C# Tutorial

Linq - Select only latest revision

2011-11-02T08:19:00.000-07:00

I'm doing a different approach to what I normally do on my new home page. I'm storing all my data with revisions. Update a photo or an article and it is stored in my database with a new revision.A simple entity might look something like this:

Person
--
int id
int revision
string name

Now, my challenge was to retrieve persons from my database, but only the latest revision. So I wrote myself some Linq that looks a bit like this:

public IEnumerable<Person> GetPersons()
{
    return  from person in Person.All()
            group person by person.Id
            into personGroup
            from entity in personGroup
            where entity.Revision == personGroup.Max(x => x.Revision)
            select entity;
}

And it returns a list of unique persons, but only the latest revision of each.

Unit testing with mock objects

2011-10-27T03:54:00.000-07:00

This article is meant as a short tutorial on how to use an isolation framework. I prefer Moq for my .NET projects, but I'm sure there are other good alternatives out there. Moq can be pulled from NuGet. Simply add it to your test project and you're good to go.

When do we use mocking? The answer is, we use mocking when we need to isolate a unit for testing. Let's say I have a method that pulls a resource from the internet, looks at it and returns a list of strings. What we want to test is how different inputs gives different results, not the actual operation of opening the web page and streaming data.

I have some code ready and I will demonstrate how to write some tests for it. In the code below, I download and go through an xml document and look for nodes containing names:

public List<string> FetchData(string url)
{
    // Get XmlDocument using WebClient
    var document = new XmlDocument();
    document.Load(new WebClient().OpenRead(url));
           
    // Go through the document and aggregate a list of strings
    var list = new List<string>();
    foreach (var node in document.GetElementsByTagName("name"))
    {
        list.Add(((XmlNode) node).InnerText);
    }

    return list;
}

Separate concerns

Now, the first thing I have to do is to take out the code that talks to the internet. This way, I can inject different result data and see how it affects the output. I simply set up a wrapper for the WebClient, so that the rest of the code can be isolated for testing. Here's my wrapper class:

public interface IWebClientWrapper
{
    XmlDocument FetchXml(string url);
}

Here's an implementation of my interface:

public class WebClientWrapper : IWebClientWrapper
{
    public XmlDocument FetchXml(string url)
    {
        // Do stuff and return XmlDocument
    }
}

Now, I have a separate unit that speeks with the internet and a separate unit that interprets the results. I've set up the wrapper class with an interface so that it can be mocked for testing. Either that or its methods would have to be marked as virtual.

Prep the code

Next, in my web-fetch-thing-class, I set up a new property, WebClientWrapper. The property has the type IWebClientProxy. If it is not set, it will simply create a new instance. This pattern allows me to inject a custom instance of IWebClientProxy for testing.

private IWebClientWrapper _webClientWrapper;
public IWebClientWrapper WebClientWrapper
{
    get
    {
        if (_webClientWrapper == null)
            _webClientWrapper = new WebClientWrapper();
        return _webClientWrapper;
    }
    set { _webClientWrapper = value; }
}

My FetchData method now looks like this:

public List<string> FetchData(string url)
{
    // Get XmlDocument from the WebClient wrapper class
    var document = WebClientWrapper.FetchXml(url);

    // Go through the document and aggregate a list of strings
    var list = new List<string>();
    foreach (var node in document.GetElementsByTagName("name"))
    {
        list.Add(((XmlNode) node).InnerText);
    }

    return list;
}

Testing the code

Let's take a look at the actual tests. I wanted to test how different results affects how my method aggregates a list of names. Let's start with some code:

var webClientWrapper = new Mock<IWebClientWrapper>();
webClientWrapper
   .Setup(x => x.FetchXml(It.IsAny<string>()))
   .Returns((XmlDocument)null);

In the snippet above, we've created a new instance of a Mock class of the type IWebClientWrapper. We've set up the method FetchXml(...) to take any input, so long as it is of the type String and we've stated that it should return null. Note how we have to do casting when we want to return null. This is because the Return(...) method has overloads, and we have to explicitly tell which one we are using.

Next, have a look at how we inject the mock object. Remember how I made the WebClient wrapper into a property?

var webFetcher = new WebFetcher 
                 { 
                    WebClientWrapper = webClientWrapper.Object 
                 };

Now, I can excute my method, and see how it behaves. I actually want it to throw an exception if the WebClient returns null. Have a look at the full test:

[TestMethod]
[ExpectedException(typeof(Exception), AllowDerivedTypes = true)]
public void WebFetcher_TestWithNullDocument_ShouldThrowException()
{
    // Setup
    var webClientWrapper = new Mock<IWebClientWrapper>();
    webClientWrapper.Setup(x => x.FetchXml(It.IsAny<string>())).Returns((XmlDocument)null);

    var webFetcher = new WebFetcher 
                     { 
                        WebClientWrapper = webClientWrapper.Object 
                     };

