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• Keep coding the wrong way to remain consistent? [closed]

  - by bwalk2895

  Possible Duplicate: Code maintenance: keeping a bad pattern when extending new code for being consistent, or not? To keep things simple let's say I am responsible for maintaining two applications, AwesomeApp and BadApp (I am responsible for more and no that is not their actual names). AwesomeApp is a greenfield project I have been working on with other members on my team. It was coded using all the fancy buzzwords, Multilayer, SOA, SOLID, TDD, and so on. It represents the direction we want to go as a team. BadApp is a application that has been around for a long time. The architecture suffers from many sins, namely everything is tightly coupled together and it is not uncommon to get a circular dependency error from the compiler, it is almost impossible to unit test, large classes, duplicate code, and so on. We have a plan to rewrite the application following the standards established by AwesomeApp, but that won't happen for a while. I have to go into BadApp and fix a bug, but after spending months coding what I consider correctly, I really don't want do continue perpetuate bad coding practices. However, the way AwesomeApp is coded is vastly different from the way BadApp is coded. I fear implementing the "correct" way would cause confusion for other developers who have to maintain the application. Question: Is it better to keep coding the wrong way to remain consistent with the rest of the code in the application (knowing it will be replaced) or is it better to code the right way with an understanding it could cause confusion because it is so much different? To give you an example. There is a large class (1000+ lines) with several functions. One of the functions is to calculate a date based on an enumerated value. Currently the function handles all the various calculations. The function relies on no other functionality within the class. It is self contained. I want to break the function into smaller functions (at the very least) and put them into their own classes and hide those classes behind an interface (at the most) and use the factory pattern to instantiate the date classes. If I just broke it out into smaller functions within the class it would follow the existing coding standard. The extra steps are to start following some of the SOLID principles.

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• Does OO, TDD, and Refactoring to Smaller Functions affect Speed of Code?

  - by Dennis

  In Computer Science field, I have noticed a notable shift in thinking when it comes to programming. The advice as it stands now is write smaller, more testable code refactor existing code into smaller and smaller chunks of code until most of your methods/functions are just a few lines long write functions that only do one thing (which makes them smaller again) This is a change compared to the "old" or "bad" code practices where you have methods spanning 2500 lines, and big classes doing everything. My question is this: when it call comes down to machine code, to 1s and 0s, to assembly instructions, should I be at all concerned that my class-separated code with variety of small-to-tiny functions generates too much extra overhead? While I am not exactly familiar with how OO code and function calls are handled in ASM in the end, I do have some idea. I assume that each extra function call, object call, or include call (in some languages), generate an extra set of instructions, thereby increasing code's volume and adding various overhead, without adding actual "useful" code. I also imagine that good optimizations can be done to ASM before it is actually ran on the hardware, but that optimization can only do so much too. Hence, my question -- how much overhead (in space and speed) does well-separated code (split up across hundreds of files, classes, and methods) actually introduce compared to having "one big method that contains everything", due to this overhead? UPDATE for clarity: I am assuming that adding more and more functions and more and more objects and classes in a code will result in more and more parameter passing between smaller code pieces. It was said somewhere (quote TBD) that up to 70% of all code is made up of ASM's MOV instruction - loading CPU registers with proper variables, not the actual computation being done. In my case, you load up CPU's time with PUSH/POP instructions to provide linkage and parameter passing between various pieces of code. The smaller you make your pieces of code, the more overhead "linkage" is required. I am concerned that this linkage adds to software bloat and slow-down and I am wondering if I should be concerned about this, and how much, if any at all, because current and future generations of programmers who are building software for the next century, will have to live with and consume software built using these practices. UPDATE: Multiple files I am writing new code now that is slowly replacing old code. In particular I've noted that one of the old classes was a ~3000 line file (as mentioned earlier). Now it is becoming a set of 15-20 files located across various directories, including test files and not including PHP framework I am using to bind some things together. More files are coming as well. When it comes to disk I/O, loading multiple files is slower than loading one large file. Of course not all files are loaded, they are loaded as needed, and disk caching and memory caching options exist, and yet still I believe that loading multiple files takes more processing than loading a single file into memory. I am adding that to my concern.

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• Developing web apps using ASP.NET MVC 3, Razor and EF Code First - Part 2

