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  • How to integrate KVC in MVC?

    - by Paperflyer
    So I have an MVC-application in Cocoa. There are some custom views, a controller and a model. Of course, the views need to know some stuff, so they get their data from the controller. However, they do not use accessors in the controller, they use KVC with a keypath that calls right through to the model: // In view.m time = [timeSource valueForKeyPath:@"theModel.currentTime"]; // timeSource is a pseudo-delegate of the view that holds the controller This simplifies things a great deal and technically, the views still don't know the model in person (that is, in pointer). But of course, they access it directly. Is that a usual (or at least sensible) usage of KVC and MVC? Or how would you implement this kind of communication?

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  • Subjective question...would you use the Action delegate to avoid duplication of code?

    - by Seth Spearman
    Hello, I just asked a question that helps about using generics (or polymorphism) to avoid duplication of code. I am really trying to follow the DRY principle. So I just ran into the following code... Sub OutputDataToExcel() OutputLine("Output DataBlocks", 1) OutputDataBlocks() OutputLine("") OutputLine("Output Numbered Inventory", 1) OutputNumberedInventory() OutputLine("") OutputLine("Output Item Summaries", 1) OutputItemSummaries() OutputLine("") End Sub Should I rewrite this code to be as follows using the Action delegate... Sub OutputDataToExcel() OutputData("Output DataBlocks", New Action(AddressOf OutputDataBlocks)) OutputData("Output Numbered Inventory", New Action(AddressOf OutputNumberedInventory)) OutputData("Output Item Summaries", New Action(AddressOf OutputItemSummaries)) End Sub Sub OutputData(ByVal outputDescription As String, ByVal outputType As Action) OutputLine(outputDescription, 1) outputType() OutputLine("") End Sub I realize this question is subjective. I am just wondering about how religiously you follow DRY. Would you do this? Seth

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  • How do I MVVM-ize this MouseDown code in my WPF 3D app?

    - by DanM
    In my view, I have: <UserControl x:Class ... MouseDown="UserControl_MouseDown"> <Viewport3D Name="Viewport" Grid.Column="0"> ... </Viewport3D > </UserControl> In my code-behind, I have: private void UserControl_MouseDown(object sender, MouseButtonEventArgs e) { ((MapPanelViewModel)DataContext).OnMouseDown(e, Viewport); } And in my view-model, I have: public void OnMouseDown(MouseEventArgs e, Viewport3D viewport) { var range = new LineRange(); var isValid = ViewportInfo.Point2DtoPoint3D(viewport, e.GetPosition(viewport), out range); if (!isValid) MouseCoordinates = "(no data)"; else { var point3D = range.PointFromZ(0); var point = ViewportInfo.Point3DtoPoint2D(viewport, point3D); MouseCoordinates = e.GetPosition(viewport).ToString() + "\n" + point3D + "\n" + point; } } I really don't have a good sense of how to handle mouse events with MVVM. I always just end up putting them in the code-behind and casting the DataContext as SomeViewModel, then passing the MouseEventArgs on to a handler in my view-model. That's bad enough already, but in this case, I'm actually passing in a control (a Viewport3D), which is necessary for translating coordinates between 2D and 3D. Any suggestions on how to make this more in tune with MVVM?

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  • Where does Internet Explorer store saved passwords?

    - by Ian Boyd
    Where does Internet Explorer store saved passwords? And since this is a programming site, i'm not literally asking for the location where IE stores passwords, but which API ie uses to save passwords. At first i assumed that Microsoft was using the standard api: CredRead CredWrite which is used to save domain and generic program/web-site credentials. CredRead/CredWrite turn around and use CryptProtectData CryptUnprotectData to encrypt data with the current user's account. CredRead/CredWrite then store the data in some magical location, which contents you can see from the control panel: But i don't see IE passwords in there. So ie doesn't store passwords using CredRead/CredWrite. What api does IE use to store passwords, and if it uses CryptProtectData, where does it then store the protected data?

