadas, definir o contexto com o DbSet para que na execução do programa, o EF4.1 crie o banco de dados baseado nas classes. Uso de Tipos Complexos no Entity Framework 4 Sabia o que é e como aplicar um tipo complexo no Entity Framework 4. Desta forma você conseguirá criar propriedades complexas para otimizar a estrutura das classes, assim como aprender como que o tipo complexo é gerado no banco de dados sql server. Relacionamento muitos para muitos no Entity Framework 4 Aprenda como o Entity Framework 4 trabalha com um relacionamento muitos para muitos, desde a definição no ORM no EDMX, definir o tipo de associação, como incluir e ler dados das tabelas geradas no banco de dados do sql server. Deixe o "indiano" trabalhar com o compilador para nos ajudar, com certeza ele não irá errar nas tarefas. Bons estudos e fique à vontade para me dar feedbacks. Abração! Renato Haddad

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  • SOLID Thoughts

    - by GeekAgilistMercenary
    SOLID came up again in discussion.  What is SOLID?  Well, glad you asked, because I am going to elaborate on the SOLID Principles a bit. Initial Concept S Single Responsibility Principle O Open/Closed Principle L Liskov Substitution Principle I Interface Segregation Principle D Dependency Inversion/Injection Principle The Single Responsibility Principle (SRP) is stated that every object should have a single responsibility and should be entirely encapsulated by the class.  This helps keep cohesion.  Here is a short example, starting with a basic class. public class Car { decimal Gas; int Doors; int Speed; decimal RampJumpSpeed; } Now I will refactor a little bit to make it a bit more SRP friendly. public class Car { decimal Gas; int Speed; }   public class DuneBuggy : Car { decimal RampJumpSpeed; }   public class EconomyCar : Car { int Doors; } What we end up with, instead of one class, is an abstract class and two classes that have their respective methods or properties to keep the responsibilities were they need to be. The Open Closed Principle (OCP) is one of my favorites, which states simply, that you should be able to extend a classes behavior without modifying it.  There are a couple of ways one can extend a class, by inheritance, composition, or by proxy implementation.  The Liskov Substitution Principle (LSP) states that a derived class must be substitutable for their base classes. The Dependency Inversion Principle (DIP) states that one should depend on abstractions and not on concrete implementations. Finally, the Interface Segregation Principle (ISP) states that fine grain interfaces should be client specific. So hope that helps with kicking off a basic understanding of SOLID Principles.  I will be following this entry up with some new bits in the near future related to good software design and practice. Original post.

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  • All New Oracle Linux Curriculum Now Available

    - by Antoinette O'Sullivan
    Develop your system administration skills with the all new Oracle Linux System Administration Curriculum. This curriculum includes key courses which will help you with any version of Linux: Unix and Linux Essentials: This 3 day course helps those new to Oracle Linux with the basic skills they need to interact comfortably and confidently with the operating system. Oracle Linux System Administration: This 5 day course teaches those who are comfortable with the basic skills how to: Install Oracle Linux Gain an understanding of the benefits of Oracle's Unbreakable Enterprise Kernel (UEK) Configure the kernel, install packages, and update the kernel of a running system Configure users and rights, create and manage file systems, configure networking, and manage system security Properly prepare a Linux environment for installation of Oracle Database. Both these hands-on instructor-led courses are available as: Live-Virtual Delivery: You can attend these classes from your desk, no travel necessary. In-Class Delivery: You can travel to a classroom to attend these classes across the world. Some events already on the schedule shown below.  Location  Date  Delivery Language  Unix and Linux Essentials      Johannesburg, South Africa  8 October 2012  English  Woodmead, South Africa  15 July 2013  English  Denver, Colorado, US  23 January 2013  English  Jakarta, Indonesia  13 November 2012  English  Singapore  22 October 2012  English  Sydney, Australia  4 February 2013  English  Brisbane, Australia  29 April 2013  English  Melbourne, Australia  29 January 2013  English  Oracle Linux System Administration      Gaborone, Botswana  22 April 2013  English  Vilvoorde, Belgium  15 October 2012  English  Melbourne, Australia  26 November 2012  English For more information on these classes or to express interest in additional events, go to http://oracle.com/education/linux  

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  • CodePlex Daily Summary for Tuesday, June 05, 2012