  - by shiju

  In my previous post Developing web apps using ASP.NET MVC 3, Razor and EF Code First - Part 1, we have discussed on how to work with ASP.NET MVC 3 and EF Code First for developing web apps. We have created generic repository and unit of work with EF Code First for our ASP.NET MVC 3 application and did basic CRUD operations against a simple domain entity. In this post, I will demonstrate on working with domain entity with deep object graph, Service Layer and View Models and will also complete the rest of the demo application. In the previous post, we have done CRUD operations against Category entity and this post will be focus on Expense entity those have an association with Category entity. You can download the source code from http://efmvc.codeplex.com . The following frameworks will be used for this step by step tutorial.    1. ASP.NET MVC 3 RTM    2. EF Code First CTP 5    3. Unity 2.0 Domain Model Category Entity public class Category   {       public int CategoryId { get; set; }       [Required(ErrorMessage = "Name Required")]       [StringLength(25, ErrorMessage = "Must be less than 25 characters")]       public string Name { get; set;}       public string Description { get; set; }       public virtual ICollection<Expense> Expenses { get; set; }   } Expense Entity public class Expense     {                public int ExpenseId { get; set; }                public string  Transaction { get; set; }         public DateTime Date { get; set; }         public double Amount { get; set; }         public int CategoryId { get; set; }         public virtual Category Category { get; set; }     } We have two domain entities - Category and Expense. A single category contains a list of expense transactions and every expense transaction should have a Category. Repository class for Expense Transaction Let’s create repository class for handling CRUD operations for Expense entity public class ExpenseRepository : RepositoryBase<Expense>, IExpenseRepository     {     public ExpenseRepository(IDatabaseFactory databaseFactory)         : base(databaseFactory)         {         }                } public interface IExpenseRepository : IRepository<Expense> { } Service Layer If you are new to Service Layer, checkout Martin Fowler's article Service Layer . According to Martin Fowler, Service Layer defines an application's boundary and its set of available operations from the perspective of interfacing client layers. It encapsulates the application's business logic, controlling transactions and coordinating responses in the implementation of its operations. Controller classes should be lightweight and do not put much of business logic onto it. We can use the service layer as the business logic layer and can encapsulate the rules of the application. Let’s create a Service class for coordinates the transaction for Expense public interface IExpenseService {     IEnumerable<Expense> GetExpenses(DateTime startDate, DateTime ednDate);     Expense GetExpense(int id);             void CreateExpense(Expense expense);     void DeleteExpense(int id);     void SaveExpense(); } public class ExpenseService : IExpenseService {     private readonly IExpenseRepository expenseRepository;            private readonly IUnitOfWork unitOfWork;     public ExpenseService(IExpenseRepository expenseRepository, IUnitOfWork unitOfWork)     {                  this.expenseRepository = expenseRepository;         this.unitOfWork = unitOfWork;     }     public IEnumerable<Expense> GetExpenses(DateTime startDate, DateTime endDate)     {         var expenses = expenseRepository.GetMany(exp => exp.Date >= startDate && exp.Date <= endDate);         return expenses;     }     public void CreateExpense(Expense expense)     {         expenseRepository.Add(expense);         unitOfWork.Commit();     }     public Expense GetExpense(int id)     {         var expense = expenseRepository.GetById(id);         return expense;     }     public void DeleteExpense(int id)     {         var expense = expenseRepository.GetById(id);         expenseRepository.Delete(expense);         unitOfWork.Commit();     }     public void SaveExpense()     {         unitOfWork.Commit();     } }   View Model for Expense Transactions In real world ASP.NET MVC applications, we need to design model objects especially for our views. Our domain objects are mainly designed for the needs for domain model and it is representing the domain of our applications. On the other hand, View Model objects are designed for our needs for views. We have an Expense domain entity that has an association with Category. While we are creating a new Expense, we have to specify that in which Category belongs with the new Expense transaction. The user interface for Expense transaction will have form fields for representing the Expense entity and a CategoryId for representing the Category. So let's create view model for representing the need for Expense transactions. public class ExpenseViewModel {     public int ExpenseId { get; set; }       [Required(ErrorMessage = "Category Required")]     public int CategoryId { get; set; }       [Required(ErrorMessage = "Transaction Required")]     public string Transaction { get; set; }       [Required(ErrorMessage = "Date Required")]     public DateTime Date { get; set; }       [Required(ErrorMessage = "Amount Required")]     public double Amount { get; set; }       public IEnumerable<SelectListItem> Category { get; set; } } The ExpenseViewModel is designed for the purpose of View template and contains the all validation rules. It has properties for mapping values to Expense entity and a property Category for binding values to a drop-down for list values of Category. Create Expense transaction Let’s create action methods in the ExpenseController for creating expense transactions public ActionResult Create() {     var expenseModel = new ExpenseViewModel();     var categories = categoryService.GetCategories();     expenseModel.Category = categories.ToSelectListItems(-1);     expenseModel.Date = DateTime.Today;     return View(expenseModel); } [HttpPost] public ActionResult Create(ExpenseViewModel expenseViewModel) {                      if (!ModelState.IsValid)         {             var categories = categoryService.GetCategories();             expenseViewModel.Category = categories.ToSelectListItems(expenseViewModel.CategoryId);             return View("Save", expenseViewModel);         }         Expense expense=new Expense();         ModelCopier.CopyModel(expenseViewModel,expense);         expenseService.CreateExpense(expense);         return RedirectToAction("Index");              } In the Create action method for HttpGet request, we have created an instance of our View Model ExpenseViewModel with Category information for the drop-down list and passing the Model object to View template. The extension method ToSelectListItems is shown below   public static IEnumerable<SelectListItem> ToSelectListItems(         this IEnumerable<Category> categories, int  selectedId) {     return           categories.OrderBy(category => category.Name)                 .Select(category =>                     new SelectListItem                     {                         Selected = (category.CategoryId == selectedId),                         Text = category.Name,                         Value = category.CategoryId.ToString()                     }); } In the Create action method for HttpPost, our view model object ExpenseViewModel will map with posted form input values. We need to create an instance of Expense for the persistence purpose. So we need to copy values from ExpenseViewModel object to Expense object. ASP.NET MVC futures assembly provides a static class ModelCopier that can use for copying values between Model objects. ModelCopier class has two static methods - CopyCollection and CopyModel.CopyCollection method will copy values between two collection objects and CopyModel will copy values between two model objects. We have used CopyModel method of ModelCopier class for copying values from expenseViewModel object to expense object. Finally we did a call to CreateExpense method of ExpenseService class for persisting new expense transaction. List Expense Transactions We want to list expense transactions based on a date range. So let’s create action method for filtering expense transactions with a specified date range. public ActionResult Index(DateTime? startDate, DateTime? endDate) {     //If date is not passed, take current month's first and last dte     DateTime dtNow;     dtNow = DateTime.Today;     if (!startDate.HasValue)     {         startDate = new DateTime(dtNow.Year, dtNow.Month, 1);         endDate = startDate.Value.AddMonths(1).AddDays(-1);     }     //take last date of start date's month, if end date is not passed     if (startDate.HasValue && !endDate.HasValue)     {         endDate = (new DateTime(startDate.Value.Year, startDate.Value.Month, 1)).AddMonths(1).AddDays(-1);     }     var expenses = expenseService.GetExpenses(startDate.Value ,endDate.Value);     //if request is Ajax will return partial view     if (Request.IsAjaxRequest())     {         return PartialView("ExpenseList", expenses);     }     //set start date and end date to ViewBag dictionary     ViewBag.StartDate = startDate.Value.ToShortDateString();     ViewBag.EndDate = endDate.Value.ToShortDateString();     //if request is not ajax     return View(expenses); } We are using the above Index Action method for both Ajax requests and normal requests. If there is a request for Ajax, we will call the PartialView ExpenseList. Razor Views for listing Expense information Let’s create view templates in Razor for showing list of Expense information ExpenseList.cshtml @model IEnumerable<MyFinance.Domain.Expense>   <table>         <tr>             <th>Actions</th>             <th>Category</th>             <th>                 Transaction             </th>             <th>                 Date             </th>             <th>                 Amount             </th>         </tr>       @foreach (var item in Model) {              <tr>             <td>                 @Html.ActionLink("Edit", "Edit",new { id = item.ExpenseId })                 @Ajax.ActionLink("Delete", "Delete", new { id = item.ExpenseId }, new AjaxOptions { Confirm = "Delete Expense?", HttpMethod = "Post", UpdateTargetId = "divExpenseList" })             </td>              <td>                 @item.Category.Name             </td>             <td>                 @item.Transaction             </td>             <td>                 @String.Format("{0:d}", item.Date)             </td>             <td>                 @String.Format("{0:F}", item.Amount)             </td>         </tr>          }       </table>     <p>         @Html.ActionLink("Create New Expense", "Create") |         @Html.ActionLink("Create New Category", "Create","Category")     </p> Index.cshtml @using MyFinance.Helpers; @model IEnumerable<MyFinance.Domain.Expense> @{     ViewBag.Title = "Index"; }    <h2>Expense List</h2>    <script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery-ui.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.ui.datepicker.js")" type="text/javascript"></script> <link href="@Url.Content("~/Content/jquery-ui-1.8.6.custom.css")" rel="stylesheet" type="text/css" />      @using (Ajax.BeginForm(new AjaxOptions{ UpdateTargetId="divExpenseList", HttpMethod="Get"})) {     <table>         <tr>         <td>         <div>           Start Date: @Html.TextBox("StartDate", Html.Encode(String.Format("{0:mm/dd/yyyy}", ViewData["StartDate"].ToString())), new { @class = "ui-datepicker" })         </div>         </td>         <td><div>            End Date: @Html.TextBox("EndDate", Html.Encode(String.Format("{0:mm/dd/yyyy}", ViewData["EndDate"].ToString())), new { @class = "ui-datepicker" })          </div></td>          <td> <input type="submit" value="Search By TransactionDate" /></td>         </tr>     </table>         }   <div id="divExpenseList">             @Html.Partial("ExpenseList", Model)     </div> <script type="text/javascript">     $().ready(function () {         $('.ui-datepicker').datepicker({             dateFormat: 'mm/dd/yy',             buttonImage: '@Url.Content("~/Content/calendar.gif")',             buttonImageOnly: true,             showOn: "button"         });     }); </script> Ajax search functionality using Ajax.BeginForm The search functionality of Index view is providing Ajax functionality using Ajax.BeginForm. The Ajax.BeginForm() method writes an opening <form> tag to the response. You can use this method in a using block. In that case, the method renders the closing </form> tag at the end of the using block and the form is submitted asynchronously by using JavaScript. The search functionality will call the Index Action method and this will return partial view ExpenseList for updating the search result. We want to update the response UI for the Ajax request onto divExpenseList element. So we have specified the UpdateTargetId as "divExpenseList" in the Ajax.BeginForm method. Add jQuery DatePicker Our search functionality is using a date range so we are providing two date pickers using jQuery datepicker. You need to add reference to the following JavaScript files to working with jQuery datepicker. jquery-ui.js jquery.ui.datepicker.js For theme support for datepicker, we can use a customized CSS class. In our example we have used a CSS file “jquery-ui-1.8.6.custom.css”. For more details about the datepicker component, visit jquery UI website at http://jqueryui.com/demos/datepicker . In the jQuery ready event, we have used following JavaScript function to initialize the UI element to show date picker. <script type="text/javascript">     $().ready(function () {         $('.ui-datepicker').datepicker({             dateFormat: 'mm/dd/yy',             buttonImage: '@Url.Content("~/Content/calendar.gif")',             buttonImageOnly: true,             showOn: "button"         });     }); </script>   Source Code You can download the source code from http://efmvc.codeplex.com/ . Summary In this two-part series, we have created a simple web application using ASP.NET MVC 3 RTM, Razor and EF Code First CTP 5. I have demonstrated patterns and practices  such as Dependency Injection, Repository pattern, Unit of Work, ViewModel and Service Layer. My primary objective was to demonstrate different practices and options for developing web apps using ASP.NET MVC 3 and EF Code First. You can implement these approaches in your own way for building web apps using ASP.NET MVC 3. I will refactor this demo app on later time.

