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  • Is writing recursive functions hard for you?

    - by null
    I'm taking a computer science course now. I feel it is so hard compared to my polytechnic IT course. I can't understand recursive methods well. How do you manage to get your brain to understand it? When the recursive method returns back, my brain can not trace it nicely. Is there a better way to understand recursion? How do you start learning it? Is it normal that feel that it is very hard at then beginning? Look at the example, I'm very surprised how can I write this if it appears in exam. public class Permute { public static void main(String[] args) { new Permute().printPerms(3); } boolean[] used; int max; public void printPerms(int size) { used = new boolean[size]; max = size; for (int i = 0; i < size; i++) { used[i] = false; } perms(size, ""); } public void perms(int remaining, String res) { if (remaining == 0) { System.out.println(res); } else { for (int i = 0; i < max; i++) { if (!(used[i])) { used[i] = true; perms(remaining - 1, res + " " + i); used[i] = false; } } } } }

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  • I want to make "stuff" on the web, is a BsC. in Computers necessary/overkill? [on hold]

    - by notypist
    I'm 24 and have a lead role in a major news outlet in my country, with a good pay and public image in the horizon. I hold a job that was previously held by people with 15-20 years of experience and considered one of the top 5 news anchors in my country. My passion though, is computers. The web, to be precise. I was a problogger at a very young age. I hacked my way through CSS and some basic HTML and PHP. But I want to move forward - I want to CREATE not just STRUCTURE things. Giving up the present (and especially the seemingly promising future) in my current industry is hard, my friends raise their eyebrows... I'm considering a BsC. in computer Engineering - but my stats are short of getting into a good university for this discipline. Plus, I'm not the best with math - although I do exceptionally well in statistics and other numbers that are more applicable to real life. I tried learning PHP through online websites, but that just "doesn't cut it" for me. Nope. So what are my options here? if I don't want to build hardware or and deal with overly-complex algorithmic but would like, for example - to build a well functioning iPhone and iPad app, or a SaaS, a startup...do I have to go the BsC. route? I don't see any option to get an "official" education in strictly "web" concepts and languages.. Note: I'm well off financially, so I'm doing this more to be able to create stuff, rather than get a job in a corporations. Although if I land somewhere high, that might be an option. But my main concern is getting the tools.

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  • Localization in ASP.NET MVC 2 using ModelMetadata

    - by rajbk
    This post uses an MVC 2 RTM application inside VS 2010 that is targeting the .NET Framework 4. .NET 4 DataAnnotations comes with a new Display attribute that has several properties including specifying the value that is used for display in the UI and a ResourceType. Unfortunately, this attribute is new and is not supported in MVC 2 RTM. The good news is it will be supported and is currently available in the MVC Futures release. The steps to get this working are shown below: Download the MVC futures library   Add a reference to the Microsoft.Web.MVC.AspNet4 dll.   Add a folder in your MVC project where you will store the resx files   Open the resx file and change “Access Modifier” to “Public”. This allows the resources to accessible from other assemblies. Internaly, it changes the “Custom Tool” used to generate the code behind from  ResXFileCodeGenerator to “PublicResXFileCodeGenerator”    Add your localized strings in the resx.   Register the new ModelMetadataProvider protected void Application_Start() { AreaRegistration.RegisterAllAreas();   RegisterRoutes(RouteTable.Routes);   //Add this ModelMetadataProviders.Current = new DataAnnotations4ModelMetadataProvider(); DataAnnotations4ModelValidatorProvider.RegisterProvider(); }   Use the Display attribute in your Model public class Employee { [Display(Name="ID")] public int ID { get; set; }   [Display(ResourceType = typeof(Common), Name="Name")] public string Name { get; set; } } Use the new HTML UI Helpers in your strongly typed view: <%: Html.EditorForModel() %> <%: Html.EditorFor(m => m) %> <%: Html.LabelFor(m => m.Name) %> ..and you are good to go. Adventure is out there!

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  • Visual Studio 2013, ASP.NET MVC 5 Scaffolded Controls, and Bootstrap

    - by plitwin
    A few days ago, I created an ASP.NET MVC 5 project in the brand new Visual Studio 2013. I added some model classes and then proceeded to scaffold a controller class and views using the Entity Framework. Scaffolding Some Views Visual Studio 2013, by default, uses the Bootstrap 3 responsive CSS framework. Great; after all, we all want our web sites to be responsive and work well on mobile devices. Here’s an example of a scaffolded Create view as shown in Google Chrome browser   Looks pretty good. Okay, so let’s increase the width of the Title, Description, Address, and Date/Time textboxes. And decrease the width of the  State and MaxActors textbox controls. Can’t be that hard… Digging Into the Code Let’s take a look at the scaffolded Create.cshtml file. Here’s a snippet of code behind the Create view. Pretty simple stuff. @using (Html.BeginForm()) { @Html.AntiForgeryToken() <div class="form-horizontal"> <h4>RandomAct</h4> <hr /> @Html.ValidationSummary(true) <div class="form-group"> @Html.LabelFor(model => model.Title, new { @class = "control-label col-md-2" }) <div class="col-md-10"> @Html.EditorFor(model => model.Title) @Html.ValidationMessageFor(model => model.Title) </div> </div> <div class="form-group"> @Html.LabelFor(model => model.Description, new { @class = "control-label col-md-2" }) <div class="col-md-10"> @Html.EditorFor(model => model.Description) @Html.ValidationMessageFor(model => model.Description) </div> </div> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } A little more digging and I discover that there are three CSS files of importance in how the page is rendered: boostrap.css (and its minimized cohort) and site.css as shown below.   The Root of the Problem And here’s the root of the problem which you’ll find the following CSS in Site.css: /* Set width on the form input elements since they're 100% wide by default */ input, select, textarea { max-width: 280px; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Yes, Microsoft is for some reason setting the maximum width of all input, select, and textarea controls to 280 pixels. Not sure the motivation behind this, but until you change this or overrride this by assigning the form controls to some other CSS class, your controls will never be able to be wider than 280px. The Fix Okay, so here’s the deal: I hope to become very competent in all things Bootstrap in the near future, but I don’t think you should have to become a Bootstrap guru in order to modify some scaffolded control widths. And you don’t. Here is the solution I came up with: Find the aforementioned CSS code in SIte.css and change it to something more tenable. Such as: /* Set width on the form input elements since they're 100% wide by default */ input, select, textarea { max-width: 600px; } Because the @Html.EditorFor html helper doesn’t support the passing of HTML attributes, you will need to repalce any @Html.EditorFor() helpers with @Html.TextboxFor(), @Html.TextAreaFor, @Html.CheckBoxFor, etc. helpers, and then add a custom width attribute to each control you wish to modify. Thus, the earlier stretch of code might end up looking like this: @using (Html.BeginForm()) { @Html.AntiForgeryToken() <div class="form-horizontal"> <h4>Random Act</h4> <hr /> @Html.ValidationSummary(true) <div class="form-group"> @Html.LabelFor(model => model.Title, new { @class = "control-label col-md-2" }) <div class="col-md-10"> @Html.TextBoxFor(model => model.Title, new { style = "width: 400px" }) @Html.ValidationMessageFor(model => model.Title) </div> </div> <div class="form-group"> @Html.LabelFor(model => model.Description, new { @class = "control-label col-md-2" }) <div class="col-md-10"> @Html.TextAreaFor(model => model.Description, new { style = "width: 400px" }) @Html.ValidationMessageFor(model => model.Description) </div> </div> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Resulting Form Here’s what the page looks like after the fix: Technorati Tags: ASP.NET MVC,ASP.NET MVC 5,Bootstrap