    CodePlex Daily Summary for Tuesday, June 05, 2012Popular ReleasesApplication Architecture Guidelines: Application Architecture Guidelines 3.0.7: 3.0.7Jolt Environment: Jolt v2 Stable: Many new features. Follow development here for more information: http://www.rune-server.org/runescape-development/rs-503-client-server/projects/298763-jolt-environment-v2.html Setup instructions in downloadtedplay: tedplay 1.0: First public release of the Commodore 264 family (C16, plus/4) music player based on the SDL version of YAPE http://yape.homeserver.hu.SharePoint Euro 2012 - UEFA European Football Predictor: havivi.euro2012.wsp (1.5): New fetures:Multilingual Support Max users property in Standings Web Part Games time zone change (UTC +1) bug fix - Version 1.4 locking problem http://euro2012.codeplex.com/discussions/358262 bug fix - Field Title not found (v.1.3) German SP http://euro2012.codeplex.com/discussions/358189#post844228 Bug fix - Access is denied.for users with contribute rights Bug fix - Installing on non-English version of SharePoint Bug fix - Title Rules Installing SharePoint Euro 2012 PredictorSharePoint E...xNet: xNet 2.1.1: Release xNet 2.1.1Command Line Parser Library: 1.9.2.4 stable: This is the first stable of 1.9.* branch. Added tests for HelpText::AutoBuild. Fixed minor formatting error in HelpText::DefaultParsingErrorsHandler.myManga: myManga v1.0.0.4: ChangeLogUpdating from Previous Version: Extract contents of Release - myManga v1.0.0.4.zip to previous version's folder. Replaces: myManga.exe BakaBox.dll CoreMangaClasses.dll Manga.dll Plugins/MangaReader.manga.dll Plugins/MangaFox.manga.dll Plugins/MangaHere.manga.dll Plugins/MangaPanda.manga.dllMVVM Light Toolkit: V4RC (binaries only) including Windows 8 RP: This package contains all the latest DLLs for MVVM Light V4 RC. It includes the DLLs for Windows 8 Release Preview. An updated Nuget package is also available at http://nuget.org/packages/MvvmLightLibsPreviewExtAspNet: ExtAspNet v3.1.7: +2012-06-03 v3.1.7 -?????????BUG，??????RadioButtonList?，AJAX????????BUG（swtseaman、????）。 +?Grid?BoundField、HyperLinkField、LinkButtonField、WindowField??HtmlEncode?HtmlEncodeFormatString（TiDi）。 -HtmlEncode?HtmlEncodeFormatString??????true，??????HTML????????。 -??????Asp.Net??GridView?BoundField?????????。 -http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.boundfield.htmlencode -?Grid?HyperLinkField、WindowField??UrlEncode??，????URL??（???true）。 -?????????????，?????????????...Ela, functional language: Ela Platform 2012.3: 2012.3 is a stabilization release. It contains several improvements to Ela, std lib and Elide. Ela changes Fix:Op code 'Show' didn't work correctly when a format string was a thunk. Fix:Flipping a function wrapped in a thunk caused VM to crush. Fix:A bug fixed in concatenation of a thunk and a lazy list. Fix:Concatenation of a lazy list and a strict list could cause stack overflow in a case of recursive thunks. Fix:A bug fixed in applying 'show' to a result of a lazy and strict list...Cross Site Treeview - For MOSS 2007: Cross Site Treeview-Beta - WSP Solution: Cross Site Treeview-Beta - WSP SolutionLiveChat Starter Kit: LCSK v1.5.2: New features: Visitor location (City - Country) from geo-location Pass configuration via javascript for the chat box New visitor identification (no more using the IP address as visitor identification) To update from 1.5.1 Run the /src/1.5.2-sql-updates.txt SQL script to update your database tables. If you have it installed via NuGet, simply update your package and the file will be included so you can run the update script. New installation The easiest way to add LCSK to your app is by...Kendo UI ASP.NET Sample Applications: Sample Applications (2012-06-01): Sample application(s) demonstrating the use of Kendo UI in ASP.NET applications.Better Explorer: Better Explorer Beta 1: Finally, the first Beta is here! There were a lot of changes, including: Translations into 10 different languages (the translations are not complete and will be updated soon) Conditional Select new tools for managing archives Folder Tools tab new search bar and Search Tab new image editing tools update function many bug fixes, stability fixes, and memory leak fixes other new features as well! Please check it out and if there are any problems, let us know. :) Also, do not forge...Player Framework by Microsoft: Player Framework for Windows 8 Metro (Preview 3): Player Framework for HTML/JavaScript and XAML/C# Metro Style Applications. Additional DownloadsIIS Smooth Streaming Client SDK for Windows 8 Microsoft PlayReady Client SDK for Metro Style Apps Release notes:Support for Windows 8 Release Preview (released 5/31/12) Advertising support (VAST, MAST, VPAID, & clips) Miscellaneous improvements and bug fixesMicrosoft Ajax Minifier: Microsoft Ajax Minifier 4.54: Fix for issue #18161: pretty-printing CSS @media rule throws an exception due to mismatched Indent/Unindent pair.Silverlight Toolkit: Silverlight 5 Toolkit Source - May 2012: Source code for December 2011 Silverlight 5 Toolkit release.Windows 8 Metro RSS Reader: RSS Reader release 6: Changed background and foreground colors Used VariableSizeGrid layout to wrap blog posts with images Sort items with Images first, text-only last Enabled Caching to improve navigation between framesJson.NET: Json.NET 4.5 Release 6: New feature - Added IgnoreDataMemberAttribute support New feature - Added GetResolvedPropertyName to DefaultContractResolver New feature - Added CheckAdditionalContent to JsonSerializer Change - Metro build now always uses late bound reflection Change - JsonTextReader no longer returns no content after consecutive underlying content read failures Fix - Fixed bad JSON in an array with error handling creating an infinite loop Fix - Fixed deserializing objects with a non-default cons...DotNetNuke® Community Edition CMS: 06.02.00: Major Highlights Fixed issue in the Site Settings when single quotes were being treated as escape characters Fixed issue loading the Mobile Premium Data after upgrading from CE to PE Fixed errors logged when updating folder provider settings Fixed the order of the mobile device capabilities in the Site Redirection Management UI The User Profile page was completely rebuilt. We needed User Profiles to have multiple child pages. This would allow for the most flexibility by still f...New ProjectsDish: ????? ???????? ??? ??.DRESSCOLLECTION: THIS IS A MVC APPLICAITON WHICH HELPS IN CREATING RANGE OF CLOTH AND DRESS COLLECTION TO CHOOSE AND BUY.FlowTasks: FlowTasks is a framework to develop human and business workflowGroup3.ERP.Roleadministration: Software zum generieren von RollendefinitionenHierarchical Pages Orchard Module: Creates a Hierarchical Page content type that does everything the built-in Page type does, but items can also contain other pages (and thus are containable by other pages too).hot24.vn: is first my project, it very cu chuoi.Household Manager: fcsdvsdvsdcdLabView interface for windows HPC: This project is a prototype library that attempts to integrate in the same enviroment the Data Acquisition and the Data Analysis systems. The library is a collection of LabVIEW Virtual Instruments that permts the job submission to a Windows HPC cluster. Jobs results can be easaly collected in order to perform actions via the DAQ control. Full documentation and examples are included.markgroves.us: Hello this is the blog template for http://markgroves.us. MostrarDireccion: Muestra la Direccion donde Reside cada personaMSPTH2012: This project is for MSPTH2012. Pattern Rolling File Appender for log4net: Appender for log4net that is combination of PatternFileAppender and RollingFileAppenderPowershell By Example: The vision of Powershell By Example is to give those interested in Powershell the chance to learn Powershell scripting by example with the goal of empowering them to use Powershell to maintain their own Windows environments. Practica Cuarto A: proyecto bakanProvidence: Providence is an application meant to capture audio, video, and screen-shots for various purposes.Proyecto T2: Tarea 2 - aprendiendo a utilizar la herramientaServer Config Tools: ??? ?????? IIS ?????SharePoint Scheduling Assistant: Scheduling assistant built for schools and universities. Works with out-of-the-box list and involves no custom workflows.Steam Group Players: This tool is meant to allow access to Steam community groups with the ability to sort group members according to hours spent playing specific games (as well as overall play time). The reason for starting this project was to allow a "player of the week"-selection that is slightly more complex than picking one by random or just by total hours played (recently).t2belenlm4c: Ana Belen LandaTaskLogger: Handy little pop-up that allows you to track time spent on project tasks. Can be used to generate timesheets.TechnicBlog: ????TPL DataFlow Debugger Visualizer: Graphic debugger visualizer to TPL DataFlow networks enable to see live state of blocks and relations Compatible with VS 2012 RC VsDoc2JsDoc: The goal of this project is to convert VSDoc JavaScript comments of JayData classes to JSDoc comment format. Using this tool you can generate the API reference of your JayData components and keep your JavaScript documentation up-to-date.WorkOutTimer: WorkOutTimer This little tool provides an easy to use timer for your workouts, trainings, and more... It has two time period, one for working, and one to be cool! By default work time is set to 2 minutes, cool time is set to 1minute (Kick boxing settings), but you can set up each period time as you want. You can hang up, restart, or reset time. It offers a high visibility timer. It also counts rounds. So have great workout! If you use it and you think it’s cool for y...XLIFF Editor: This is an attempt at making an open source XLIFF editor for Windows. I am using the Open Language Tools Editor as the primary source for the ideas of the XLIFF Editor. I am new to C# so this is is for me an ambitious learning and hopefull succesfull project. Any help in positive criticism will be looked at gratefully. xNet: xNet - a class library for .NET Framework, which includes: - Classes for work with proxy servers: HTTP, Socks4 (and), Socks5. - Classes for work with HTTP 1.0/1.1 protocol: keep-alive, gzip, deflate, chunked, SSL, proxies and more. - Classes for work with multithreading: _a multithreaded bypassing the collection, asynchronous events and more_. - Classes helpers that extend standard classes .NET Framework: FileHelper, DirectoryHelper, StringHelper, XmlHelper, BitHelper and others.?????? «??????????? ??????»: ??????????? ??????????: description