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• Entity Framework 4.3.1 Code based Migrations and Connector/Net 6.6

  - by GABMARTINEZ

   Code-based migrations is a new feature as part of the Connector/Net support for Entity Framework 4.3.1. In this tutorial we'll see how we can use it so we can keep track of the changes done to our database creating a new application using the code first approach. If you don't have a clear idea about how code first works we highly recommend you to check this subject before going further with this tutorial. Creating our Model and Database with Code First  From VS 2010  1. Create a new console application 2.  Add the latest Entity Framework official package using Package Manager Console (Tools Menu, then Library Package Manager -> Package Manager Console). In the Package Manager Console we have to type  Install-Package EntityFramework This will add the latest version of this library.  We will also need to make some changes to your config file. A <configSections> was added which contains the version you have from EntityFramework.  An <entityFramework> section was also added where you can set up some initialization. This section is optional and by default is generated to use SQL Express. Since we don't need it for now (we'll see more about it below) let's leave this section empty as shown below. 3. Create a new Model with a simple entity. 4. Enable Migrations to generate the our Configuration class. In the Package Manager Console we have to type  Enable-Migrations; This will make some changes in our application. It will create a new folder called Migrations where all the migrations representing the changes we do to our model.  It will also create a Configuration class that we'll be using to initialize our SQL Generator and some other values like if we want to enable Automatic Migrations.  You can see that it already has the name of our DbContext. You can also create you Configuration class manually. 5. Specify our Model Provider. We need to specify in our Class Configuration that we'll be using MySQLClient since this is not part of the generated code. Also please make sure you have added the MySql.Data and the MySql.Data.Entity references to your project. using MySql.Data.Entity;   // Add the MySQL.Data.Entity namespace public Configuration() { this.AutomaticMigrationsEnabled = false; SetSqlGenerator("MySql.Data.MySqlClient", new MySql.Data.Entity.MySqlMigrationSqlGenerator());    // This will add our MySQLClient as SQL Generator } 6. Add our Data Provider and set up our connection string <connectionStrings> <add name="PersonalContext" connectionString="server=localhost;User Id=root;database=Personal;" providerName="MySql.Data.MySqlClient" /> </connectionStrings> <system.data> <DbProviderFactories> <remove invariant="MySql.Data.MySqlClient" /> <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.6.2.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" /> </DbProviderFactories> </system.data> * The version recommended to use of Connector/Net is 6.6.2 or earlier. At this point we can create our database and then start working with Migrations. So let's do some data access so our database get's created. You can run your application and you'll get your database Personal as specified in our config file. Add our first migration Migrations are a great resource as we can have a record for all the changes done and will generate the MySQL statements required to apply these changes to the database. Let's add a new property to our Person class public string Email { get; set; } If you try to run your application it will throw an exception saying  The model backing the 'PersonelContext' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269). So as suggested let's add our first migration for this change. In the Package Manager Console let's type Add-Migration AddEmailColumn Now we have the corresponding class which generate the necessary operations to update our database. namespace MigrationsFromScratch.Migrations { using System.Data.Entity.Migrations; public partial class AddEmailColumn : DbMigration { public override void Up(){ AddColumn("People", "Email", c => c.String(unicode: false)); } public override void Down() { DropColumn("People", "Email"); } } } In the Package Manager Console let's type Update-Database Now you can check your database to see all changes were succesfully applied. Now let's add a second change and generate our second migration public class Person   {       [Key]       public int PersonId { get; set;}       public string Name { get; set; }       public string Address {get; set;}       public string Email { get; set; }       public List<Skill> Skills { get; set; }   }   public class Skill   {     [Key]     public int SkillId { get; set; }     public string Description { get; set; }   }   public class PersonelContext : DbContext   {     public DbSet<Person> Persons { get; set; }     public DbSet<Skill> Skills { get; set; }   } If you would like to customize any part of this code you can do that at this step. You can see there is the up method which can update your database and the down that can revert the changes done. If you customize any code you should make sure to customize in both methods. Now let's apply this change. Update-database -verbose I added the verbose flag so you can see all the SQL generated statements to be run. Downgrading changes So far we have always upgraded to the latest migration, but there may be times when you want downgrade to a specific migration. Let's say we want to return to the status we have before our last migration. We can use the -TargetMigration option to specify the migration we'd like to return. Also you can use the -verbose flag. If you like to go  back to the Initial state you can do: Update-Database -TargetMigration:$InitialDatabase  or equivalent: Update-Database -TargetMigration:0  Migrations doesn't allow by default a migration that would ocurr in a data loss. One case when you can got this message is for example in a DropColumn operation. You can override this configuration by setting AutomaticMigrationDataLossAllowed to true in the configuration class. Also you can set your Database Initializer in case you want that these Migrations can be applied automatically and you don't have to go all the way through creating a migration and updating later the changes. Let's see how. Database Initialization by Code We can specify an initialization strategy by using Database.SetInitializer (http://msdn.microsoft.com/en-us/library/gg679461(v=vs.103)). One of the strategies that I found very useful when you are at a development stage (I mean not for production) is the MigrateDatabaseToLatestVersion. This strategy will make all the necessary migrations each time there is a change in our model that needs a database replication, this also implies that we have to enable AutomaticMigrationsEnabled flag in our Configuration class. public Configuration()         {             AutomaticMigrationsEnabled = true;             AutomaticMigrationDataLossAllowed = true;             SetSqlGenerator("MySql.Data.MySqlClient", new MySql.Data.Entity.MySqlMigrationSqlGenerator());    // This will add our MySQLClient as SQL Generator          } In the new EntityFramework section of your Config file we can set this at a context level basis.  The syntax is as follows: <contexts> <context type="Custom DbContext name, Assembly name"> <databaseInitializer type="System.Data.Entity.MigrateDatabaseToLatestVersion`2[[ Custom DbContext name, Assembly name],  [Configuration class name, Assembly name]],  EntityFramework" /> </context> </contexts> In our example this would be: The syntax is kind of odd but very convenient. This way all changes will always be applied when we do any data access in our application. There are a lot of new things to explore in EF 4.3.1 and Migrations so we'll continue writing some more posts about it. Please let us know if you have any questions or comments, also please check our forums here where we keep answering questions in general for the community.  Hope you found this information useful. Happy MySQL/.Net Coding! 

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• December release of Microsoft All-In-One Code Framework is available now.