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  • Session Id in url and/or cookie? [closed]

    - by Jacco
    Most people advice against rewriting every (internal) url to include the sessionId (both GET and POST). The standard argument against it seems to be:   If an attacker gets hold of the sessionId, they can hijack the session.   With the sessionId in the url, it easily leaks to the attacker (by referer etc.) But what if you put the sessionId in both an (encrypted) cookie and the url. if the sessionId in either the cookie or the url is missing or if they do not match, decline the request. Let's pretend the website in question is free of xss holes, the cookie encryption is strong enough, etc. etc. Then what is the increased risk of rewriting every url to include the sessionId? UPDATE: @Casper That is a very good point. so up to now there are 2 reasons: bad for search engines / SEO if used in public part of the website can cause trouble when users post an url with a session Id on a forum, send it trough email or bookmark the page apart from the:   It increases the security risk, but it is not clear what the increased risk is. some background info: I've a website that offers blog-like service to travellers. I cannot be sure cookies work nor can I require cookies to work. Most computers in internet cafes are old and not (even close to) up-to-date. The user has no control over them and the connection can be very unreliable for some more 'off the beaten path' locations. Binding the session to an IP-address is not possible, some places use load-balancing proxies with multiple IP addresses. (and from China there is The Great Firewall). Upon receiving the first cookie back, I flag cookies as mandatory. However, if the cookie was flagged as mandatory but not there, I ask for their password once more, knowing their session from the url. (Also cookies have a 1 time token in them, but that's not the point of this question). UPDATE 2: The conclusion seems to be that there are no extra *security* issues when you expose you session id trough the URL while also keeping a copy of the session id in an encrypted cookie. Do not hesitate to add additional information about any possible security implications

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  • Revisiting .NET, but what should I focus on?

    - by Wayne M
    After about a two-year hiatus, I'm brushing up on my .NET skills to find a .NET job (my previous two positions have very little development, or development using legacy technologies, so apart from a few very minor apps I have not touched .NET in close to two years). I'm aware of things like ASP.NET MVC, and I have previously read on things like NHibernate and DI/IOC, albeit I have yet to use them apart from very trivial "Hello World" type applications. I have a subscription to Rob Conery's Tekpub website and occasionally watch these videos when I have free time. My concern is this: I don't live in a very technical area. I would be surprised if any but the most tech-savvy companies have heard of, let alone use, ASP.NET MVC, NHibernate (or even LINQ/EF), or know about IoC. I would be willing to bet a large sum of money that 95% of the possible jobs I could obtain will use the following: Visual Source Safe, if any VCS at all ASP.NET 2.0 Webforms (3.5 if lucky) Raw ADO.NET on top of a very thin implementation of the Gateway pattern Stored Procedures in the database for most CRUD operations Gratuitous use of code-behind, with a Service layer if I'm lucky If I were extremely lucky, I might find a shop that has heard of ORMs and either uses one, or has wrote their own data abstraction. Also if I were lucky, the company would be using Model-View-Presenter. In light of this I'm not sure what I should focus on learning. Personally, I would prefer to be using the latest stuff - ASP.NET MVC, NHibernate, jQuery, WCF etc. Reality says I should go back to the basics, since it looks like most potential opportunities aren't going to be anywhere near the cutting edge, or anywhere close to it. And, as much as I would like to find a position and start to show the other developers the benefits, in my past experience this has usually resulted in my being fired for "not being a team player" and doing things the bad old way. So, I am curious how you would approach a situation like this? What should I focus on, in order to A) Reaquaint myself with .NET, and B) Prepare myself to obtain a .NET job again that is more than likely going to use techniques that I and most other knowledgeable developers will scoff at?