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  • NoSQL with RavenDB and ASP.NET MVC - Part 2

    - by shiju
    In my previous post, we have discussed on how to work with RavenDB document database in an ASP.NET MVC application. We have setup RavenDB for our ASP.NET MVC application and did basic CRUD operations against a simple domain entity. In this post, let’s discuss on domain entity with deep object graph and how to query against RavenDB documents using Indexes.Let's create two domain entities for our demo ASP.NET MVC appplication  public class Category {       public string Id { 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 List<Expense> Expenses { get; set; }       public Category()     {         Expenses = new List<Expense>();     } }    public class Expense {       public string Id { get; set; }     public Category Category { get; set; }     public string  Transaction { get; set; }     public DateTime Date { get; set; }     public double Amount { 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.Let's create  ASP.NET MVC view model  for Expense transaction public class ExpenseViewModel {     public string Id { get; set; }       public string 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; } } Let's create a contract type for Expense Repository  public interface IExpenseRepository {     Expense Load(string id);     IEnumerable<Expense> GetExpenseTransactions(DateTime startDate,DateTime endDate);     void Save(Expense expense,string categoryId);     void Delete(string id);  } Let's create a concrete type for Expense Repository for handling CRUD operations. public class ExpenseRepository : IExpenseRepository {   private IDocumentSession session; public ExpenseRepository() {         session = MvcApplication.CurrentSession; } public Expense Load(string id) {     return session.Load<Expense>(id); } public IEnumerable<Expense> GetExpenseTransactions(DateTime startDate, DateTime endDate) {             //Querying using the Index name "ExpenseTransactions"     //filtering with dates     var expenses = session.LuceneQuery<Expense>("ExpenseTransactions")         .WaitForNonStaleResults()         .Where(exp => exp.Date >= startDate && exp.Date <= endDate)         .ToArray();     return expenses; } public void Save(Expense expense,string categoryId) {     var category = session.Load<Category>(categoryId);     if (string.IsNullOrEmpty(expense.Id))     {         //new expense transaction         expense.Category = category;         session.Store(expense);     }     else     {         //modifying an existing expense transaction         var expenseToEdit = Load(expense.Id);         //Copy values to  expenseToEdit         ModelCopier.CopyModel(expense, expenseToEdit);         //set category object         expenseToEdit.Category = category;       }     //save changes     session.SaveChanges(); } public void Delete(string id) {     var expense = Load(id);     session.Delete<Expense>(expense);     session.SaveChanges(); }   }  Insert/Update Expense Transaction The Save method is used for both insert a new expense record and modifying an existing expense transaction. For a new expense transaction, we store the expense object with associated category into document session object and load the existing expense object and assign values to it for editing a existing record.  public void Save(Expense expense,string categoryId) {     var category = session.Load<Category>(categoryId);     if (string.IsNullOrEmpty(expense.Id))     {         //new expense transaction         expense.Category = category;         session.Store(expense);     }     else     {         //modifying an existing expense transaction         var expenseToEdit = Load(expense.Id);         //Copy values to  expenseToEdit         ModelCopier.CopyModel(expense, expenseToEdit);         //set category object         expenseToEdit.Category = category;       }     //save changes     session.SaveChanges(); } Querying Expense transactions   public IEnumerable<Expense> GetExpenseTransactions(DateTime startDate, DateTime endDate) {             //Querying using the Index name "ExpenseTransactions"     //filtering with dates     var expenses = session.LuceneQuery<Expense>("ExpenseTransactions")         .WaitForNonStaleResults()         .Where(exp => exp.Date >= startDate && exp.Date <= endDate)         .ToArray();     return expenses; }  The GetExpenseTransactions method returns expense transactions using a LINQ query expression with a Date comparison filter. The Lucene Query is using a index named "ExpenseTransactions" for getting the result set. In RavenDB, Indexes are LINQ queries stored in the RavenDB server and would be  executed on the background and will perform query against the JSON documents. Indexes will be working with a lucene query expression or a set operation. Indexes are composed using a Map and Reduce function. Check out Ayende's blog post on Map/Reduce We can create index using RavenDB web admin tool as well as programmitically using its Client API. The below shows the screen shot of creating index using web admin tool. We can also create Indexes using Raven Cleint API as shown in the following code documentStore.DatabaseCommands.PutIndex("ExpenseTransactions",     new IndexDefinition<Expense,Expense>() {     Map = Expenses => from exp in Expenses                     select new { exp.Date } });  In the Map function, we used a Linq expression as shown in the following from exp in docs.Expensesselect new { exp.Date };We have not used a Reduce function for the above index. A Reduce function is useful while performing aggregate functions based on the results from the Map function. Indexes can be use with set operations of RavenDB.SET OperationsUnlike other document databases, RavenDB supports set based operations that lets you to perform updates, deletes and inserts to the bulk_docs endpoint of RavenDB. For doing this, you just pass a query to a Index as shown in the following commandDELETE http://localhost:8080/bulk_docs/ExpenseTransactions?query=Date:20100531The above command using the Index named "ExpenseTransactions" for querying the documents with Date filter and  will delete all the documents that match the query criteria. The above command is equivalent of the following queryDELETE FROM ExpensesWHERE Date='2010-05-31' Controller & ActionsWe have created Expense Repository class for performing CRUD operations for the Expense transactions. Let's create a controller class for handling expense transactions.   public class ExpenseController : Controller { private ICategoryRepository categoyRepository; private IExpenseRepository expenseRepository; public ExpenseController(ICategoryRepository categoyRepository, IExpenseRepository expenseRepository) {     this.categoyRepository = categoyRepository;     this.expenseRepository = expenseRepository; } //Get Expense transactions based on dates 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 startdate's month, if endate is not passed     if (StartDate.HasValue && !EndDate.HasValue)     {         EndDate = (new DateTime(StartDate.Value.Year, StartDate.Value.Month, 1)).AddMonths(1).AddDays(-1);     }       var expenses = expenseRepository.GetExpenseTransactions(StartDate.Value, EndDate.Value);     if (Request.IsAjaxRequest())     {           return PartialView("ExpenseList", expenses);     }     ViewData.Add("StartDate", StartDate.Value.ToShortDateString());     ViewData.Add("EndDate", EndDate.Value.ToShortDateString());             return View(expenses);            }   // GET: /Expense/Edit public ActionResult Edit(string id) {       var expenseModel = new ExpenseViewModel();     var expense = expenseRepository.Load(id);     ModelCopier.CopyModel(expense, expenseModel);     var categories = categoyRepository.GetCategories();     expenseModel.Category = categories.ToSelectListItems(expense.Category.Id.ToString());                    return View("Save", expenseModel);          }   // // GET: /Expense/Create   public ActionResult Create() {     var expenseModel = new ExpenseViewModel();               var categories = categoyRepository.GetCategories();     expenseModel.Category = categories.ToSelectListItems("-1");     expenseModel.Date = DateTime.Today;     return View("Save", expenseModel); }   // // POST: /Expense/Save // Insert/Update Expense Tansaction [HttpPost] public ActionResult Save(ExpenseViewModel expenseViewModel) {     try     {         if (!ModelState.IsValid)         {               var categories = categoyRepository.GetCategories();                 expenseViewModel.Category = categories.ToSelectListItems(expenseViewModel.CategoryId);                               return View("Save", expenseViewModel);         }           var expense=new Expense();         ModelCopier.CopyModel(expenseViewModel, expense);          expenseRepository.Save(expense, expenseViewModel.CategoryId);                       return RedirectToAction("Index");     }     catch     {         return View();     } } //Delete a Expense Transaction public ActionResult Delete(string id) {     expenseRepository.Delete(id);     return RedirectToAction("Index");     }     }     Download the Source - You can download the source code from http://ravenmvc.codeplex.com