  - by Jialiang

  The code samples in Microsoft All-In-One Code Framework are updated on 2010-12-13. Download address: http://1code.codeplex.com/releases/view/57459#DownloadId=185534 Updated code sample index categorized by technologies: http://1code.codeplex.com/wikipage?title=All-In-One%20Code%20Framework%20Sample%20Catalog (it also allows you to download individual code samples instead of the entire All-In-One Code Framework sample package.) If it’s the first time that you hear about Microsoft All-In-One Code Framework, please watch the introduction video on YouTube http://www.youtube.com/watch?v=cO5Li3APU58, or read the introduction on our homepage http://1code.codeplex.com/,  and this Port25 article http://port25.technet.com/archive/2010/01/18/the-all-in-one-code-framework.aspx.  -------------- New ASP.NET Code Samples VBASPNETAJAXWebChat and CSASPNETAJAXWebChat Most of you have some experience in chatting with friends on the web. So you may want to know how to make a web chat application, it seems to be quite complicated. But ASP.NET gives you the power to buiild a chat room easily. In this code sample, we will construct our own web chat room with the amazing AJAX feature. The principle is simple relatively. As we all know, a base chat application need 4 base controls: one List control to show the chat room members, one List control to show the message list, one TextBox control to input messages and one button to send message. User inputs his message in the textbox first and then presses Send button, it will send the message to the server. The message list will update every 2 seconds to get the newest message list in the chat room from the server. We need to know, it is hard for us to make an AJAX web chat application like a windows form application because we cannot keep the connection after one web request ended. So a lot of events which communicates between client side and server side cannot be realized. The common workaround is to make web requests in every some seconds to check whether the server side has been updated. But another technique called COMET makes it possible. But it is different with AJAX and will not be talked in details in this KB. For more details about COMET, we can get some clues from the Reference.   CSASPNETCurrentOnlineUserList and VBASPNETCurrentOnlineUserList This sample demos a system that needs to display a list of current online users' information. As a matter of fact, Membership.GetNumberOfUsersOnline Method  can get the number of online users and there is a convenient approach to check whether the user is online by using Membership.GetUser(string userName).IsOnline property,however many asp.net projects are not using membership.So in this case,the sample shows how to display a list of current online users' information without using membership provider. It is not difficult to check whether the user is online by using session.Many projects tend to be used “Session_End” event to mark a user as “Offline”,however ,it may not be a good idea,because it can’t detect the user status accurately. In addition, "Session_End" event is only available in the "InProc" session mode. If you are storing session states in the State Server or SQL Server, "Session_End" event will never fire. To handle this issue, we need to save the user online status to a  global DataTable or  DataBase. In the sample application, define a global DataTable to store the information of online users.Use XmlHttpRequest in the pages to update and check user's last active time at intervals and also retrieve information on how many users are still online. The sample project can auto delete offline users' information from a global DataTable by checking users’ last active time. A step-by-step guide illustrating how to display a list of current online users' information without using membership provider: 1. Login page. Let user sign in and add current user’s information to a global datatable while Initialize the global datatable which used to store information of current online users. 2. Current online user list page. Use XmlHttpRequest in this page to update and check user's last active time at intervals and also retrieve information on how many users are still online. 3. If user closes the page without clicking  the sign out link button ,the sample project can auto mark the user as offline and delete offline users' information from a global DataTable which used to store information of current online users  by checking users’ last active time. Then the current online user list will be like this:   CSASPNETIPtoLocation This sample demonstrates how to find the geographical location from an IP address. As we know, it is not hard for us to get the IP address of visitors via Request.ServerVariable property, but it is really difficult for us to know where they come from. To achieve this feature, the sample uses a free third party web service from http://freegeoip.appspot.com/, which returns the information about an IP address we send to the server in the format of XML, JSON or CSV. It makes all things easier.   CSASPNETBackgroundWorker Sometimes we do an operation which needs long time to complete. It will stop the response and the page is blank until the operation finished. In this case, we want the operation to run in the background, and in the page, we want to display the progress of the running operation. Therefore, the user can know the operation is running and can know the progress. CSASPNETInheritingFromTreeNode In windows forms TreeView, each tree node has a property called "Tag" which can be used to store a custom object. Many customers want to implement the same tag feature in ASP.NET TreeView. This project creates a custom TreeView control named "CustomTreeView" to achieve this goal. CSASPNETRemoteUploadAndDownload and VBASPNETRemoteUploadAndDownload This code sample was created in response to a code sample request in our new code sample request frunction for customers. The code samples demonstrate uploading files to and downloading files from a remote HTTP or FTP server. In .NET Framework 2.0 and higher versions, there are some lightweight class libraries which support HTTP and FTP protocol transmission. By using these classes, we can achieve this programming requirement.   CSASPNETImageEditUpload and VBASPNETImageEditUpload This demo will shows how to insert, edit and update a common image with the type of "jpg", "png", "gif" or "bmp" . We mainly use two different SqlDataSources with the same database to bind to GridView and FormView in order to establish the “cascading” effort. Besides we apply our self-made ImageHanlder to encoding or decoding images of different types, and use context to output the stream of images. We will explicitly assign the binary streams of images through the event of “FormView_ItemInserting” or “Form_ItemUpdating” to synchronize the stream both in what we can see on an aspx page as well as in what’s really stored in the database.   WebBrowser Control, Network and other Windows General New Code Samples   CSWebBrowserSuppressError and VBWebBrowserSuppressError The sample demonstrates how to make WebBrowser suppress errors, such as script error, navigation error and so on.   CSWebBrowserWithProxy and VBWebBrowserWithProxy The sample demonstrates how to make WebBrowser use a proxy server.   CSWebDownloadProgress and VBWebDownloadProgress The sample demonstrates how to show progress during the download. It also supplies the features to Start, Pause, Resume and Cancel a download.   CppSetDesktopWallpaper, CSSetDesktopWallpaper and VBSetDesktopWallpaper This code sample application allows you select an image, view a preview (resized smaller to fit if necessary), select a display style among Tile, Center, Stretch, Fit (Windows 7 and later) and Fill (Windows 7 and later), and set the image as the Desktop wallpaper. CSWindowsServiceRecoveryProperty and VBWindowsServiceRecoveryProperty CSWindowsServiceRecoveryProperty example demonstrates how to use ChangeServiceConfig2 to configure the service "Recovery" properties in C#. This example operates all the options you can see on the service "Recovery" tab, including setting the "Enable actions for stops with errors" option in Windows Vista and later operating systems. This example also include how to grant the shut down privilege to the process, so that we can configure a special option in the "Recovery" tab - "Restart Computer Options...".   New Office Development Code Samples   CSOneNoteRibbonAddIn and VBOneNoteRibbonAddIn The code sample demonstrates a OneNote 2010 COM add-in that implements IDTExtensibility2. The add-in also supports customizing the Ribbon by implementing the IRibbonExtensibility interface. It is a skeleton OneNote add-in that developers can extend it to implement more functions. The code sample was requested by a customer in our code sample request service. We expect that this could help developers in the community.   New Windows Shell Code Samples   CppShellExtPreviewHandler, CSShellExtPreviewHandler and VBShellExtPreviewHandler In the past two months, we released the code samples of Windows Context Menu Handler, Infotip Handler, and Thumbnail Handler. This is the fourth part of the shell extension series: Preview Handler. The code samples demo the C++, C# and VB.NET implementation of a preview handler for a new file type registered with the .recipe extension. Preview handlers are called when an item is selected to show a lightweight, rich, read-only preview of the file's contents in the view's reading pane. This is done without launching the file's associated application. Windows Vista and later operating systems support preview handlers. To be a valid preview handler, several interfaces must be implemented. This includes IPreviewHandler (shobjidl.h); IInitializeWithFile, IInitializeWithStream, or IInitializeWithItem (propsys.h); IObjectWithSite (ocidl.h); and IOleWindow (oleidl.h). There are also optional interfaces, such as IPreviewHandlerVisuals (shobjidl.h), that a preview handler can implement to provide extended support. Windows API Code Pack for Microsoft .NET Framework makes the implementation of these interfaces very easy in .NET. The example preview handler provides previews for .recipe files. The .recipe file type is simply an XML file registered as a unique file name extension. It includes the title of the recipe, its author, difficulty, preparation time, cook time, nutrition information, comments, an embedded preview image, and so on. The preview handler extracts the title, comments, and the embedded image, and display them in a preview window.   In response to many customers' request, we added setup projects in every shell extension samples in this release. Those setup projects allow you to deploy the shell extensions to your end users' machines. ---------- Download address: http://1code.codeplex.com/releases/view/57459#DownloadId=185534 Updated code sample index categorized by technologies: http://1code.codeplex.com/wikipage?title=All-In-One%20Code%20Framework%20Sample%20Catalog (it also allows you to download individual code samples instead of the entire All-In-One Code Framework sample package.) If you have any feedback for us, please email: [email protected]. We look forward to your comments.

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• SQL SERVER – CTRL+SHIFT+] Shortcut to Select Code Between Two Parenthesis

  - by pinaldave

  Every weekend brings creative ideas and accidents brings best unknown secrets in front of us. Just a day while working with complex SQL Server code in SSMS I came across very interesting shortcut which I have never used before and instantly fell in love with it. It is totally possible that you are familiar with this but for me it was the first time and I was surprised that I did know know this short cut so far. Shortcut key is CTRL+SHIFT+]. This key can be very useful when dealing with multiple subqueries, CTE or query with multiple parentheses. When exercised this shortcut key it selects T-SQL code between two parentheses. Let us see the examples to understand the same. In each of the examples I have put the cursor at the position displayed and pressed CTRL+SHIFT+] and it has selected the code between two corresponding parentheses. Cursor position 1 Cursor position 2 Cursor position 3 If you are a developer and have to code with complex queries, you will totally appreciate that this feature can save so much of the time for development. I often remember my experience as a developer when I have lost a lot of hours to just balance parentheses. As I said yesterday I found this shortcut accidently. How many of you were aware of this feature? Is there any other useful feature you would like to share with us? Please leave a comment and if I have not covered it earlier, I will share it due credit on this blog. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology Tagged: SQL Shortcut