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  • How to build MVC Views that work with polymorphic domain model design?

    - by Johann de Swardt
    This is more of a "how would you do it" type of question. The application I'm working on is an ASP.NET MVC4 app using Razor syntax. I've got a nice domain model which has a few polymorphic classes, awesome to work with in the code, but I have a few questions regarding the MVC front-end. Views are easy to build for normal classes, but when it comes to the polymorphic ones I'm stuck on deciding how to implement them. The one (ugly) option is to build a page which handles the base type (eg. IContract) and has a bunch of if statements to check if we passed in a IServiceContract or ISupplyContract instance. Not pretty and very nasty to maintain. The other option is to build a view for each of these IContract child classes, breaking DRY principles completely. Don't like doing this for obvious reasons. Another option (also not great) is to split the view into chunks with partials and build partial views for each of the child types that are loaded into the main view for the base type, then deciding to show or hide the partial in a single if statement in the partial. Also messy. I've also been thinking about building a master page with sections for the fields that only occur in subclasses and to build views for each subclass referencing the master page. This looks like the least problematic solution? It will allow for fairly simple maintenance and it doesn't involve code duplication. What are your thoughts? Am I missing something obvious that will make our lives easier? Suggestions?

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  • Single Responsibility Principle - How Can I Avoid Code Fragmentation?

    - by Dean Chalk
    I'm working on a team where the team leader is a virulent advocate of SOLID development principles. However, he lacks a lot of experience in getting complex software out of the door. We have a situation where he has applied SRP to what was already quite a complex code base, which has now become very highly fragmented and difficult to understand and debug. We now have a problem not only with code fragmentation, but also encapsulation, as methods within a class that may have been private or protected have been judged to represent a 'reason to change' and have been extracted to public or internal classes and interfaces which is not in keeping with the encapsulation goals of the application. We have some class constructors which take over 20 interface parameters, so our IoC registration and resolution is becoming a monster in its own right. I want to know if there is any 'refactor away from SRP' approach we could use to help fix some of these issues. I have read that it doesn't violate SOLID if I create a number of empty courser-grained classes that 'wrap' a number of closely related classes to provide a single-point of access to the sum of their functionality (i.e. mimicking a less overly SRP'd class implementation). Apart from that, I cannot think of a solution which will allow us to pragmatically continue with our development efforts, while keeping everyone happy. Any suggestions ?

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  • Where should I put bindings for dependency injection?

    - by Mike G
    I'm new to dependency injection and though I've really liked it so far, I'm not sure where bindings should go. I'm using Guice in Java, so some of what I say might be specific to just Guice. As I see it, there's two options: Accompanying the class(s) its needed for. Then, just write install(OtherClassModule.class) in whatever other modules want to be able to use said class. As I see it, the advantage of this is that classes that want to use it (or manage classes that want to use it) don't need to know any of the implementation detail. The issue I see is that what if two classes want to use two different versions of the same class? There's a lot of customization possible because of DI and this seems to restrict it a lot. Implemented in the module of the class(s) its needed for. It's the flip of what I said above. Now you have customization, but not encapsulation. Is there a third option? Am I misunderstanding something obvious? What's the best practice?

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  • How to avoid big and clumpsy UITableViewController on iOS?