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  • ASP.NET in Moscow!

    - by Latest Microsoft Blogs
    I’m traveling to Russia and speaking in Moscow next week at the DevConf. This will be the first time that I have visited Russia, and I know that there is a strong ASP.NET community in Russia, so I am very excited about the trip. I’m speaking at the DevConf Read More......(read more)

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  • Asp.net session on browser close

    - by budugu
    Note: Cross posted from Vijay Kodali's Blog. Permalink How to capture logoff time when user closes browser? Or How to end user session when browser closed? These are some of the frequently asked questions in asp.net forums. In this post I'll show you how to do this when you're building an ASP.NET web application. Before we start, one fact: There is no full-proof technique to catch the browser close event for 100% of time. The trouble lies in the stateless nature of HTTP. The Web server is out of the picture as soon as it finishes sending the page content to the client. After that, all you can rely on is a client side script. Unfortunately, there is no reliable client side event for browser close. Solution: The first thing you need to do is create the web service. I've added web service and named it AsynchronousSave.asmx.    Make this web service accessible from Script, by setting class qualified with the ScriptServiceAttribute attribute...  Add a method (SaveLogOffTime) marked with [WebMethod] attribute. This method simply accepts UserId as a string variable and writes that value and logoff time to text file. But you can pass as many variables as required. You can then use this information for many purposes. To end user session, you can just call Session.Abandon() in the above web method. To enable web service to be called from page’s client side code, add script manager to page. Here i am adding to SessionTest.aspx page When the user closes the browser, onbeforeunload event fires on the client side. Our final step is adding a java script function to that event, which makes web service calls. The code is simple but effective My Code HTML:( SessionTest.aspx ) C#:( SessionTest.aspx.cs ) That’s’ it. Run the application and after browser close, open the text file to see the log off time. The above code works well in IE 7/8. If you have any questions, leave a comment.

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  • A simple DotNetNuke article module with C# and VB.NET Source

    - by Chris Hammond
    For the DotNetNuke Connections conference last month I provided an advanced DotNetNuke module development course as a pre-conference training session. That training covered details on how to implement some of the newer features in the DotNetNuke platform within custom modules, mainly ContentItem integration and Taxonomy features. For the course I created a very basic Article module for DotNetNuke, ultimately naming it DNNSimpleArticle. For the course I created both a C# and a VB.NET version of the...(read more)

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  • Membership in ASP.Net applications - part 3

    - by nikolaosk
    This is the third post in a series of posts regarding ASP.Net built in membership functionality,providers,controls. You can read the first one post one here . You can read the second post here . In this post I would like to investigate how to use the Membership class methods to achieve the same functionality we have with the login web server controls.The login web server controls live inside the .aspx pages and access the underlying abstract membership classes to perform the desired functionality...(read more)

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  • Setting up Visual Studio 2010 to step into Microsoft .NET Source Code

    - by rajbk
    Using the Microsoft Symbol Server to obtain symbol debugging information is now much easier in VS 2010. Microsoft gives you access to their internet symbol server that contains symbol files for most of the .NET framework including the recently announced availability of MVC 2 Symbols.  SETUP In VS 2010 RTM, go to Tools –> Options –> Debugging –> General. Check “Enable .NET Framework source stepping” We get the following dialog box   This automatically disables “Enable My Code”   Go to Debugging –> Symbols and Check “Microsoft Symbol Servers”. You can selectively exclude modules if you want to.   You will get a warning dialog like so: Hitting OK will start the download process   The setup is complete. You are now ready to start debugging! DEBUGGING Add a break point to your application and run the application in debug mode (F5 shortcut for me). Go to your call stack when you hit the break point. Right click on a frame that is grayed out. Select “Load Symbols from” “Microsoft Symbol Servers”. VS will begin a one time download of that assembly. This assembly will be cached locally so you don’t have to wait for the download the next time you debug the app.   We get a one time license agreement dialog box You might see an error like the one below regarding different encoding (hopefully will be fixed).    Assemblies for which the symbols have been loaded are no longer grayed out. Double clicking on any entry in the call stack should now directly take you to the source code for that assembly. AFAIK, not all symbols are available on the MS symbol server. In cases like that you will see a tab like the one below and be given the option to “Show Disassembly”. Enjoy! Newsreel Announcer: Humiliated, Muntz vows a return to Paradise Falls and promises to capture the beast alive! Charles Muntz: [speaking to a large audience outside in the newsreel] I promise to capture the beast alive, and I will not come back until I do!