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• ASP.NET Connections Fall 2011 Slides and Code

  - by Stephen Walther

  Thanks everyone who came to my talks at ASP.NET Connections in Las Vegas!  There was a definite theme to my talks this year…taking advantage of JavaScript to build a rich presentation layer. I gave the following three talks: JsRender Templates – Originally, I was scheduled to give a talk on jQuery Templates.  However, jQuery Templates has been deprecated and JsRender is the new technology which replaces jQuery Templates. In the talk, I give plenty of code samples of using JsRender.  You can download the slides and code samples RIGHT HERE   HTML5 – In this talk, I focused on the features of HTML5 which are the most interesting to developers building database-driven Web applications. In particular, I discussed Web Sockets,  Web workers, Web Storage, Indexed DB, and the Offline Application Cache. All of these features are supported by Safari, Chrome, and Firefox today and they will be supported by Internet Explorer 10. You can download the slides and code samples RIGHT HERE   Ajax Control Toolkit – My company, Superexpert, is responsible for developing and maintaining the Ajax Control Toolkit. In this talk, I discuss all of the bug fixes and new features which the developers on the Superexpert team have added to the Ajax Control Toolkit over the previous six months. We also had a good discussion of the features which people want in future releases of the Ajax Control Toolkit. The slides and code samples for this talk can be downloaded RIGHT HERE   I had a great time in Las Vegas!  Good questions, friendly audience, and lots of opportunities for me to learn new things!      -- Stephen

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• Is functional intellisense and code browsing more beneficial than the use of dependency injection containers

  - by Gavin Howden

  This question is really based on PHP, but could be valid for other dynamically typed, interpreted languages and specifically the methods of generating code insight and object browsing in development environments. We use PHPStorm, and find intellisense invaluable, but it is provided by some limited static analysis and parsing of doc comments. Obviously this does not lend well to obtaining dependencies through a container, as the IDE has no idea of the type returned, so the developer loses out on a plethora of (in the case of our framework anyway) rich documentation provided through the doc comments. So we start to see stuff like this: $widget = $dic->YieldInstance('WidgetA', $arg1, $arg2, $arg3, $arg4...)); /** * @var $widget WidgetA */ So that code insight works. In effect the comments are tightly bound, but worse they come out of sync when code is modified but not the comments: $widget = $dic->YieldInstance('WidgetB', $arg1, $arg2, $arg3, $arg4...)); /** * @var $widget WidgetA */ Obviously the comment could be improved by referencing a Widget interface, but then we might as well use a factory and avoid the requirement for the extra typing hints in the comments, and dic complexity / boiler plating. Which is more important to the average developer, code insight / intellisense or 'nirvana' decouplement?

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• How to write PowerShell code part 4 (using loop)

  - by ybbest

  In this post, I’d like to show you how to loop through the xml element. I will use the list data deletion script as an example. You can download the script here. 1. To perform the loop, I use foreach in powershell. Here is my xml looks like <?xml version="1.0" encoding="utf-8"?> <Site Url="http://workflowuat/npdmoc"> <Lists> <List Name="YBBEST Collaboration Areas" Type="Document Library"/> <List Name="YBBEST Project" /> <List Name="YBBEST Document"/> </Lists> </Site> 2. Here is the PowerShell to manipulate the xml. Note, you need to get to the $configurationXml.Site.Lists.List variable rather than $configurationXml.Site.Lists foreach ($list in $configurationXml.Site.Lists.List){ AppendLog "Clearing data for $($list.Name) at site $weburl" Yellow if($list.Type -eq "Document Library"){ deleteItemsFromDocumentLibrary -Url $weburl -ListName $list.Name }else{ deleteItemsFromList -Url $weburl -ListName $list.Name } AppendLog "Data in $($list.Name) at $weburl is cleared" Green } How to write PowerShell code part 1 How to write PowerShell code part 2 How to write PowerShell code part 3 How to write PowerShell code part 4

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• How to write PowerShell code part 1 (Using external xml configuration file)

  - by ybbest

  In this post, I will show you how to use external xml file with PowerShell. The advantage for doing so is that you can avoid other people to open up your PowerShell code to make the configuration changes; instead all they need to do is to change the xml file. I will refactor my site creation script as an example; you can download the script here and refactored code here. 1. As you can see below, I hard code all the variables in the script itself. $url = "http://ybbest" $WebsiteName = "Ybbest" $WebsiteDesc = "Ybbest test site" $Template = "STS#0" $PrimaryLogin = "contoso\administrator" $PrimaryDisplay = "administrator" $PrimaryEmail = "[email protected]" $MembersGroup = "$WebsiteName Members" $ViewersGroup = "$WebsiteName Viewers" 2. Next, I will show you how to manipulate xml file using PowerShell. You can use the get-content to grab the content of the file. [xml] $xmlconfigurations=get-content .\SiteCollection.xml 3. Then you can set it to variable (the variable has to be typed [xml] after that you can read the content of the xml content, PowerShell also give you nice IntelliSense by press the Tab key. [xml] $xmlconfigurations=get-content .\SiteCollection.xml $xmlconfigurations.SiteCollection $xmlconfigurations.SiteCollection.SiteName 4. After refactoring my code, I can set the variables using the xml file as below. #Set the parameters $siteInformation=$xmlinput.SiteCollection $url = $siteInformation.URL $siteName = $siteInformation.SiteName $siteDesc = $siteInformation.SiteDescription $Template = $siteInformation.SiteTemplate $PrimaryLogin = $siteInformation.PrimaryLogin $PrimaryDisplay = $siteInformation.PrimaryDisplayName $PrimaryEmail = $siteInformation.PrimaryLoginEmail $MembersGroup = "$WebsiteName Members" $ViewersGroup = "$WebsiteName Viewers"

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• How should I design a correct OO design in case of a Business-logic wide operation

  - by Mithir

  EDIT: Maybe I should ask the question in a different way. in light of ammoQ's comment, I realize that I've done something like suggested which is kind of a fix and it is fine by me. But I still want to learn for the future, so that if I develop new code for operations similar to this, I can design it correctly from the start. So, if I got the following characteristics: The relevant input is composed from data which is connected to several different business objects All the input data is validated and cross-checked Attempts are made in order to insert the data to the DB All this is just a single operation from Business side prospective, meaning all of the cross checking and validations are just side effects. I can't think of any other way but some sort of Operator/Coordinator kind of Object which activates the entire procedure, but then I fall into a Functional-Decomposition kind of code. so is there a better way in doing this? Original Question In our system we have many complex operations which involve many validations and DB activities. One of the main Business functionality could have been designed better. In short, there were no separation of layers, and the code would only work from the scenario in which it was first designed at, and now there were more scenarios (like requests from an API or from other devices) So I had to redesign. I found myself moving all the DB code to objects which acts like Business to DB objects, and I've put all the business logic in an Operator kind of a class, which I've implemented like this: First, I created an object which will hold all the information needed for the operation let's call it InformationObject. Then I created an OperatorObject which will take the InformationObject as a parameter and act on it. The OperatorObject should activate different objects and validate or check for existence or any scenario in which the business logic is compromised and then make the operation according to the information on the InformationObject. So my question is - Is this kind of implementation correct? PS, this Operator only works on a single Business-wise Operation.