    - by Johan Karlsson
    I have a problem when implementing the MVC-pattern on iOS. I have searched the Internet but seems not to find any nice solution to this problem. Many UITableViewController implementations seems to be rather big. Most example I have seen lets the UITableViewController implement UITableViewDelegate and UITableViewDataSource. These implementations are a big reason why UITableViewControlleris getting big. One solution would be to create separate classes that implements UITableViewDelegate and UITableViewDataSource. Of course these classes would have to have a reference to the UITableViewController. Are there any drawbacks using this solution? In general I think you should delegate the functionality to other "Helper" classes or similar, using the delegate pattern. Are there any well established ways of solving this problem? I do not want the model to contain to much functionality, nor the view. A believe that the logic should really be in the controller class, since this is one of the cornerstones of the MVC-pattern. But the big question is; How should you divide the controller of a MVC-implementation into smaller manageable pieces? (Applies to MVC in iOS in this case) There might be a general pattern for solving this, although I am specifically looking for a solution for iOS. Please give an example of a good pattern for solving this issue. Also an argument why this solution is awesome.

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  • With which class to start Test Driven Development of card game application? And what would be the next 5 to 7 tests?

    - by Maxis
    I have started to write card game applications. Some model classes: CardSuit, CardValue, Card Deck, IDeckCreator, RegularDeckCreator, DoubleDeckCreator Board Hand and some game classes: Turn, TurnHandler IPlayer, ComputerPlayer, HumanPlayer IAttackStrategy, SimpleAttachStrategy, IDefenceStrategy, SimpleDefenceStrategy GameData, Game are already written. My idea is to create engine, where two computer players could play game and then later I could add UI part. Already for some time I'm reading about Test Driven Development (TDD) and I have idea to start writing application from scratch, as currently I have tendency to write not needed code, which seems usable in future. Also code doesn't have any tests and it is hard to add them now. Seems that TDD could improve all these issue - minimum of needed code, good test coverage and also could help to come to right application design. But I have one issue - I can't decide from where to start TDD? Should I start from bottom - Card related classes or somewhere on top - Game, TurnHandler, ... ? With which class you would start? And what would be the next 5 to 7 tests? (use the card game you know the best) I would like to start TDD with your help and then continue on my own!

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  • How to avoid big and clumsy UITableViewController on iOS?

    - by Johan Karlsson
    I have a problem when implementing the MVC-pattern on iOS. I have searched the Internet but seems not to find any nice solution to this problem. Many UITableViewController implementations seems to be rather big. Most examples I have seen lets the UITableViewController implement <UITableViewDelegate> and <UITableViewDataSource>. These implementations are a big reason why UITableViewControlleris getting big. One solution would be to create separate classes that implements <UITableViewDelegate> and <UITableViewDataSource>. Of course these classes would have to have a reference to the UITableViewController. Are there any drawbacks using this solution? In general I think you should delegate the functionality to other "Helper" classes or similar, using the delegate pattern. Are there any well established ways of solving this problem? I do not want the model to contain too much functionality, nor the view. I believe that the logic should really be in the controller class, since this is one of the cornerstones of the MVC-pattern. But the big question is: How should you divide the controller of a MVC-implementation into smaller manageable pieces? (Applies to MVC in iOS in this case) There might be a general pattern for solving this, although I am specifically looking for a solution for iOS. Please give an example of a good pattern for solving this issue. Please provide an argument why your solution is awesome.

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  • Is defining every method/state per object in a series of UML diagrams representative of MDA in general?

    - by Max
    I am currently working on a project where we use a framework that combines code generation and ORM together with UML to develop software. Methods are added to UML classes and are generated into partial classes where "stuff happens". For example, an UML class "Content" could have the method DeleteFromFileSystem(void). Which could be implemented like this: public partial class Content { public void DeleteFromFileSystem() { File.Delete(...); } } All methods are designed like this. Everything happens in these gargantuan logic-bomb domain classes. Is this how MDA or DDD or similar usually is done? For now my impression of MDA/DDD (which this has been called by higherups) is that it severely stunts my productivity (everything must be done The Way) and that it hinders maintenance work since all logic are roped, entrenched, interspersed into the mentioned gargantuan bombs. Please refrain from interpreting this as a rant - I am merely curious if this is typical MDA or some sort of extreme MDA UPDATE Concerning the example above, in my opinion Content shouldn't handle deleting itself as such. What if we change from local storage to Amazon S3, in that case we would have to reimplement this functionality scattered over multiple places instead of one single interface which we can provide a second implementation for.

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  • Using unordered_multimap as entity and component storage

    - by natebot13
    The Setup I've made a few games (more like animations) using the Object Oriented method with base classes for objects that extend them, and objects that extend those, and found I couldn't wrap my head around expanding that system to larger game ideas. So I did some research and discovered the Entity-Component system of designing games. I really like the idea, and thoroughly understood the usefulness of it after reading Byte54's perfect answer here: Role of systems in entity systems architecture. With that said, I have decided to create my current game idea using the described Entity-Component system. Having basic knowledge of C++, and SFML, I would like to implement the backbone of this entity component system using an unordered_multimap without classes for the entities themselves. Here's the idea: An unordered_mulitmap stores entity IDs as the lookup term, while the value is an inherited Component object. Examlpe: ____________________________ |ID |Component | ---------------------------- |0 |Movable | |0 |Accelable | |0 |Renderable | |1 |Movable | |1 |Renderable | |2 |Renderable | ---------------------------- So, according to this map of objects, the entity with ID 0 has three components: Movable, Accelable, and Renderable. These component objects store the entity specific data, such as the location, the acceleration, and render flags. The entity is simply and ID, with the components attached to that ID describing its attributes. Problem I want to store the component objects within the map, allowing the map have full ownership of the components. The problem I'm having, is I don't quite understand enough about pointers, shared pointers, and references in order to get that set up. How can I go about initializing these components, with their various member variables, within the unordered_multimap? Can the base component class take on the member variables of its child classes, when defining the map as unordered_multimap<int, component>? Requirements I need a system to be able to grab an entity, with all of its' attached components, and access members from the components in order to do the necessary calculations and reassignments for position, velocity, etc. Need a clarification? Post a comment with your concerns and I will gladly edit or comment back! Thanks in advance! natebot13

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  • Vector with Constant-Time Remove - still a Vector?