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  • Functions inside page using Razor View Engine – ASP.NET MVC

    - by hajan
    As we already know, Razor is probably the best view engine for ASP.NET MVC so far. It keeps your code fluid and very expressive. Besides the other functionalities Razor has, it also supports writing local functions. If you want to write a function, you can’t just open new @{ } razor block and write it there… it won’t work. Instead, you should specify @functions { } so that inside the brackets you will write your own C#/VB.NET functions/methods. Lets see an example: 1. I have the following loop that prints data using Razor <ul> @{     int N = 10;     for (int i = 1; i<=N; i++)     {         <li>Number @i</li>     }     } </ul> This code will print the numbers from 1 to 10: Number 1 Number 2 Number 3 Number 4 Number 5 Number 6 Number 7 Number 8 Number 9 Number 10 So, now lets write a function that will check if current number is even, if yes… add Even before Number word. Function in Razor @functions{     public bool isEven(int number)     {         return number % 2 == 0 ? true : false;     } } The modified code which creates unordered list is: <ul> @{     int N = 10;     for (int i = 1; i<=N; i++)     {         if (isEven(@i)) {             <li>Even number @i</li>         }         else {             <li>Number @i</li>         }                 }             } </ul> As you can see, in the modified code we use the isEven(@i) function to check if the current number is even or not… The result is: Number 1 Even number 2 Number 3 Even number 4 Number 5 Even number 6 Number 7 Even number 8 Number 9 Even number 10 So, the main point of this blog was to show how you can define your own functions inside page using Razor View Engine. Of course you can define multiple functions inside the same @functions { } defined razor statement. The complete code: @{     Layout = null; } <!DOCTYPE html> <html> <head>     <title>ASP.NET MVC - Razor View Engine :: Functions</title> </head> <body>     <div>         <ul>         @{             int N = 10;             for (int i = 1; i<=N; i++)             {                 if (isEven(@i)) {                     <li>Even number @i</li>                 }                 else {                     <li>Number @i</li>                 }                         }                     }         </ul>         @functions{             public bool isEven(int number)             {                 return number % 2 == 0 ? true : false;             }         }     </div> </body> </html> Hope you like it. Regards, Hajan

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  • ASP.NET developers build rich management system using the VWG extension

    - by Visual WebGui
    When The Center for Organ Recovery & Education (CORE) decided they needed a web application to allow easy access to the expenses management system they initially went to ASP.NET web forms combined with CSS. The outcome, however, was not satisfying enough as it appeared bland and lacked in richness. So in order to enrich the UI and give the web application some glitz, Visual WebGui was selected. Visual WebGui provided the needed richness and the familiar Windows look and feel also made the transition...(read more)

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  • ASP.NET Meta Keywords and Description

    - by Ben Griswold
    Some of the ASP.NET 4 improvements around SEO are neat.  The ASP.NET 4 Page.MetaKeywords and Page.MetaDescription properties, for example, are a welcomed change.  There’s nothing earth-shattering going on here – you can now set these meta tags via your Master page’s code behind rather than relying on updates to your markup alone.  It isn’t difficult to manage meta keywords and descriptions without these ASP.NET 4 properties but I still appreciate the attention SEO is getting.  It’s nice to get gentle reminder via new coding features that some of the more subtle aspects of one’s application deserve thought and attention too.  For the record, this is how I currently manage my meta: <meta name="keywords"     content="<%= Html.Encode(ConfigurationManager.AppSettings["Meta.Keywords"]) %>" /> <meta name="description"     content="<%= Html.Encode(ConfigurationManager.AppSettings["Meta.Description"]) %>" /> All Master pages assume the same keywords and description values as defined by the application settings.  Nothing fancy. Nothing dynamic. But it’s manageable.  It works, but I’m looking forward to the new way in ASP.NET 4.

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  • jQuery + Perl CGI to vb.net transition

    - by user1257458
    I've been developing oracle database-heavy "web applications" forever by building my html by hand, adding some jquery to handle ajax requests (html inserts for forms processing etc), and always did my server side stuff in perl cgi. I really love how easy it is to read some form input, execute some select statements through dbi (SO EASY), and generate HTML to be inserted by the jquery request. That's a web application to me. However, my new boss builds everything in visual studio 2010, vb.net, usually webforms. So, for work reasons, I now need to start developing in vb.net so it can be collectively maintained, and I'm just seeking advice on where to start learning/how to approach this. I know I could at least learn ASP.net and VB.net, and create a webform, have it read parameters, return HTML, etc. which would allow me to use my previously written HTML and client-side scripts (jQuery). Although- since we're moving heavily to mobile applications I really need to reduce client-side processing load. Is there any advantage to my boss' method? Thanks a ton.