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• How to write PowerShell code part 1 (Using external xml configuration file)

  - by ybbest

  In this post, I will show you how to use external xml file with PowerShell. The advantage for doing so is that you can avoid other people to open up your PowerShell code to make the configuration changes; instead all they need to do is to change the xml file. I will refactor my site creation script as an example; you can download the script here and refactored code here. 1. As you can see below, I hard code all the variables in the script itself. $url = "http://ybbest" $WebsiteName = "Ybbest" $WebsiteDesc = "Ybbest test site" $Template = "STS#0" $PrimaryLogin = "contoso\administrator" $PrimaryDisplay = "administrator" $PrimaryEmail = "[email protected]" $MembersGroup = "$WebsiteName Members" $ViewersGroup = "$WebsiteName Viewers" 2. Next, I will show you how to manipulate xml file using PowerShell. You can use the get-content to grab the content of the file. [xml] $xmlconfigurations=get-content .\SiteCollection.xml 3. Then you can set it to variable (the variable has to be typed [xml] after that you can read the content of the xml content, PowerShell also give you nice IntelliSense by press the Tab key. [xml] $xmlconfigurations=get-content .\SiteCollection.xml $xmlconfigurations.SiteCollection $xmlconfigurations.SiteCollection.SiteName 4. After refactoring my code, I can set the variables using the xml file as below. #Set the parameters $siteInformation=$xmlinput.SiteCollection $url = $siteInformation.URL $siteName = $siteInformation.SiteName $siteDesc = $siteInformation.SiteDescription $Template = $siteInformation.SiteTemplate $PrimaryLogin = $siteInformation.PrimaryLogin $PrimaryDisplay = $siteInformation.PrimaryDisplayName $PrimaryEmail = $siteInformation.PrimaryLoginEmail $MembersGroup = "$WebsiteName Members" $ViewersGroup = "$WebsiteName Viewers"

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• DDD East Anglia, 29th June 2013 - Async Patterns presentation and source code

  - by Liam Westley

  Originally posted on: http://geekswithblogs.net/twickers/archive/2013/07/01/ddd-east-anglia-29th-june-2013---async-patterns-presentation.aspxMany thanks to the team in Cambridge for an awesome first conference DDD East Anglia.  I definitely appreciate how each of the different areas have their own distinctive atmosphere and feel.  Thanks to some great sponsors we enjoyed a great venue and some excellent nibbles. For those who attended my Async my source code and presentation are available on GitHub, https://github.com/westleyl/DDDEastAnglia2013-Async.git If you are new to Git then the easiest client to install is GitHub for Windows, a graphical UI for accessing GitHub. Personally, I also have Git Extensions and Tortoise Git installed. Tortoise Git is the file explorer add-in that works in a familiar manner to TortoiseSVN. As I mentioned during the presentation I have not included the sample data, the music files, in the source code placed on GitHub but I have included instructions on how to download them from http://silents.bandcamp.comand place them in the correct folders. Also, Windows Media Player, by default, does not play Ogg Vorbis and Flac music files, however you can download the codec installer for these, for free, from http://xiph.org/dshow. I have included the .Net 4.0 version of the source code that uses the Microsoft.Bcl.Async NuGet package - once you have got the project from GitHub you will need to install this NuGet package for the code to compile. Load Project into Visual Studio 2012 Access the NuGet package manager (Tools -> Library Package Manager -> Manage NuGet Packages For Solution) Highlight Online and then Search Online for microsoft.bcl.async Click on Install button Resources : You can download the Task-based Asynchronous Pattern white paper by Stephen Toub, which was the inspiration for this presentation from here - http://www.microsoft.com/en-us/download/details.aspx?id=19957 Presentation : If you just want the presentation and don’t want to bother with a GitHub login you can download the PowerPoint presentation from here.

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• Carolina Code Camp 2010

  - by Mark A. Wilson

  "Grow your skills in 2010" The Enterprise Developers Guild in Charlotte, the Greenville-Spartanburg Enterprise Developers Guild and the Triad Developers Guild have joined with Microsoft and Central Piedmont Community College (CPCC) Association for Computing Machinery (ACM) to present the 10th MSDN Code Camp to be held in Charlotte. Please join me and fellow developers and code enthusiasts on Saturday, May 15, 2010, at the CPCC Levine Campus in Matthews, NC. The focus this year is Microsoft Visual Studio 2010 and Windows Phone 7. Everyone is invited to attend and/or speak! Get in-depth exposure to Visual Studio 2010 and other exciting new Microsoft technologies. Sessions will range from presentations, to hands on labs, to informal "chalk talks". We will have a mix of speakers including Microsoft MVPs, authors, and most importantly, local developers just like you! And thanks to the generosity of our contributors, we will be able to provide breakfast, lunch, snacks, and lots of swag. Registration is open and there are a limited number of seats left. For more information or to register, visit the Carolina Code Camp 2010 event website. I encourage you to "give back" by registering as a volunteer or a proctor. This will be the only Carolina Code Camp held this year – no event is schedule for the fall – so register today before it’s too late! Thanks for visiting and till next time, Mark A. Wilson      Mark's Geekswithblogs Blog Enterprise Developers Guild Technorati Tags: Community

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• ASP.NET Connections Spring 2012 Talks and Code

  - by Stephen.Walther

  Thank you everyone who attended my ASP.NET Connections talks last week in Las Vegas. I’ve attached the slides and code for the three talks that I delivered:   Using jQuery to interact with the Server through Ajax – In this talk, I discuss the different ways to communicate information between browser and server using Ajax. I explain the difference between the different types of Ajax calls that you can make with jQuery. I also discuss the differences between the JavaScriptSerializer, the DataContractJsonSerializer, and the JSON.NET serializer.   ASP.NET Validation In-Depth – In this talk, I distinguish between View Model Validation and Domain Model Validation. I demonstrate how you can use the validation attributes (including the new .NET 4.5 validation attributes), the jQuery Validation library, and the HTML5 input validation attributes to perform View Model Validation. I then demonstrate how you can use the IValidatableObject interface with the Entity Framework to perform Domain Model Validation.   Using the MVVM Pattern with JavaScript Views – In this talk, I discuss how you can create single page applications (SPA) by taking advantage of the open-source KnockoutJS library and the ASP.NET Web API.   Be warned that the sample code is contained in Visual Studio 11 Beta projects. If you don’t have this version of Visual Studio, then you will need to open the code samples in Notepad. Also, I apologize for getting the code for these talks posted so slowly. I’ve been down with a nasty case of the flu for the past week and haven’t been able to get to a computer.

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• How to evaluate the quality of Rails code?

  - by Fortuity

  In a code review, what do you look for to assess a developer's expertise? Given an opportunity to look at a developer's work on a real-world project, what tell-tale signs are a tip-off to carelessness or lack of experience? Conversely, where do you look in the code to find evidence of a developer's skill or knowledge of best practices? For example, if I'm looking at a typical Rails app, I would be happy to see the developer is using RSpec (showing a commitment to using test-driven development and knowledge that RSpec is currently more popular than the default TestUnit). But in examining the specs for a Rails model, I see that the developer is testing associations, which might indicate a lack of real understanding of Rails testing requirements (since such tests are redundant given that they only test what's already implemented and tested in ActiveRecord). More generally, I might look to see if developers are writing their own implementations versus using widely available gems or if they are cleaning up code versus leaving lots of commented-out "leftovers." What helps you determine the skill of a Rails developer? What's your code quality checklist?

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• ASP.NET Connections Spring 2012 Talks and Code

  - by Stephen.Walther

  Thank you everyone who attended my ASP.NET Connections talks last week in Las Vegas. I’ve attached the slides and code for the three talks that I delivered: Using jQuery to interact with the Server through Ajax– In this talk, I discuss the different ways to communicate information between browser and server using Ajax. I explain the difference between the different types of Ajax calls that you can make with jQuery. I also discuss the differences between the JavaScriptSerializer, the DataContractJsonSerializer, and the JSON.NET serializer. ASP.NET Validation In-Depth– In this talk, I distinguish between View Model Validation and Domain Model Validation. I demonstrate how you can use the validation attributes (including the new .NET 4.5 validation attributes), the jQuery Validation library, and the HTML5 input validation attributes to perform View Model Validation. I then demonstrate how you can use the IValidatableObject interface with the Entity Framework to perform Domain Model Validation. Using the MVVM Pattern with JavaScript Views – In this talk, I discuss how you can create single page applications (SPA) by taking advantage of the open-source KnockoutJS library and the ASP.NET Web API. Be warned that the sample code is contained in Visual Studio 11 Beta projects. If you don’t have this version of Visual Studio, then you will need to open the code samples in Notepad. Also, I apologize for getting the code for these talks posted so slowly. I’ve been down with a nasty case of the flu for the past week and haven’t been able to get to a computer.

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• Building a common syntax and scoping framework.