    - by Darrel Hoffman
    One of the drawbacks of most common implementations of the Vector class (or ArrayList, etc. Basically any array-backed expandable list class) is that their remove() operation generally operates in linear time - if you remove an element, you must shift all elements after it one space back to keep the data contiguous. But what if you're using a Vector just to be a list-of-things, where the order of the things is irrelevant? In this case removal can be accomplished in a few simple steps: Swap element to be removed with the last element in the array Reduce size field by 1. (No need to re-allocate the array, as the deleted item is now beyond the size field and thus not "in" the list any more. The next add() will just overwrite it.) (optional) Delete last element to free up its memory. (Not needed in garbage-collected languages.) This is clearly now a constant-time operation, since only performs a single swap regardless of size. The downside is of course that it changes the order of the data, but if you don't care about the order, that's not a problem. Could this still be called a Vector? Or is it something different? It has some things in common with "Set" classes in that the order is irrelevant, but unlike a Set it can store duplicate values. (Also most Set classes I know of are backed by a tree or hash map rather than an array.) It also bears some similarity to Heap classes, although without the log(N) percolate steps since we don't care about the order.

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  • whats the name of this pattern?

    - by Wes
    I see this a lot in frameworks. You have a master class which other classes register with. The master class then decides which of the registered classes to delegate the request to. An example based passed in class may be something this. public interface Processor { public boolean canHandle(Object objectToHandle); public void handle(Object objectToHandle); } public class EvenNumberProcessor extends Processor { public boolean canHandle(Object objectToHandle) { if (!isNumeric(objectToHandle)){ return false } return isEven(objectToHandle); } public void handle(objectToHandle) { //Optionally call canHandleAgain to ensure the calling class is fufilling its contract doSomething(); } } public class OddNumberProcessor extends Processor { public boolean canHandle(Object objectToHandle) { if (!isNumeric(objectToHandle)){ return false } return isOdd(objectToHandle); } public void handle(objectToHandle) { //Optionally call canHandleAgain to ensure the calling class is fufilling its contract doSomething(); } } //Can optionally implement processor interface public class processorDelegator { private List processors; public void addProcessor(Processor processor) { processors.add(processor); } public void process(Object objectToProcess) { //Lookup relevant processor either by keeping a list of what they can process //Or query each one to see if it can process the object. chosenProcessor=chooseProcessor(objectToProcess); chosenProcessor.handle(objectToProcess); } } Note there are a few variations I see on this. In one variation the sub classes provide a list of things they can process which the ProcessorDelegator understands. The other variation which is listed above in fake code is where each is queried in turn. This is similar to chain of command but I don't think its the same as chain of command means that the processor needs to pass to other processors. The other variation is where the ProcessorDelegator itself implements the interface which means you can get trees of ProcessorDelegators which specialise further. In the above example you could have a numeric processor delegator which delegates to an even/odd processor and a string processordelegator which delegates to different strings. My question is does this pattern have a name.

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  • Auto-hydrate your objects with ADO.NET