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  • A basic T4 template for generating Model Metadata in ASP.NET MVC2

    - by rajbk
    I have been learning about T4 templates recently by looking at the awesome ADO.NET POCO entity generator. By using the POCO entity generator template as a base, I created a T4 template which generates metadata classes for a given Entity Data Model. This speeds coding by reducing the amount of typing required when creating view specific model and its metadata. To use this template, Download the template provided at the bottom. Set two values in the template file. The first one should point to the EDM you wish to generate metadata for. The second is used to suffix the namespace and classes that get generated. string inputFile = @"Northwind.edmx"; string suffix = "AutoMetadata"; Add the template to your MVC 2 Visual Studio 2010 project. Once you add it, a number of classes will get added to your project based on the number of entities you have.    One of these classes is shown below. Note that the DisplayName, Required and StringLength attributes have been added by the t4 template. //------------------------------------------------------------------------------ // <auto-generated> // This code was generated from a template. // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------   using System; using System.ComponentModel; using System.ComponentModel.DataAnnotations;   namespace NorthwindSales.ModelsAutoMetadata { public partial class CustomerAutoMetadata { [DisplayName("Customer ID")] [Required] [StringLength(5)] public string CustomerID { get; set; } [DisplayName("Company Name")] [Required] [StringLength(40)] public string CompanyName { get; set; } [DisplayName("Contact Name")] [StringLength(30)] public string ContactName { get; set; } [DisplayName("Contact Title")] [StringLength(30)] public string ContactTitle { get; set; } [DisplayName("Address")] [StringLength(60)] public string Address { get; set; } [DisplayName("City")] [StringLength(15)] public string City { get; set; } [DisplayName("Region")] [StringLength(15)] public string Region { get; set; } [DisplayName("Postal Code")] [StringLength(10)] public string PostalCode { get; set; } [DisplayName("Country")] [StringLength(15)] public string Country { get; set; } [DisplayName("Phone")] [StringLength(24)] public string Phone { get; set; } [DisplayName("Fax")] [StringLength(24)] public string Fax { get; set; } } } The gen’d class can be used from your project by creating a partial class with the entity name and setting the MetadataType attribute.namespace MyProject.Models{ [MetadataType(typeof(CustomerAutoMetadata))] public partial class Customer { }} You can also copy the code in the metadata class generated and create your own ViewModel class. Note that the template is super basic  and does not take into account complex properties. I have tested it with the Northwind database. This is a work in progress. Feel free to modify the template to suite your requirements. Standard disclaimer follows: Use At Your Own Risk, Works on my machine running VS 2010 RTM/ASP.NET MVC 2 AutoMetaData.zip Mr. Incredible: Of course I have a secret identity. I don't know a single superhero who doesn't. Who wants the pressure of being super all the time?

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  • ASP.NET MVC for the php/asp noob

    - by dotjosh
    I was talking to a friend today, who's foremost a php developer, about his thoughts on Umbraco and he said "Well they're apparently working feverishly on the new version of Umbraco, which will be MVC... which i still don't know what that means, but I know you like it." I ended up giving him a ground up explanation of ASP.NET MVC, so I'm posting this so he can link this to his friends and for anyone else who finds it useful.  The whole goal was to be as simple as possible, not being focused on proper syntax. Model-View-Controller (or MVC) is just a pattern that is used for handling UI interaction with your backend.  In a typical web app, you can imagine the *M*odel as your database model, the *V*iew as your HTML page, and the *C*ontroller as the class inbetween.  MVC handles your web request different than your typical php/asp app.In your php/asp app, your url maps directly to a php/asp file that contains html, mixed with database access code and redirects.In an MVC app, your url route is mapped to a method on a class (the controller).  The body of this method can do some database access and THEN decide which *V*iew (html/aspx page) should be displayed;  putting the controller in charge and not the view... a clear seperation of concerns that provides better reusibility and generally promotes cleaner code. Mysite.com, a quick example:Let's say you hit the following url in your application: http://www.mysite.com/Product/ShowItem?Id=4 To avoid tedious configuration, MVC uses a lot of conventions by default. For instance, the above url in your app would automatically make MVC search for a .net class with the name "Product" and a method named "ShowItem" based on the pattern of the url.  So if you name things properly, your method would automatically be called when you entered the above url.  Additionally, it would automatically map/hydrate the "int id" parameter that was in your querystring, matched by name.Product.cspublic class Product : Controller{    public ViewResult ShowItem(int id)    {        return View();    }} From this point you can write the code in the body of this method to do some database access and then pass a "bag" (also known as the ViewData) of data to your chosen *V*iew (html page) to use for display.  The view(html) ONLY needs to be worried about displaying the flattened data that it's been given in the best way it can;  this allows the view to be reused throughout your application as *just* a view, and not be coupled to HOW the data for that view get's loaded.. Product.cspublic class Product : Controller{    public ViewResult ShowItem(int id)    {        var database = new Database();        var item = database.GetItem(id);        ViewData["TheItem"] = item;        return View();    }} Again by convention, since the class' method name is "ShowItem", it'll search for a view named "ShowItem.aspx" by default, and pass the ViewData bag to it to use. ShowItem.aspx<html>     <body>      <%        var item =(Item)ViewData["TheItem"]       %>       <h1><%= item.FullProductName %></h1>     </body></html> BUT WAIT! WHY DOES MICROSOFT HAVE TO DO THINGS SO DIFFERENTLY!?They aren't... here are some other frameworks you may have heard of that use the same pattern in a their own way: Ruby On Rails Grails Spring MVC Struts Django    

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  • Watching Green Day and discovering Sitecore, priceless.

    - by jonel
    I’m feeling inspired and I’d like to share a technique we’ve implemented in Sitecore to address a URL mapping from our legacy site that we wanted to carry over to the new beautiful Littelfuse.com. The challenge is to carry over all of our series URLs that have been published in our datasheets, we currently have a lot of series and having to create a manual mapping for those could be really tedious. It has the format of http://www.littelfuse.com/series/series-name.html, for instance, http://www.littelfuse.com/series/flnr.html. It would have been easier if we have our information architecture defined like this but that would have been too easy. I took a solution that is 2-fold. First, I need to create a URL rewrite rule using the IIS URL Rewrite Module 2.0. Secondly, we need to implement a handler that will take care of the actual lookup of the actual series. It will be amazing after we’ve gone over the details. Let’s start with the URL rewrite. Create a new blank rule, you can name it with anything you wish. The key part here to talk about is the Pattern and the Action groups. The Pattern is nothing but regex. Basically, I’m telling it to match the regex I have defined. In the Action group, I am telling it what to do, in this case, rewrite to the redirect.aspx webform. In this implementation, I will be using Rewrite instead of redirect so the URL sticks in the browser. If you opt to use Redirect, then the URL bar will display the new URL our webform will redirect to. Let me explain one small thing, the (\w+) in my Pattern group’s regex, will actually translate to {R:1} in my Action’s group. This is where the magic begins. Now let’s see what our Redirect.aspx contains. Remember our {R:1} above which becomes the query string variable s? This are basic .Net code. The only thing that you will probably ask is the LFSearch class. It’s our own implementation of addressing finding items by using a field search, we supply the fieldname, the value of the field, the template name of the item we are after, and the value of true or false if we want to do an exact search, or not. If eureka, then redirect to that item’s Path (Url). If not, tell the user tough luck, here’s the 404 page as a consolation. Amazing, ain’t it?