  - by Ben DeMott

  Hello fellow programmers, I was discussing a project the other day with a colleague of mine and I was curious to see what others had to say or if such a thing already existed. Background There are many programming languages. There are many IDE's and source editors that highlight and edit source code. Following perfectly and exactly the rules of a language to present auto-complete options and understand scopes in the code is rather complex. This task is complex enough that most IDE's implement different source-editors as plugins that often re-implement the same features over and over but in a different way (netbeans). From what I can tell most IDE's and source editors re-implement parsers that use regular expressions, or some meta-syntax Naur Form to describe the languages grammer generically. These parsers are implemented over and over and over again. Question Has anyone attempted to unify or describe a set of features through an API and have a consistent interface to parsing various programming languages and dialects. I'm not describing an IDE - but a consistent API for any program to use to parse and obtain meta-information from the source code. I realize various programming languages offer many different features which are difficult to 'abstract' into a set of features, but I feel this would be a worthwhile venture. It seems to me that this could possibly allow the authors of interpreters to help maintain a central grammer intepreter for their language. the Python foundation could maintain the Python grammer api, ANSI the C grammer api, Oracle the Java grammer API, etc Example usage If this was API existed code documentation generators could theoretically work across all dialects and languages to some level. It wouldn't matter if your project used 5 different languages a single application could document all of them and the comments and doc-tags within. Has anyone attempted this comprehensively?

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• On the frontier between work and home

  - by MPelletier

  I think we've all been there: You hear of someone say "hey, wouldn't it be nice if platform X had feature Y?" You look around (on SO!), the feature really doesn't exist, even though it probably would be useful in many contexts. So it's pretty generic. Your mind wanders for a bit. "How tough would it be? Well, it'd probably be just a snippet. And an ad-hoc function. And maybe a wrapper." And boom, before you know it, you've spent a dozen hours of your free time implementing a FooFeature that's really neat and generic. The kind of code you might not even have the time to spit and shine at work, that would be a bit rushed and not so documented. So now you wonder "wouldn't this be useful to others?" And you've got your blog, maybe a CodeProject account, and your colleague who asked if FooFeature exists might, haphazardly, come accross that blog entry, had it existed before they told you. On the otherhand, the NDA agreement. It's sort of vague and general. It doesn't forbid you from coding at home, but it's clear on sharing company code, that's a big NO. But this isn't company code. Or is it? Or will it be? So, what do you do with code (that's more than just a snippet) you wrote in your off time with universality in mind but an idea that came from work, and that will most likely be used at work? Can it be published?

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• Releasing an open source project without getting embarrassed

  - by Hopeful

  I've been working by myself on a fairly large open source project for quite a while and it's nearing the point where I'd like to release it. However, I'm self-taught and I don't really know anyone who could adequately review my project. A few years ago, I had released a small bit of code which pretty much got ripped apart (in a critical sense) on the forum where I released it. Even though the code worked, the criticism was accurate but brutal. It prompted me to begin searching for best practices for everything and in the end I feel that it made me a much better developer. I've gone over everything in my project so many times trying to make it perfect that I've lost count. I believe in my project and think it has the potential to help a lot of people and I feel like I've done some cool things in interesting ways with it. Still, because I'm self-taught, I can't help but wonder what gaps exist in my self-education. The way my code was ripped apart last time isn't something I'd like to repeat. I think my two biggest fears with releasing my project that I've poured countless hours into are being absolutely embarrassed because I missed some patently obvious things because of my self-education or, worse, releasing it to the sound of crickets. Is there anyone who has been in a similar situation? I'm not afraid of constructive criticism, so long as it is constructive and not just a rant on how I screwed up. I know there is a code review site on StackExchange, but it's not really set up for large projects and I didn't feel like the community there is large enough yet to get good feedback if I were to post parts of my project piecemeal (I tried with one file). What can I do to give my project at least some measure of success without getting embarrassed or devestated in the process?

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• EF4 CPT5 Code First Remove Cascading Deletes

  - by Dane Morgridge

  I have been using EF4 CTP5 with code first and I really like the new code.  One issue I was having however, was cascading deletes is on by default.  This may come as a surprise as using Entity Framework with anything but code first, this is not the case.  I ran into an exception with some one-to-many relationships I had: Introducing FOREIGN KEY constraint 'ProjectAuthorization_UserProfile' on table 'ProjectAuthorizations' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint. See previous errors. To get around this, you can use the fluent API and put some code in the OnModelCreating: 1: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) 2: { 3: modelBuilder.Entity<UserProfile>() 4: .HasMany(u => u.ProjectAuthorizations) 5: .WithRequired(a => a.UserProfile) 6: .WillCascadeOnDelete(false); 7: } This will work to remove the cascading delete, but I have to use the fluent API and it has to be done for every one-to-many relationship that causes the problem. I am personally not a fan of cascading deletes in general (for several reasons) and I’m not a huge fan of fluent APIs.  However, there is a way to do this without using the fluent API.  You can in the OnModelCreating, remove the convention that creates the cascading deletes altogether. 1: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) 2: { 3: modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>(); 4: } Thanks to Jeff Derstadt from Microsoft for the info on removing the convention all together.  There is a way to build a custom attribute to remove it on a case by case basis and I’ll have a post on how to do this in the near future.

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• How to learn the math behind the code?

  - by Solomon Wise

  I am a 12 year old who has recently gotten into programming. (Although I know that the number of books you have read does not determine your programming competency or ability, just to paint a "map" of where I am in terms of the content I know...) I've finished the books: Python 3 For Absolute Beginners Pro Python Python Standard Library by Example Beautiful Code Agile Web Development With Rails and am about halfway into Programming Ruby. I have written many small programs (One that finds which files have been updated and deleted in a directory, one that compares multiple players' fantasy baseball value, and some text based games, and many more). Obviously, as I'm not some sort of child prodigy, I can't take a formal Computer Science course until high school. I really want to learn computer science to increase my knowledge about the code, and the how the code runs. I've really become interested in the math part after reading the source code for Python's random module. Is there a place where I can learn CS, or programming math online for free, at a level that would be at least partially understandable to a person my age?

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• Effective versus efficient code

  - by Todd Williamson

  TL;DR: Quick and dirty code, or "correct" (insert your definition of this term) code? There is often a tension between "efficient" and "effective" in software development. "Efficient" often means code that is "correct" from the point of view of adhering to standards, using widely-accepted patterns/approaches for structures, regardless of project size, budget, etc. "Effective" is not about being "right", but about getting things done. This often results in code that falls outside the bounds of commonly accepted "correct" standards, usage, etc. Usually the people paying for the development effort have dictated ahead of time what it is that they value more. An organization that lives in a technical space will tend towards the efficient end, others will tend towards the effective. Developers often refuse to compromise their favored approach for the other. In my own experience I have found that people with formal education in software development tend towards the Efficient camp. Those that picked up software development more or less as a tool to get things done tend towards the Effective camp. These camps don't get along very well. When managing a team of developers who are not all in one camp it is challenging. In your own experience, which camp do you land in, and do you find yourself having to justify your approach to others? To management? To other developers?

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• Interpreting Others' Source Code

  - by Maxpm

  Note: I am aware of this question. This question is a bit more specific and in-depth, however, focusing on reading the actual code rather than debugging it or asking the author. As a student in an introductory-level computer science class, my friends occasionally ask me to help them with their assignments. Programming is something I'm very proud of, so I'm always happy to oblige. However, I usually have difficulty interpreting their source code. Sometimes this is due to a strange or inconsistent style, sometimes it's due to strange design requirements specified in the assignment, and sometimes it's just due to my stupidity. In any case, I end up looking like an idiot staring at the screen for several minutes saying "Uh..." I usually check for the common errors first - missing semicolons or parentheses, using commas instead of extractor operators, etc. The trouble comes when that fails. I often can't step through with a debugger because it's a syntax error, and I often can't ask the author because he/she him/herself doesn't understand the design decisions. How do you typically read the source code of others? Do you read through the code from top-down, or do you follow each function as it's called? How do you know when to say "It's time to refactor?"