    - by Jake Rutherford
    Recently while writing the monotonous code for pulling data out of a DataReader to hydrate some objects in an application I suddenly wondered "is this really necessary?" You've probably asked yourself the same question, and many of you have: - Used a code generator - Used a ORM such as Entity Framework - Wrote the code anyway because you like busy work     In most of the cases I've dealt with when making a call to a stored procedure the column names match up with the properties of the object I am hydrating. Sure that isn't always the case, but most of the time it's 1 to 1 mapping.  Given that fact I whipped up the following method of hydrating my objects without having write all of the code. First I'll show the code, and then explain what it is doing.      /// <summary>     /// Abstract base class for all Shared objects.     /// </summary>     /// <typeparam name="T"></typeparam>     [Serializable, DataContract(Name = "{0}SharedBase")]     public abstract class SharedBase<T> where T : SharedBase<T>     {         private static List<PropertyInfo> cachedProperties;         /// <summary>         /// Hydrates derived class with values from record.         /// </summary>         /// <param name="dataRecord"></param>         /// <param name="instance"></param>         public static void Hydrate(IDataRecord dataRecord, T instance)         {             var instanceType = instance.GetType();                         //Caching properties to avoid repeated calls to GetProperties.             //Noticable performance gains when processing same types repeatedly.             if (cachedProperties == null)             {                 cachedProperties = instanceType.GetProperties().ToList();             }                         foreach (var property in cachedProperties)             {                 if (!dataRecord.ColumnExists(property.Name)) continue;                 var ordinal = dataRecord.GetOrdinal(property.Name);                 var isNullable = property.PropertyType.IsGenericType &&                                  property.PropertyType.GetGenericTypeDefinition() == typeof (Nullable<>);                 var isNull = dataRecord.IsDBNull(ordinal);                 var propertyType = property.PropertyType;                 if (isNullable)                 {                     if (!string.IsNullOrEmpty(propertyType.FullName))                     {                         var nullableType = Type.GetType(propertyType.FullName);                         propertyType = nullableType != null ? nullableType.GetGenericArguments()[0] : propertyType;                     }                 }                 switch (Type.GetTypeCode(propertyType))                 {                     case TypeCode.Int32:                         property.SetValue(instance,                                           (isNullable && isNull) ? (int?) null : dataRecord.GetInt32(ordinal), null);                         break;                     case TypeCode.Double:                         property.SetValue(instance,                                           (isNullable && isNull) ? (double?) null : dataRecord.GetDouble(ordinal),                                           null);                         break;                     case TypeCode.Boolean:                         property.SetValue(instance,                                           (isNullable && isNull) ? (bool?) null : dataRecord.GetBoolean(ordinal),                                           null);                         break;                     case TypeCode.String:                         property.SetValue(instance, (isNullable && isNull) ? null : isNull ? null : dataRecord.GetString(ordinal),                                           null);                         break;                     case TypeCode.Int16:                         property.SetValue(instance,                                           (isNullable && isNull) ? (int?) null : dataRecord.GetInt16(ordinal), null);                         break;                     case TypeCode.DateTime:                         property.SetValue(instance,                                           (isNullable && isNull)                                               ? (DateTime?) null                                               : dataRecord.GetDateTime(ordinal), null);                         break;                 }             }         }     }   Here is a class which utilizes the above: [Serializable] [DataContract] public class foo : SharedBase<foo> {     [DataMember]     public int? ID { get; set; }     [DataMember]     public string Name { get; set; }     [DataMember]     public string Description { get; set; }     [DataMember]     public string Subject { get; set; }     [DataMember]     public string Body { get; set; }            public foo(IDataRecord record)     {         Hydrate(record, this);                }     public foo() {} }   Explanation: - Class foo inherits from SharedBase specifying itself as the type. (NOTE SharedBase is abstract here in the event we want to provide additional methods which could be overridden by the instance class) public class foo : SharedBase<foo> - One of the foo class constructors accepts a data record which then calls the Hydrate method on SharedBase passing in the record and itself. public foo(IDataRecord record) {      Hydrate(record, this); } - Hydrate method on SharedBase will use reflection on the object passed in to determine its properties. At the same time, it will effectively cache these properties to avoid repeated expensive reflection calls public static void Hydrate(IDataRecord dataRecord, T instance) {      var instanceType = instance.GetType();      //Caching properties to avoid repeated calls to GetProperties.      //Noticable performance gains when processing same types repeatedly.      if (cachedProperties == null)      {           cachedProperties = instanceType.GetProperties().ToList();      } . . . - Hydrate method on SharedBase will iterate each property on the object and determine if a column with matching name exists in data record foreach (var property in cachedProperties) {      if (!dataRecord.ColumnExists(property.Name)) continue;      var ordinal = dataRecord.GetOrdinal(property.Name); . . . NOTE: ColumnExists is an extension method I put on IDataRecord which I’ll include at the end of this post. - Hydrate method will determine if the property is nullable and whether the value in the corresponding column of the data record has a null value var isNullable = property.PropertyType.IsGenericType && property.PropertyType.GetGenericTypeDefinition() == typeof (Nullable<>); var isNull = dataRecord.IsDBNull(ordinal); var propertyType = property.PropertyType; . . .  - If Hydrate method determines the property is nullable it will determine the underlying type and set propertyType accordingly - Hydrate method will set the value of the property based upon the propertyType   That’s it!!!   The magic here is in a few places. First, you may have noticed the following: public abstract class SharedBase<T> where T : SharedBase<T> This says that SharedBase can be created with any type and that for each type it will have it’s own instance. This is important because of the static members within SharedBase. We want this behavior because we are caching the properties for each type. If we did not handle things in this way only 1 type could be cached at a time, or, we’d need to create a collection that allows us to cache the properties for each type = not very elegant.   Second, in the constructor for foo you may have noticed this (literally): public foo(IDataRecord record) {      Hydrate(record, this); } I wanted the code for auto-hydrating to be as simple as possible. At first I wasn’t quite sure how I could call Hydrate on SharedBase within an instance of the class and pass in the instance itself. Fortunately simply passing in “this” does the trick. I wasn’t sure it would work until I tried it out, and fortunately it did.   So, to actually use this feature when utilizing ADO.NET you’d do something like the following:        public List<foo> GetFoo(int? fooId)         {             List<foo> fooList;             const string uspName = "usp_GetFoo";             using (var conn = new SqlConnection(_dbConnection))             using (var cmd = new SqlCommand(uspName, conn))             {                 cmd.CommandType = CommandType.StoredProcedure;                 cmd.Parameters.Add(new SqlParameter("@FooID", SqlDbType.Int)                                        {Direction = ParameterDirection.Input, Value = fooId});                 conn.Open();                 using (var dr = cmd.ExecuteReader())                 {                     fooList= (from row in dr.Cast<DbDataRecord>()                                             select                                                 new foo(row)                                            ).ToList();                 }             }             return fooList;         }   Nice! Instead of having line after line manually assigning values from data record to an object you simply create a new instance and pass in the data record. Note that there are certainly instances where columns returned from stored procedure do not always match up with property names. In this scenario you can still use the above method and simply do your manual assignments afterward.

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  • How to structure my GUI agnostic project?

    - by Nezreli
    I have a project which loads from database a XML file which defines a form for some user. XML is transformed into a collection of objects whose classes derive from single parent. Something like Control - EditControl - TextBox Control - ContainterControl - Panel Those classes are responsible for creation of GUI controls for three different enviroments: WinForms, DevExpress XtraReports and WebForms. All three frameworks share mostly the same control tree and have a common single parent (Windows.Forms.Control, XrControl and WebControl). So, how to do it? Solution a) Control class has abstract methods Control CreateWinControl(); XrControl CreateXtraControl(); WebControl CreateWebControl(); This could work but the project has to reference all three frameworks and the classes are going to be fat with methods which would support all three implementations. Solution b) Each framework implementation is done in separate projects and have the exact class tree like the Core project. All three implementations are connected using a interface to the Core class. This seems clean but I'm having a hard time wrapping my head around it. Does anyone have a simpler solution or a suggestion how should I approach this task?

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  • Thematic map contd.