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  • C# Design How to Elegantly wrap a DAL class

    - by guazz
    I have an application which uses MyGeneration's dOODads ORM to generate it's Data Access Layer. dOODad works by generating a persistance class for each table in the database. It works like so: // Load and Save Employees emps = new Employees(); if(emps.LoadByPrimaryKey(42)) { emps.LastName = "Just Got Married"; emps.Save(); } // Add a new record Employees emps = new Employees(); emps.AddNew(); emps.FirstName = "Mr."; emps.LastName = "dOOdad"; emps.Save(); // After save the identity column is already here for me. int i = emps.EmployeeID; // Dynamic Query - All Employees with 'A' in thier last name Employees emps = new Employees(); emps.Where.LastName.Value = "%A%"; emps.Where.LastName.Operator = WhereParameter.Operand.Like; emps.Query.Load(); For the above example(i.e. Employees DAL object) I would like to know what is the best method/technique to abstract some of the implementation details on my classes. I don't believe that an Employee class should have Employees(the DAL) specifics in its methods - or perhaps this is acceptable? Is it possible to implement some form of repository pattern? Bear in mind that this is a high volume, perfomacne critical application. Thanks, j

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  • How to handle payment types with varying properties in the most elegant way.

    - by Byron Sommardahl
    I'm using ASP.NET MVC 2. Keeping it simple, I have three payment types: credit card, e-check, or "bill me later". I want to: choose one payment type display some fields for one payment type in my view run some logic using those fields (specific to the type) display a confirmation view run some more logic using those fields (specific to the type) display a receipt view Each payment type has fields specific to the type... maybe 2 fields, maybe more. For now, I know how many and what fields, but more could be added. I believe the best thing for my views is to have a partial view per payment type to handle the different fields and let the controller decide which partial to render (if you have a better option, I'm open). My real problem comes from the logic that happens in the controller between views. Each payment type has a variable number of fields. I'd like to keep everything strongly typed, but it feels like some sort of dictionary is the only option. Add to that specific logic that runs depending on the payment type. In an effort to keep things strongly typed, I've created a class for each payment type. No interface or inherited type since the fields are different per payment type. Then, I've got a Submit() method for each payment type. Then, while the controller is deciding which partial view to display, it also assigns the target of the submit action. This is not elegant solution and feels very wrong. I'm reaching out for a hand. How would you do this?

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  • How to handle ViewModel and Database in C#/WPF/MVVM App

    - by Mike B
    I have a task management program with a "Urgency" field. Valid values are Int16 currently mapped to 1 (High), 2 (Medium), 3 (Low), 4 (None) and 99 (Closed). The urgency field is used to rank tasks as well as alter the look of the items in the list and detail view. When a user is editing or adding a new task they select or view the urgency in a ComboBox. A Converter passes Strings to replace the Ints. The urgency collection is so simple I did not make it a table in the database, instead it is a, ObservableCollection(Int16) that is populated by a method. Since the same screen may be used to view a closed task the "Closed" urgency must be in the ItemsSource but I do not want the user to be able to select it. In order to prevent the user from being able to select that item in the ComboBox but still be able to see it if the item in the database has that value should I... Manually disable the item in the ComboBox in code or Xaml (I doubt it) Change the Urgency collection from an Int16 to an Object with a Selectable Property that the isEnabled property of the ComboBoxItem Binds to. Do as in 2 but also separate the urgency information into its own table in the database with a foreign key in the Tasks table None of the above (I suspect this is the correct answer) I ask this because this is a learning project (My first real WPF and first ever MVVM project). I know there is rarely one Right way to do something but I want to make sure I am learning in a reasonable manner since it if far harder to Unlearn bad habits Thanks Mike

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  • What can tables do that CSS positioning cannot?

    - by Jeremy Lew
    I know there are various good arguments preferring css positioning over table-based layouts. What I'm wondering is whether the CSS model is complete (assuming a relatively modern browser) with respect to ALL of the capabilities of tables. Are there layouts that tables can achieve that are impossible or impractical with CSS?

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  • naming conventions for buttons in user interface

    - by Samuel
    User interface for web applications in general contain various buttons for performing CRUD operations. What would be the suggested naming convention for button labels while performing the following actions.. User creation (Add User... or Add User or Add user) Event creation (Add Event... or Add Event or Add event) View users button (List All Users or List All users or List all users ) Most of the sites seem to contain the last option (e.g. Add user) where the first alphabet in the word is capitalized and rest all are lower case). What would be a better practice here?