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• Evaluating code for a graph [migrated]

  - by mazen.r.f

  This is relatively long code. Please take a look at this code if you are still willing to do so. I will appreciate your feedback. I have spent two days trying to come up with code to represent a graph, calculating the shortest path using Dijkstra's algorithm. But I am not able to get the right result, even though the code runs without errors. The result is not correct and I am always getting 0. I have three classes: Vertex, Edge, and Graph. The Vertex class represents the nodes in the graph and it has id and carried (which carry the weight of the links connected to it while using Dijkstra's algorithm) and a vector of the ids belong to other nodes the path will go through before arriving to the node itself. This vector is named previous_nodes. The Edge class represents the edges in the graph and has two vertices (one in each side) and a width (the distance between the two vertices). The Graph class represents the graph. It has two vectors, where one is the vertices included in this graph, and the other is the edges included in the graph. Inside the class Graph, there is a method named shortest() that takes the sources node id and the destination and calculates the shortest path using Dijkstra's algorithm. I think that it is the most important part of the code. My theory about the code is that I will create two vectors, one for the vertices in the graph named vertices, and another vector named ver_out (it will include the vertices out of calculation in the graph). I will also have two vectors of type Edge, where one is named edges (for all the edges in the graph), and the other is named track (to temporarily contain the edges linked to the temporary source node in every round). After the calculation of every round, the vector track will be cleared. In main(), I've created five vertices and 10 edges to simulate a graph. The result of the shortest path supposedly is 4, but I am always getting 0. That means I have something wrong in my code. If you are interesting in helping me find my mistake and making the code work, please take a look. The way shortest work is as follow: at the beginning, all the edges will be included in the vector edges. We select the edges related to the source and put them in the vector track, then we iterate through track and add the width of every edge to the vertex (node) related to it (not the source vertex). After that, we clear track and remove the source vertex from the vector vertices and select a new source. Then we start over again and select the edges related to the new source, put them in track, iterate over edges in track, adding the weights to the corresponding vertices, then remove this vertex from the vector vertices. Then clear track, and select a new source, and so on. #include<iostream> #include<vector> #include <stdlib.h> // for rand() using namespace std; class Vertex { private: unsigned int id; // the name of the vertex unsigned int carried; // the weight a vertex may carry when calculating shortest path vector<unsigned int> previous_nodes; public: unsigned int get_id(){return id;}; unsigned int get_carried(){return carried;}; void set_id(unsigned int value) {id = value;}; void set_carried(unsigned int value) {carried = value;}; void previous_nodes_update(unsigned int val){previous_nodes.push_back(val);}; void previous_nodes_erase(unsigned int val){previous_nodes.erase(previous_nodes.begin() + val);}; Vertex(unsigned int init_val = 0, unsigned int init_carried = 0) :id (init_val), carried(init_carried) // constructor { } ~Vertex() {}; // destructor }; class Edge { private: Vertex first_vertex; // a vertex on one side of the edge Vertex second_vertex; // a vertex on the other side of the edge unsigned int weight; // the value of the edge ( or its weight ) public: unsigned int get_weight() {return weight;}; void set_weight(unsigned int value) {weight = value;}; Vertex get_ver_1(){return first_vertex;}; Vertex get_ver_2(){return second_vertex;}; void set_first_vertex(Vertex v1) {first_vertex = v1;}; void set_second_vertex(Vertex v2) {second_vertex = v2;}; Edge(const Vertex& vertex_1 = 0, const Vertex& vertex_2 = 0, unsigned int init_weight = 0) : first_vertex(vertex_1), second_vertex(vertex_2), weight(init_weight) { } ~Edge() {} ; // destructor }; class Graph { private: std::vector<Vertex> vertices; std::vector<Edge> edges; public: Graph(vector<Vertex> ver_vector, vector<Edge> edg_vector) : vertices(ver_vector), edges(edg_vector) { } ~Graph() {}; vector<Vertex> get_vertices(){return vertices;}; vector<Edge> get_edges(){return edges;}; void set_vertices(vector<Vertex> vector_value) {vertices = vector_value;}; void set_edges(vector<Edge> vector_ed_value) {edges = vector_ed_value;}; unsigned int shortest(unsigned int src, unsigned int dis) { vector<Vertex> ver_out; vector<Edge> track; for(unsigned int i = 0; i < edges.size(); ++i) { if((edges[i].get_ver_1().get_id() == vertices[src].get_id()) || (edges[i].get_ver_2().get_id() == vertices[src].get_id())) { track.push_back (edges[i]); edges.erase(edges.begin()+i); } }; for(unsigned int i = 0; i < track.size(); ++i) { if(track[i].get_ver_1().get_id() != vertices[src].get_id()) { track[i].get_ver_1().set_carried((track[i].get_weight()) + track[i].get_ver_2().get_carried()); track[i].get_ver_1().previous_nodes_update(vertices[src].get_id()); } else { track[i].get_ver_2().set_carried((track[i].get_weight()) + track[i].get_ver_1().get_carried()); track[i].get_ver_2().previous_nodes_update(vertices[src].get_id()); } } for(unsigned int i = 0; i < vertices.size(); ++i) if(vertices[i].get_id() == src) vertices.erase(vertices.begin() + i); // removing the sources vertex from the vertices vector ver_out.push_back (vertices[src]); track.clear(); if(vertices[0].get_id() != dis) {src = vertices[0].get_id();} else {src = vertices[1].get_id();} for(unsigned int i = 0; i < vertices.size(); ++i) if((vertices[i].get_carried() < vertices[src].get_carried()) && (vertices[i].get_id() != dis)) src = vertices[i].get_id(); //while(!edges.empty()) for(unsigned int round = 0; round < vertices.size(); ++round) { for(unsigned int k = 0; k < edges.size(); ++k) { if((edges[k].get_ver_1().get_id() == vertices[src].get_id()) || (edges[k].get_ver_2().get_id() == vertices[src].get_id())) { track.push_back (edges[k]); edges.erase(edges.begin()+k); } }; for(unsigned int n = 0; n < track.size(); ++n) if((track[n].get_ver_1().get_id() != vertices[src].get_id()) && (track[n].get_ver_1().get_carried() > (track[n].get_ver_2().get_carried() + track[n].get_weight()))) { track[n].get_ver_1().set_carried((track[n].get_weight()) + track[n].get_ver_2().get_carried()); track[n].get_ver_1().previous_nodes_update(vertices[src].get_id()); } else if(track[n].get_ver_2().get_carried() > (track[n].get_ver_1().get_carried() + track[n].get_weight())) { track[n].get_ver_2().set_carried((track[n].get_weight()) + track[n].get_ver_1().get_carried()); track[n].get_ver_2().previous_nodes_update(vertices[src].get_id()); } for(unsigned int t = 0; t < vertices.size(); ++t) if(vertices[t].get_id() == src) vertices.erase(vertices.begin() + t); track.clear(); if(vertices[0].get_id() != dis) {src = vertices[0].get_id();} else {src = vertices[1].get_id();} for(unsigned int tt = 0; tt < edges.size(); ++tt) { if(vertices[tt].get_carried() < vertices[src].get_carried()) { src = vertices[tt].get_id(); } } } return vertices[dis].get_carried(); } }; int main() { cout<< "Hello, This is a graph"<< endl; vector<Vertex> vers(5); vers[0].set_id(0); vers[1].set_id(1); vers[2].set_id(2); vers[3].set_id(3); vers[4].set_id(4); vector<Edge> eds(10); eds[0].set_first_vertex(vers[0]); eds[0].set_second_vertex(vers[1]); eds[0].set_weight(5); eds[1].set_first_vertex(vers[0]); eds[1].set_second_vertex(vers[2]); eds[1].set_weight(9); eds[2].set_first_vertex(vers[0]); eds[2].set_second_vertex(vers[3]); eds[2].set_weight(4); eds[3].set_first_vertex(vers[0]); eds[3].set_second_vertex(vers[4]); eds[3].set_weight(6); eds[4].set_first_vertex(vers[1]); eds[4].set_second_vertex(vers[2]); eds[4].set_weight(2); eds[5].set_first_vertex(vers[1]); eds[5].set_second_vertex(vers[3]); eds[5].set_weight(5); eds[6].set_first_vertex(vers[1]); eds[6].set_second_vertex(vers[4]); eds[6].set_weight(7); eds[7].set_first_vertex(vers[2]); eds[7].set_second_vertex(vers[3]); eds[7].set_weight(1); eds[8].set_first_vertex(vers[2]); eds[8].set_second_vertex(vers[4]); eds[8].set_weight(8); eds[9].set_first_vertex(vers[3]); eds[9].set_second_vertex(vers[4]); eds[9].set_weight(3); unsigned int path; Graph graf(vers, eds); path = graf.shortest(2, 4); cout<< path << endl; return 0; }

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