    - by jsharma
    The previous post (creating a thematic map) described the use of an advanced style (color ranged-bucket style). The bucket style definition object has an attribute ('classification') which specifies the data classification scheme to use. It's values can be one of {'equal', 'quantile', 'logarithmic', 'custom'}. We use logarithmic in the previous example. Here we'll describe how to use a custom algorithm for classification. Specifically the Jenks Natural Breaks algorithm. We'll use the Javascript implementation in geostats.js The sample code above needs a few changes which are listed below. Include the geostats.js file after or before including oraclemapsv2.js <script src="geostats.js"></script> Modify the bucket style definition to use custom classification Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}    bucketStyleDef = {       numClasses : colorSeries[colorName].classes,       classification: 'custom', //'logarithmic',  // use a logarithmic scale       algorithm: jenksFromGeostats,       styles: theStyles,       gradient:  useGradient? 'linear' : 'off'     }; The function, which implements the custom classification scheme, is specified as the algorithm attribute value. It must accept two input parameters, an array of OM.feature and the name of the feature attribute (e.g. TOTPOP) to use in the classification, and must return an array of buckets (i.e. an array of or OM.style.Bucket  or OM.style.RangedBucket in this case). However the algorithm also needs to know the number of classes (i.e. the number of buckets to create). So we use a global to pass that info in. (Note: This bug/oversight will be fixed and the custom algorithm will be passed 3 parameters: the features array, attribute name, and number of classes). So createBucketColorStyle() has the following changes Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} var numClasses ; function createBucketColorStyle( colorName, colorSeries, rangeName, useGradient) {    var theBucketStyle;    var bucketStyleDef;    var theStyles = [];    //var numClasses ; numClasses = colorSeries[colorName].classes; ... and the function jenksFromGeostats is defined as Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} function jenksFromGeostats(featureArray, columnName) {    var items = [] ; // array of attribute values to be classified    $.each(featureArray, function(i, feature) {         items.push(parseFloat(feature.getAttributeValue(columnName)));    });    // create the geostats object    var theSeries = new geostats(items);    // call getJenks which returns an array of bounds    var theClasses = theSeries.getJenks(numClasses);    if(theClasses)    {     theClasses[theClasses.length-1]=parseFloat(theClasses[theClasses.length-1])+1;    }    else    {     alert(' empty result from getJenks');    }    var theBuckets = [], aBucket=null ;    for(var k=0; k<numClasses; k++)    {             aBucket = new OM.style.RangedBucket(             {low:parseFloat(theClasses[k]),               high:parseFloat(theClasses[k+1])             });             theBuckets.push(aBucket);     }     return theBuckets; } A screenshot of the resulting map with 5 classes is shown below. It is also possible to simply create the buckets and supply them when defining the Bucket style instead of specifying the function (algorithm). In that case the bucket style definition object would be    bucketStyleDef = {      numClasses : colorSeries[colorName].classes,      classification: 'custom',        buckets: theBuckets, //since we are supplying all the buckets      styles: theStyles,      gradient:  useGradient? 'linear' : 'off'    };

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  • Any algorithm to dedicate a set of known resources to a set of known requirements (scheduling)

    - by Saeed Neamati
    I'm developing an application to help school principals in dedicating teachers to classes and courses over the hours of a week (scheduling). The scenario is roughly something like this: User enters the list of teachers and their free times into the system User enters the list of courses for this semester User enters the list of available classes into the system Well, up to here, there is no big deal. Just simple CRUD operations and nothing extraordinary. However, now what makes this system useful is that the application should automatically and based on an algorithm create the semester scheduling. I think you've got the main idea here. For example application should suggest that teacher A should go to class 1 for mathematics, and at the same time teacher B should go to class 2 for physics. This way all of the classes would be dedicated to lessons and teacher times won't overlap each other. Piece a cake for school principal. However, I can't find a good algorithm for this resource dedication. I mean it seems hard to me. Searching Google resulted in articles from different websites, but they are of no help and use to me. For example: http://en.wikipedia.org/wiki/Resource_allocation or http://en.wikipedia.org/wiki/Scheduling_(production_processes) Is there any algorithm out there, or any application or engine which can help me here? Does this requirements have a known name, like for example time scheduling engine? Any help would be appreciated.

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  • Android From Local DB (DAO) to Server sync (JSON) - Design issue

    - by Taiko
    I sync data between my local DB and a Server. I'm looking for the cleanest way to modelise all of this. I have a com.something.db package That contains a Data Helper and couple of DAO classes that represents objects stored in the db (I didn't write that part) com.something.db --public DataHelper --public Employee @DatabaseField e.g. "name" will be an actual column name in the DB -name @DatabaseField -salary etc... (all in all 50 fields) I have a com.something.sync package That contains all the implementation detail on how to send data to the server. It boils down to a ConnectionManager that is fed by different classes that implements a 'Request' interface com.something.sync --public interface ConnectionManager --package ConnectionManagerImpl --public interface Request --package LoginRequest --package GetEmployeesRequest My issue is, at some point in the sync process, I have to JSONise and de-JSONise my data (E.g. the Employee class). But I really don't feel like having the same Employee class be responsible for both his JSONisation and his actual representation inside the local database. It really doesn't feel right, because I carefully decoupled the rest, I am only stuck on this JSON thing. What should I do ? Should I write 3 Employee classes ? EmployeeDB @DatabaseField e.g. "name" will be an actual column name in the DB -name @DatabaseField -salary -etc... 50 fields EmployeeInterface -getName -getSalary -etc... 50 fields EmployeeJSON -JSON_KEY_NAME = "name" The JSON key happens to be the same as the table name, but it isn't requirement -name -JSON_KEY_SALARY = "salary" -salary -etc... 50 fields It feels like a lot of duplicates. Is there a common pattern I can use there ?