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  • QT's QGraphicsview clickable icon on screen

    - by goodwince
    I'm working on a project with QT and am trying to draw icons from a database. I have auxiliary information in the table that I would like to display if the user chooses to see it (i.e. the x,y of the icon and some other options from database). I am debating on would it be better to go through and just redraw all the icons with this information added, or do some sort of looping through the icons and setting some value to true to display the information. Thanks in advance.

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  • MySQL Query Select using sub-select takes too long

    - by True Soft
    I noticed something strange while executing a select from 2 tables: SELECT * FROM table_1 WHERE id IN ( SELECT id_element FROM table_2 WHERE column_2=3103); This query took approximatively 242 seconds. But when I executed the subquery SELECT id_element FROM table_2 WHERE column_2=3103 it took less than 0.002s (and resulted 2 rows). Then, when I did SELECT * FROM table_1 WHERE id IN (/* prev.result */) it was the same: 0.002s. I was wondering why MySQL is doing the first query like that, taking much more time than the last 2 queries separately? Is it an optimal solution for selecting something based from the results of a sub-query? Other details: table_1 has approx. 9000 rows, and table_2 has 90000 rows. After I added an index on column_2 from table_2, the first query took 0.15s.

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  • How to correctly refactor this?

    - by kane77
    I have trouble finding way to correctly refactor this code so that there would be as little duplicate code as possible, I have a couple of methods like this (pseudocode): public List<Something> parseSomething(Node n){ List<Something> somethings = new ArrayList<Something>(); initialize(); sameCodeInBothClasses(); List<Node> nodes = getChildrenByName(n, "somename"); for(Node n:nodes){ method(); actionA(); somethings.add(new Something(actionB()); } return somethings; } methods sameCodeInBothClasses() are same in all classes but where it differs is what hapens in for loop actionA() and it also adds an element to the List of different type. Should I use Strategy pattern for the different parts inside loop? What about the return value (The type of list differs), should the method return just List<Object> that I would then cast to appropriate type? Should I pass the class I want to return as parameter?

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  • Best Practice for Images with Codeigniter : Generating Thumbs or Resizing on the Fly

    - by Steve K
    Hi all, I know there’s been a good deal written on thumbnail generation and the like with CI, but I wanted to explain what I’ve made and see what kind of best-practice advice I could find. Here’s my story… Currently, I have a site which allows users to upload collections of photos to projects they’ve created after first creating an account. Upon account creation, the site generates folders for the users in the following fashion for each of five pre-defined projects: /students/username/project_num/images/thumbs/ (This is to say that within a pre-created students folder, the username, project_num, images and thumbs folders are created recursively five times.) When a user uploads images to a project, I have a gallery controller which uploads the full images into the images folder for the project_num, and then creates a smaller thumbnail which maintains its ratio. So far so good. On the index page of the site, where these thumbnails and full images are displayed, I had a bit of a brain lapse, thinking I could simply output the full image while resizing it via css for a ‘medium-size’ image which would lead to the full-size image when clicked. (To be clear, the path is: Click on thumbnail— Load scaled full-size (medium-size) image via ajax into a display area above thumbs— Click on medium-sized image— Load full size image via lightbox, or something of that nature.) I have everything working to this point, except, as one might imagine, resizing the full-sized images with css doesn’t maintain aspect ratio for the thumbs, which means I need to find the best way to resize these. In thinking about it, I figured I had two options: I could resize the image on the fly when the user clicks a thumbnail to load the medium-sized image via ajax. (I have a method ‘get_image($url)’ in my gallery controller which simply loads a view with an image tag and the image source passed to it, etc.) I thought perhaps I could send it first to my gallery model, resize it there on the fly, and send it on to the view. The problem I’m having is that resizing it on the fly and echoing it out gives me the raw image data (I apologize, I don’t know that’s the right term). I’ve tried using data_uris to format the raw data into something echoable, but with no success. Is this method possible? The second option I considered was to generate a second medium-sized thumbnail when the user uploads the image with maintain_ratio set to true. This method is slightly less ideal, given that when providing a way for the user to delete their projects, I’ll need to scan for an additional set of images to delete. Not a huge deal, definitely, but something I figured could be avoided by generating the medium-sized image on the fly. I hope I’ve been clear in my explanations, if long-winded! I’m very curious to see what suggestions folks have about the best way to handle this. Much thanks for reading, and any suggestions are much-appreciated! Steve K.