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  • Include weather information in ASP.Net site from weather.com services

    - by sreejukg
    In this article, I am going to demonstrate how you can use the XMLOAP services (referred as XOAP from here onwards) provided by weather.com to display the weather information in your website. The XOAP services are available to be used for free of charge, provided you are comply with requirements from weather.com. I am writing this article from a technical point of view. If you are planning to use weather.com XOAP services in your application, please refer to the terms and conditions from weather.com website. In order to start using the XOAP services, you need to sign up the XOAP datafeed. The signing process is simple, you simply browse the url http://www.weather.com/services/xmloap.html. The URL looks similar to the following. Click on the sign up button, you will reach the registration page. Here you need to specify the site name you need to use this feed for. The form looks similar to the following. Once you fill all the mandatory information, click on save and continue button. That’s it. The registration is over. You will receive an email that contains your partner id, license key and SDK. The SDK available in a zipped format, contains the terms of use and documentation about the services available. Other than this the SDK includes the logos and icons required to display the weather information. As per the SDK, currently there are 2 types of information available through XOAP. These services are Current Conditions for over 30,000 U.S. and over 7,900 international Location IDs Updated at least Hourly Five-Day Forecast (today + 4 additional forecast days in consecutive order beginning with tomorrow) for over 30,000 U.S. and over 7,900 international Location IDs Updated at least Three Times Daily The SDK provides detailed information about the fields included in response of each service. Additionally there is a refresh rate that you need to comply with. As per the SDK, the refresh rate means the following “Refresh Rate” shall mean the maximum frequency with which you may call the XML Feed for a given LocID requesting a data set for that LocID. During the time period in between refresh periods the data must be cached by you either in the memory on your servers or in Your Desktop Application. About the Services Weather.com will provide you with access to the XML Feed over the Internet through the hostname xoap.weather.com. The weather data from the XML feed must be requested for a specific location. So you need a location ID (LOC ID). The XML feed work with 2 types of location IDs. First one is with City Identifiers and second one is using 5 Digit US postal codes. If you do not know your location ID, don’t worry, there is a location id search service available for you to retrieve the location id from city name. Since I am a resident in the Kingdom of Bahrain, I am going to retrieve the weather information for Manama(the capital of Bahrain) . In order to get the location ID for Manama, type the following URL in your address bar. http://xoap.weather.com/search/search?where=manama I got the following XML output. <?xml version="1.0" encoding="UTF-8"?> <!-- This document is intended only for use by authorized licensees of The –> <!-- Weather Channel. Unauthorized use is prohibited. Copyright 1995-2011, –> <!-- The Weather Channel Interactive, Inc. All Rights Reserved. –> <search ver="3.0">       <loc id="BAXX0001" type="1">Al Manama, Bahrain</loc> </search> You can try this with any city name, if the city is available, it will return the location id, and otherwise, it will return nothing. In order to get the weather information, from XOAP,  you need to pass certain parameters to the XOAP service. A brief about the parameters are as follows. Please refer SDK for more details. Parameter name Possible Value cc Optional, if you include this, the current condition will be returned. Value can be anything, as it will be ignored e.g. cc=* dayf If you want the forecast for 5 days, specify dayf=5 This is optional iink Value should be XOAP par Your partner id. You can find this in your registration email from weather.com prod Value should be XOAP key The license key assigned to you. This will be available in the registration email unit s or m (standard or matric or you can think of Celsius/Fahrenheit) this is optional field, if not specified the unit will be standard(s) The URL host for the XOAP service is http://xoap.weather.com. So for my purpose, I need the following request to be made to access the XOAP services. http://xoap.weather.com/weather/local/BAXX0001?cc=*&link=xoap&prod=xoap&par=*********&key=************** (The ***** to be replaced with the corresponding alternatives) The response XML have a root element “weather”. Under the root element, it has the following sections <head> - the meta data information about the weather results returned. <loc> - the location data block that provides, the information about the location for which the wheather data is retrieved. <lnks> - the 4 promotional links you need to place along with the weather display. Additional to these 4 links, there should be another link with weather channel logo to the home page of weather.com. <cc> - the current condition data. This element will be there only if you specify the cc element in the request. <dayf> - the forcast data as you specified. This element will be there only if you specify the dayf in the request. In this walkthrough, I am going to capture the weather information for Manama (Location ID: BAXX0001). You need 2 applications to display weather information in your website. A Console application that retrieves data from the XMLOAP and store in the SQL Server database (or any data store as you prefer).This application will be scheduled to execute in every 25 minutes using windows task scheduler, so that we can comply with the refresh rate. A web application that display data from the SQL Server database Retrieve the Weather from XOAP I have created a console application named, Weather Service. I created a SQL server database, with the following columns. I named the table as tblweather. You are free to choose any name. Column name Description lastUpdated Datetime, this is the last time when the weather data is updated. This is the time of the service running TemparatureDateTime The date and time returned by XML feed Temparature The temperature returned by the XML feed. TemparatureUnit The unit of the temperature returned by the XML feed iconId The id of the icon to be used. Currently 48 icons from 0 to 47 are available. WeatherDescription The