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  • How to do MVC the right way

    - by Ieyasu Sawada
    I've been doing MVC for a few months now using the CodeIgniter framework in PHP but I still don't know if I'm really doing things right. What I currently do is: Model - this is where I put database queries (select, insert, update, delete). Here's a sample from one of the models that I have: function register_user($user_login, $user_profile, $department, $role) { $department_id = $this->get_department_id($department); $role_id = $this->get_role_id($role); array_push($user_login, $department_id, $role_id); $this->db->query("INSERT INTO tbl_users SET username=?, hashed_password=?, salt=?, department_id=?, role_id=?", $user_login); $user_id = $this->db->insert_id(); array_push($user_profile, $user_id); $this->db->query(" INSERT INTO tbl_userprofile SET firstname=?, midname=?, lastname=?, user_id=? ", $user_profile); } Controller - talks to the model, calls up the methods in the model which queries the database, supplies the data which the views will display(success alerts, error alerts, data from database), inherits a parent controller which checks if user is logged in. Here's a sample: function create_user(){ $this->load->helper('encryption/Bcrypt'); $bcrypt = new Bcrypt(15); $user_data = array( 'username' => 'Username', 'firstname' => 'Firstname', 'middlename' => 'Middlename', 'lastname' => 'Lastname', 'password' => 'Password', 'department' => 'Department', 'role' => 'Role' ); foreach ($user_data as $key => $value) { $this->form_validation->set_rules($key, $value, 'required|trim'); } if ($this->form_validation->run() == FALSE) { $departments = $this->user_model->list_departments(); $it_roles = $this->user_model->list_roles(1); $tc_roles = $this->user_model->list_roles(2); $assessor_roles = $this->user_model->list_roles(3); $data['data'] = array('departments' => $departments, 'it_roles' => $it_roles, 'tc_roles' => $tc_roles, 'assessor_roles' => $assessor_roles); $data['content'] = 'admin/create_user'; parent::error_alert(); $this->load->view($this->_at, $data); } else { $username = $this->input->post('username'); $salt = $bcrypt->getSalt(); $hashed_password = $bcrypt->hash($this->input->post('password'), $salt); $fname = $this->input->post('firstname'); $mname = $this->input->post('middlename'); $lname = $this->input->post('lastname'); $department = $this->input->post('department'); $role = $this->input->post('role'); $user_login = array($username, $hashed_password, $salt); $user_profile = array($fname, $mname, $lname); $this->user_model->register_user($user_login, $user_profile, $department, $role); $data['content'] = 'admin/view_user'; parent::success_alert(4, 'User Sucessfully Registered!', 'You may now login using your account'); $data['data'] = array('username' => $username, 'fname' => $fname, 'mname' => $mname, 'lname' => $lname, 'department' => $department, 'role' => $role); $this->load->view($this->_at, $data); } } Views - this is where I put html, css, and JavaScript code (form validation code for the current form, looping through the data supplied by controller, a few if statements to hide and show things depending on the data supplied by the controller). <!--User registration form--> <form class="well min-form" method="post"> <div class="form-heading"> <h3>User Registration</h3> </div> <label for="username">Username</label> <input type="text" id="username" name="username" class="span3" autofocus> <label for="password">Password</label> <input type="password" id="password" name="password" class="span3"> <label for="firstname">First name</label> <input type="text" id="firstname" name="firstname" class="span3"> <label for="middlename">Middle name</label> <input type="text" id="middlename" name="middlename" class="span3"> <label for="lastname">Last name</label> <input type="text" id="lastname" name="lastname" class="span3"> <label for="department">Department</label> <input type="text" id="department" name="department" class="span3" list="list_departments"> <datalist id="list_departments"> <?php foreach ($data['departments'] as $row) { ?> <option data-id="<?php echo $row['department_id']; ?>" value="<?php echo $row['department']; ?>"><?php echo $row['department']; ?></option> <?php } ?> </datalist> <label for="role">Role</label> <input type="text" id="role" name="role" class="span3" list=""> <datalist id="list_it"> <?php foreach ($data['it_roles'] as $row) { ?> <option data-id="<?php echo $row['role_id']; ?>" value="<?php echo $row['role']; ?>"><?php echo $row['role']; ?></option> <?php } ?> </datalist> <datalist id="list_collection"> <?php foreach ($data['tc_roles'] as $row) { ?> <option data-id="<?php echo $row['role_id']; ?>" value="<?php echo $row['role']; ?>"><?php echo $row['role']; ?></option> <?php } ?> </datalist> <datalist id="list_assessor"> <?php foreach ($data['assessor_roles'] as $row) { ?> <option data-id="<?php echo $row['role_id']; ?>" value="<?php echo $row['role']; ?>"><?php echo $row['role']; ?></option> <?php } ?> </datalist> <p> <button type="submit" class="btn btn-success">Create User</button> </p> </form> <script> var departments = []; var roles = []; $('#list_departments option').each(function(i){ departments[i] = $(this).val(); }); $('#list_it option').each(function(i){ roles[roles.length + 1] = $(this).val(); }); $('#list_collection option').each(function(i){ roles[roles.length + 1] = $(this).val(); }); $('#list_assessor option').each(function(i){ roles[roles.length + 1] = $(this).val(); }); $('#department').blur(function(){ var department = $.trim($(this).val()); $('#role').attr('list', 'list_' + department); }); var password = new LiveValidation('password'); password.add(Validate.Presence); password.add(Validate.Length, {minimum: 10}); $('input[type=text]').each(function(i){ var field_id = $(this).attr('id'); var field = new LiveValidation(field_id); field.add(Validate.Presence); if(field_id == 'department'){ field.add(Validate.Inclusion, {within : departments}); } else if(field_id == 'role'){ field.add(Validate.Inclusion, {within : roles}) } }); </script> The codes above are actually code from the application that I'm currently working on. I'm working on it alone so I don't really have someone to review my code for me and point out the wrong things in it so I'm posting it here in hopes that someone could point out the wrong things that I've done in here. I'm also looking for some guidelines in writing MVC code like what are the things that should be and shouldn't be included in views, models and controllers. How else can I improve the current code that I have right now. I've written some really terrible code before(duplication of logic, etc.) that's why I want to improve my code so that I can easily maintain it in the future. Thanks!

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