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  • MVVM && IOC && Sub-ViewModels

    - by Lee Treveil
    I have a ViewModel, it takes two parameters in the constructor that are of the same type: public class CustomerComparerViewModel { public CustomerComparerViewModel(CustomerViewModel customerViewModel1, CustomerViewModel customerViewModel2) { } } public class CustomerViewModel { public string FirstName { get; set; } public string LastName { get; set; } } If I wasn't using IOC I could just new up the viewmodel and pass the sub-viewmodels in. I could package the two viewmodels into one class and pass that into the constructor but if I had another viewmodel that only needed one CustomerViewModel I would need to pass in something that the viewmodel does not need. How do I go about dealing with this using IOC? I'm using Ninject btw. Thanks

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  • Is this so bad when using MySQL queries in PHP?

    - by alex
    I need to update a lot of rows, per a user request. It is a site with products. I could... Delete all old rows for that product, then loop through string building a new INSERT query. This however will lose all data if the INSERT fails. Perform an UPDATE through each loop. This loop currently iterates over 8 items, but in the future it may get up to 15. This many UPDATEs doesn't sound like too good an idea. Change DB Schema, and add an auto_increment Id to the rows. Then first do a SELECT, get all old rows ids in a variable, perform one INSERT, and then a DELETE WHERE IN SET. What is the usual practice here? Thanks

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  • ORM Persistence by Reachability violates Aggregate Root Boundaries?

    - by Johannes Rudolph
    Most common ORMs implement persistence by reachability, either as the default object graph change tracking mechanism or an optional. Persistence by reachability means the ORM will check the aggregate roots object graph and determines wether any objects are (also indirectly) reachable that are not stored inside it's identity map (Linq2Sql) or don't have their identity column set (NHibernate). In NHibernate this corresponds to cascade="save-update", for Linq2Sql it is the only supported mechanism. They do both, however only implement it for the "add" side of things, objects removed from the aggregate roots graph must be marked for deletion explicitly. In a DDD context one would use a Repository per Aggregate Root. Objects inside an Aggregate Root may only hold references to other Aggregate Roots. Due to persistence by reachability it is possible this other root will be inserted in the database event though it's corresponding repository wasn't invoked at all! Consider the following two Aggregate Roots: Contract and Order. Request is part of the Contract Aggregate. The object graph looks like Contract->Request->Order. Each time a Contractor makes a request, a corresponding order is created. As this involves two different Aggregate Roots, this operation is encapsulated by a Service. //Unit Of Work begins Request r = ...; Contract c = ContractRepository.FindSingleByKey(1); Order o = OrderForRequest(r); // creates a new order aggregate r.Order = o; // associates the aggregates c.Request.Add(r); ContractRepository.SaveOrUpdate(c); // OrderAggregate is reachable and will be inserted Since this Operation happens in a Service, I could still invoke the OrderRepository manually, however I wouldn't be forced to!. Persistence by reachability is a very useful feature inside Aggregate Roots, however I see no way to enforce my Aggregate Boundaries.

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  • Implement password recovery best practice

    - by Enrique
    Hello I want to to implement password recovery in my web application. I'd like to avoid using secret questions. I could just send the password by e-mail but I think it would be risky. Maybe I could generate a new temporary random password and send it by e-mail but I think it is as risky as the above point. Can I send a url by e-mail for example http://mysite.com/token=xxxx where xxxx is a random token associated with the user. So when the user navigates to that url he/she can reset the password. Any ideas?