Weather Description Phrase returned by the feed. Link1url The url to the first promo link Link1Text The text for the first promo link Link2url The url to the second promo link Link2Text The text for the second promo link Link3url The url to the third promo link Link3Text The text for the third promo link Link4url The url to the fourth promo link Link4Text The text for the fourth promo link Every time when the service runs, the application will update the database columns from the XOAP data feed. When the application starts, It is going to get the data as XML from the url. This demonstration uses LINQ to extract the necessary data from the fetched XML. The following are the code segment for extracting data from the weather XML using LINQ. // first, create an instance of the XDocument class with the XOAP URL. replace **** with the corresponding values. XDocument weather = XDocument.Load("http://xoap.weather.com/weather/local/BAXX0001?cc=*&link=xoap&prod=xoap&par=***********&key=c*********"); // construct a query using LINQ var feedResult = from item in weather.Descendants() select new { unit = item.Element("head").Element("ut").Value, temp = item.Element("cc").Element("tmp").Value, tempDate = item.Element("cc").Element("lsup").Value, iconId = item.Element("cc").Element("icon").Value, description = item.Element("cc").Element("t").Value, links = from link in item.Elements("lnks").Elements("link") select new { url = link.Element("l").Value, text = link.Element("t").Value } }; // Load the root node to a variable, you may use foreach construct instead. var item1 = feedResult.First(); *If you want to learn more about LINQ and XML, read this nice blog from Scott GU. http://weblogs.asp.net/scottgu/archive/2007/08/07/using-linq-to-xml-and-how-to-build-a-custom-rss-feed-reader-with-it.aspx Now you have all the required values in item1. For e.g. if you want to get the temperature, use item1.temp; Now I just need to execute an SQL query against the database. See the connection part. using (SqlConnection conn = new SqlConnection(@"Data Source=sreeju\sqlexpress;Initial Catalog=Sample;Integrated Security=True")) { string strSql = @"update tblweather set lastupdated=getdate(), temparatureDateTime = @temparatureDateTime, temparature=@temparature, temparatureUnit=@temparatureUnit, iconId = @iconId, description=@description, link1url=@link1url, link1text=@link1text, link2url=@link2url, link2text=@link2text,link3url=@link3url, link3text=@link3text,link4url=@link4url, link4text=@link4text"; SqlCommand comm = new SqlCommand(strSql, conn); comm.Parameters.AddWithValue("temparatureDateTime", item1.tempDate); comm.Parameters.AddWithValue("temparature", item1.temp); comm.Parameters.AddWithValue("temparatureUnit", item1.unit); comm.Parameters.AddWithValue("description", item1.description); comm.Parameters.AddWithValue("iconId", item1.iconId); var lstLinks = item1.links; comm.Parameters.AddWithValue("link1url", lstLinks.ElementAt(0).url); comm.Parameters.AddWithValue("link1text", lstLinks.ElementAt(0).text); comm.Parameters.AddWithValue("link2url", lstLinks.ElementAt(1).url); comm.Parameters.AddWithValue("link2text", lstLinks.ElementAt(1).text); comm.Parameters.AddWithValue("link3url", lstLinks.ElementAt(2).url); comm.Parameters.AddWithValue("link3text", lstLinks.ElementAt(2).text); comm.Parameters.AddWithValue("link4url", lstLinks.ElementAt(3).url); comm.Parameters.AddWithValue("link4text", lstLinks.ElementAt(3).text); conn.Open(); comm.ExecuteNonQuery(); conn.Close(); Console.WriteLine("database updated"); } Now click ctrl + f5 to run the service. I got the following output Check your database and make sure, the data is updated with the latest information from the service. (Make sure you inserted one row in the database by entering some values before executing the service. Otherwise you need to modify your application code to count the rows and conditionally perform insert/update query) Display the Weather information in ASP.Net page Now you got all the data in the database. You just need to create a web application and display the data from the database. I created a new ASP.Net web application with a default.aspx page. In order to comply with the terms of weather.com, You need to use Weather.com logo along with the weather display. You can find the necessary logos to use under the folder “logos” in the SDK. Additionally copy any of the icon set from the folder “icons” to your web application. I used the 93x93 icon set. You are free to use any other sizes available. The design view of the page in VS2010 looks similar to the following. The page contains a heading, an image control (for displaying the weather icon), 2 label controls (for displaying temperature and weather description), 4 hyperlinks (for displaying the 4 promo links returned by the XOAP service) and weather.com logo with hyperlink to the weather.com home page. I am going to write code that will update the values of these controls from the values stored in the database by the service application as mentioned in the previous step. Go to the code behind file for the webpage, enter the following code under Page_Load event handler. using (SqlConnection conn = new SqlConnection(@"Data Source=sreeju\sqlexpress;Initial Catalog=Sample;Integrated Security=True")) { SqlCommand comm = new SqlCommand("select top 1 * from tblweather", conn); conn.Open(); SqlDataReader reader = comm.ExecuteReader(); if (reader.Read()) { lblTemparature.Text = reader["temparature"].ToString() + "&deg;" + reader["temparatureUnit"].ToString(); lblWeatherDescription.Text = reader["description"].ToString(); imgWeather.ImageUrl = "icons/" + reader["iconId"].ToString() + ".png"; lnk1.Text = reader["link1text"].ToString(); lnk1.NavigateUrl = reader["link1url"].ToString(); lnk2.Text = reader["link2text"].ToString(); lnk2.NavigateUrl = reader["link2url"].ToString(); lnk3.Text = reader["link3text"].ToString(); lnk3.NavigateUrl = reader["link3url"].ToString(); lnk4.Text = reader["link4text"].ToString(); lnk4.NavigateUrl = reader["link4url"].ToString(); } conn.Close(); } Press ctrl + f5 to run the page. You will see the following output. That’s it. You need to configure the console application to run every 25 minutes so that the database is updated. Also you can fetch the forecast information and store those in the database, and then retrieve it later in your web page. Since the data resides in your database, you have the full control over your display. You need to make sure your website comply with weather.com license requirements. If you want to get the source code of this walkthrough through the application, post your email address below. Hope you enjoy the reading.

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  • NoSQL with MongoDB, NoRM and ASP.NET MVC - Part 2

    - by shiju
     In my last post, I have given an introduction to MongoDB and NoRM using an ASP.NET MVC demo app. I have updated the demo ASP.NET MVC app and a created a new drop at codeplex. You can download the demo at http://mongomvc.codeplex.com/In my last post, we have discussed to doing basic CRUD operations against a simple domain entity. In this post, let’s discuss on domain entity with deep object graph.The below is our domain entities  public class Category {       [MongoIdentifier]     public ObjectId Id { 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 List<Expense> Expenses { get; set; }       public Category()     {         Expenses = new List<Expense>();     } }    public class Expense {     [MongoIdentifier]     public ObjectId Id { get; set; }     public Category Category { get; set; }     public string  Transaction { get; set; }     public DateTime Date { get; set; }     public double Amount { 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.The MongoSession class  internal class MongoSession : IDisposable {     private readonly MongoQueryProvider provider;       public MongoSession()     {         this.provider = new MongoQueryProvider("Expense");     }       public IQueryable<Category> Categories     {         get { return new MongoQuery<Category>(this.provider); }     }     public IQueryable<Expense> Expenses     {         get { return new MongoQuery<Expense>(this.provider); }     }     public MongoQueryProvider Provider     {         get { return this.provider; }     }       public void Add<T>(T item) where T : class, new()     {         this.provider.DB.GetCollection<T>().Insert(item);     }       public void Dispose()     {         this.provider.Server.Dispose();     }     public void Delete<T>(T item) where T : class, new()     {         this.provider.DB.GetCollection<T>().Delete(item);     }       public void Drop<T>()     {         this.provider.DB.DropCollection(typeof(T).Name);     }       public void Save<T>(T item) where T : class,new()     {         this.provider.DB.GetCollection<T>().Save(item);                }     }     ASP.NET MVC view model  for Expense transaction  public class ExpenseViewModel {     public ObjectId Id { get; set; }       public ObjectId 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; } }  Let's create action method for Insert and Update a expense transaction   [HttpPost] public ActionResult Save(ExpenseViewModel expenseViewModel) {     try     {         if (!ModelState.IsValid)         {             using (var session = new MongoSession())             {                 var categories = session.Categories.AsEnumerable<Category>();                 expenseViewModel.Category = categories.ToSelectListItems(expenseViewModel.CategoryId);                }             return View("Save", expenseViewModel);         }           var expense=new Expense();         ModelCopier.CopyModel(expenseViewModel, expense);           using (var session = new MongoSession())         {             ObjectId Id = expenseViewModel.CategoryId;             var category = session.Categories                 .Where(c => c.Id ==Id  )                 .FirstOrDefault();             expense.Category = category;             session.Save(expense);         }         return RedirectToAction("Index");     }     catch     {         return View();     } } Query with Expenses  using (var session = new MongoSession()) {     var expenses = session.Expenses.         Where(exp => exp.Date >= StartDate && exp.Date <= EndDate)         .AsEnumerable<Expense>(); }  We are doing a LINQ query expression with a Date filter. We can easily work with MongoDB using NoRM driver and can managing object graph of domain entities are pretty cool. Download the Source - You can download the source code form http://mongomvc.codeplex.com

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  • Asynchronous Streaming in ASP.NET WebApi

    - by andresv
     Hi everyone, if you use the cool MVC4 WebApi you might encounter yourself in a common situation where you need to return a rather large amount of data (most probably from a database) and you want to accomplish two things: Use streaming so the client fetch the data as needed, and that directly correlates to more fetching in the server side (from our database, for example) without consuming large amounts of memory. Leverage the new MVC4 WebApi and .NET 4.5 async/await asynchronous execution model to free ASP.NET Threadpool threads (if possible).  So, #1 and #2 are not directly related to each other and we could implement our code fulfilling one or the other, or both. The main point about #1 is that we want our method to immediately return to the caller a stream, and that client side stream be represented by a server side stream that gets written (and its related database fetch) only when needed. In this case we would need some form of "state machine" that keeps running in the server and "knows" what is the next thing to fetch into the output stream when the client ask for more content. This technique is generally called a "continuation" and is nothing new in .NET, in fact using an IEnumerable<> interface and the "yield return" keyword does exactly that, so our first impulse might be to write our WebApi method more or less like this:           public IEnumerable<Metadata> Get([FromUri] int accountId)         {             // Execute the command and get a reader             using (var reader = GetMetadataListReader(accountId))             {                 // Read rows asynchronously, put data into buffer and write asynchronously                 while (reader.Read())                 {                     yield return MapRecord(reader);                 }             }         }   While the above method works, unfortunately it doesn't accomplish our objective of returning immediately to the caller, and that's because the MVC WebApi infrastructure doesn't yet recognize our intentions and when it finds an IEnumerable return value, enumerates it before returning to the client its values. To prove my point, I can code a test method that calls this method, for example:        [TestMethod]         public void StreamedDownload()         {             var baseUrl = @"http://localhost:57771/api/metadata/1";             var client = new HttpClient();             var sw = Stopwatch.StartNew();             var stream = client.GetStreamAsync(baseUrl).Result;             sw.Stop();             Debug.WriteLine("Elapsed time Call: {0}ms", sw.ElapsedMilliseconds); } So, I would expect the line "var stream = client.GetStreamAsync(baseUrl).Result" returns immediately without server-side fetching of all data in the database reader, and this didn't happened. To make the behavior more evident, you could insert a wait time (like Thread.Sleep(1000);) inside the "while" loop, and you will see that the client call (GetStreamAsync) is not going to return control after n seconds (being n == number of reader records being fetched).Ok, we know this doesn't work, and the question would be: is there a way to do it?Fortunately, YES!  and is not very difficult although a little more convoluted than our simple IEnumerable return value. Maybe in the future this scenario will be automatically detected and supported in MVC/WebApi.The solution to our needs is to use a very handy class named PushStreamContent and then our method signature needs to change to accommodate this, returning an HttpResponseMessage instead of our previously used IEnumerable<>. The final code will be something like this: public HttpResponseMessage Get([FromUri] int accountId)         {             HttpResponseMessage response = Request.CreateResponse();             // Create push content with a delegate that will get called when it is time to write out              // the response.             response.Content = new PushStreamContent(                 async (outputStream, httpContent, transportContext) =>                 {                     try                     {                         // Execute the command and get a reader                         using (var reader = GetMetadataListReader(accountId))                         {                             // Read rows asynchronously, put data into buffer and write asynchronously                             while (await reader.ReadAsync())                             {                                 var rec = MapRecord(reader);                                 var str = await JsonConvert.SerializeObjectAsync(rec);                                 var buffer = UTF8Encoding.UTF8.GetBytes(str);                                 // Write out data to output stream                                 await outputStream.WriteAsync(buffer, 0, buffer.Length);                             }                         }                     }                     catch(HttpException ex)                     {                         if (ex.ErrorCode == -2147023667) // The remote host closed the connection.                          {                             return;                         }                     }                     finally                     {                         // Close output stream as we are done                         outputStream.Close();                     }                 });             return response;         } As an extra bonus, all involved classes used already support async/await asynchronous execution model, so taking advantage of that was very easy. Please note that the PushStreamContent class receives in its constructor a lambda (specifically an Action) and we decorated our anonymous method with the async keyword (not a very well known technique but quite handy) so we can await over the I/O intensive calls we execute like reading from the database reader, serializing our entity and finally writing to the output stream.  Well, if we execute the test again we will immediately notice that the a line returns immediately and then the rest of the server code is executed only when the client reads through the obtained stream, therefore we get low memory usage and far greater scalability for our beloved application serving big chunks of data.Enjoy!Andrés.        

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