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  • MVVM Madness: Commands

    - by JP
    I like MVVM. I don't love it, but like it. Most of it makes sense. But, I keep reading articles that encourage you to write a lot of code so that you can write XAML and don't have to write any code in the code-behind. Let me give you an example. Recently I wanted to hookup a command in my ViewModel to a ListView MouseDoubleClickEvent. I wasn't quite sure how to do this. Fortunately, Google has answers for everything. I found the following articles: http://blog.functionalfun.net/2008/09/hooking-up-commands-to-events-in-wpf.html http://joyfulwpf.blogspot.com/2009/05/mvvm-invoking-command-on-attached-event.html http://sachabarber.net/?p=514 http://geekswithblogs.net/HouseOfBilz/archive/2009/08/27/adventures-in-mvvm-ndash-binding-commands-to-any-event.aspx http://marlongrech.wordpress.com/2008/12/13/attachedcommandbehavior-v2-aka-acb/ While the solutions were helpful in my understanding of commands, there were problems. Some of the aforementioned solutions rendered the WPF designer unusable because of a common hack of appending "Internal" after a dependency property; the WPF designer can't find it, but the CLR can. Some of the solutions didn't allow multiple commands to the same control. Some of the solutions didn't allow parameters. After experimenting for a few hours I just decided to do this: private void ListView_MouseDoubleClick(object sender, MouseButtonEventArgs e) { ListView lv = sender as ListView; MyViewModel vm = this.DataContext as MyViewModel; vm.DoSomethingCommand.Execute(lv.SelectedItem); } So, MVVM purists, please tell me what's wrong with this? I can still Unit test my command. This seems very practical, but seems to violate the guideline of "ZOMG... you have code in your code-behind!!!!" Please share your thoughts. Thanks in advance.

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  • Conditional Markup in aspx

    - by Dynde
    Hi... I have a ListView. If I want to base the html markup on a condition in respects to the databound item, what would be the best way to do that? What I mean is, is there any other way then putting <% % if/else blocks directly in the markup? I'm aware that a really ugly way of doing it, is putting html markup in the database field, and just let the Eval() squeeze out the proper markup (I'm not doing that). I would like to avoid putting actual <% % C# blocks in the code as well. Any good ideas?

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  • Question About Example In Robert C Martin's _Clean Code_

    - by Jonah
    This is a question about the concept of a function doing only one thing. It won't make sense without some relevant passages for context, so I'll quote them here. They appear on pgs 37-38: To say this differently, we want to be able to read the program as though it were a set of TO paragraphs, each of which is describing the current level of abstraction and referencing subsequent TO paragraphs at the next level down. To include the setups and teardowns, we include setups, then we include the test page content, and then we include the teardowns. To include the setups, we include the suite setup if this is a suite, then we include the regular setup. It turns out to be very dif?cult for programmers to learn to follow this rule and write functions that stay at a single level of abstraction. But learning this trick is also very important. It is the key to keeping functions short and making sure they do “one thing.” Making the code read like a top-down set of TO paragraphs is an effective technique for keeping the abstraction level consistent. He then gives the following example of poor code: public Money calculatePay(Employee e) throws InvalidEmployeeType { switch (e.type) { case COMMISSIONED: return calculateCommissionedPay(e); case HOURLY: return calculateHourlyPay(e); case SALARIED: return calculateSalariedPay(e); default: throw new InvalidEmployeeType(e.type); } } and explains the problems with it as follows: There are several problems with this function. First, it’s large, and when new employee types are added, it will grow. Second, it very clearly does more than one thing. Third, it violates the Single Responsibility Principle7 (SRP) because there is more than one reason for it to change. Fourth, it violates the Open Closed Principle8 (OCP) because it must change whenever new types are added. Now my questions. To begin, it's clear to me how it violates the OCP, and it's clear to me that this alone makes it poor design. However, I am trying to understand each principle, and it's not clear to me how SRP applies. Specifically, the only reason I can imagine for this method to change is the addition of new employee types. There is only one "axis of change." If details of the calculation needed to change, this would only affect the submethods like "calculateHourlyPay()" Also, while in one sense it is obviously doing 3 things, those three things are all at the same level of abstraction, and can all be put into a TO paragraph no different from the example one: TO calculate pay for an employee, we calculate commissioned pay if the employee is commissioned, hourly pay if he is hourly, etc. So aside from its violation of the OCP, this code seems to conform to Martin's other requirements of clean code, even though he's arguing it does not. Can someone please explain what I am missing? Thanks.

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