    // Execute
    webFetcher.FetchData("http://www.somewhere.com/validUrl/");
}

I also want to see how the results are when we provide a valid xml document. Have a look at the following test:

[TestMethod]
public void WebFetcher_TestWithValidExampleData_ShouldReturnXmlDocument()
{
    // Setup
    var document = new XmlDocument();
    document.LoadXml("<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?><names><name>Brian</name><name>John</name></names>");

    var webClientWrapper = new Mock<IWebClientWrapper>();
    webClientWrapper.Setup(x => x.FetchXml(It.IsAny<string>())).Returns(document);

    var webFetcher = new WebFetcher 
                     { 
                        WebClientWrapper = webClientWrapper.Object 
                     };

    // Execute
    var list = webFetcher.FetchData("http://www.somewhere.com/validUrl/");

    // Assert
    Assert.IsNotNull(list);
    Assert.IsInstanceOfType(list, typeof (List));
    Assert.IsTrue(list.Count != 0);
    Assert.IsTrue(list.Contains("Brian"));
    Assert.IsTrue(list.Contains("John"));
}

I will have to make some changes in my original code. At least now, It's more testable and I can see how different input data affects the output.

The code is posted on Bitbucket if you want to have a look:
https://bitbucket.org/andersnygaard/webfetcherthingy/src

DOS on Dope - ASP.NET MVC the old school way

2011-07-22T05:52:00.000-07:00

Would you like to combine old school DOS skills with modern day web frameworks? Then DOS on dope might be something for you. Everything is written in DOS .bat scripts. Yes, everything. Views and controllers are all familiar .bat scripts.

I've set up a small home page with a single Index view under a Home controller as you would expect from a simple MVC application. Here's the source:

@echo off
call ..\..\Views\Shared\_header Web Page
call ..\..\h\h1 Welcome to my web page

echo [strong] This web page is under construction [/strong]

echo.
echo [blockquote]
echo [ul]
pushd %cd%
cd ..
FOR /F "delims=~" %%A IN (' DIR /B/a:d') DO (
 echo [li][a href='%%A/']%%A[/a][/li]
)
echo [/ul]
echo [/blockquote]

echo [table]
echo [tr]
echo [td]
echo [img src = "Content/anders.jpeg" width = "150"][/img]
echo [/td]
echo [td width = "400" valign = "top"]
echo Hi, I am Anders, and this is my web page. Feel free to browse around and explore my life and works.
echo [br]
echo [br]
echo Be shure you head over to
echo [a href = "http://dod.codeplex.com/"]http://dod.codeplex.com/[/a]
echo where you can learn how to make your own web page
echo [/td]
echo [/tr]
echo [/table]
echo [blink][a href = "Content/index.bat.txt"]Forget Razor, check out this awesome MVC syntax[/a][blink]

::echo [blockquote][pre]"C:\Temp\Blog\Controllers\Home\Index.bat"[/pre][/blockquote]

Nice, or what?

Links:
http://external2.webtop.no/dodblog/
http://dod.codeplex.com/

Code kata challenge #2

2011-07-15T05:40:00.000-07:00

I've been playing around with linq-like functionality as a code kata the last few days. I've simplified the my Where method and made a simple skip and take function. I can now do this without the actual linq namespace:

var results = list
    .Skip(2)
    .Take(200)
    .Where(x => x % 2 == 0);

My Skip method:

public static IEnumerable<T> Skip<T>(
    this IEnumerable<T> list, int count)
{
    var enumerator = list.GetEnumerator();
    for (var i = 0; i < count; i++)
        enumerator.MoveNext();

    while (enumerator.MoveNext())
        yield return enumerator.Current;
}

My Take method:

public static IEnumerable<T> Take<T>(
        this IEnumerable<T> list, int count)
{
    var enumerator = list.GetEnumerator();
    enumerator.MoveNext();
    for (var i = 0; i < count; i++)
    {
        yield return enumerator.Current;
        enumerator.MoveNext();
    }
}

My Where method:

public static IEnumerable<T> Where<T>(
    this IEnumerable<T> list, Predicate<T> expression)
{
    foreach(var item in list)
        if(expression(item))
            yield return item;
}

It's darned fast too. Delayed excecution rocks.

Code kata challenge

2011-07-12T23:22:00.000-07:00

Code kata is a term coined by Dave Thomas, author of several programming books. He suggest you do small exercises regularly in order to keep yourself fit as a programmer.

No doubt, this can be usefull, but doing a small bank account example ten times over doesn't make you fully capable of writing financial applications. In the real world you are likely to meet real world challenges.

Now, what I like are challenges that make me better at core features or work methods. I like challenges like "here's a set of tests, write the method that makes them all pass". If you're good at that, you we'll be better at working with unit tests (TDD in fact).

After watching Justin Etheredge on Linq over at Tekpub, I've got an idea for a code kata. Recreate the Linq functions like Justin does in episode 1. Once you've got the hang of one, move to the next. That should keep you busy for the next month or so and you will be the master of new language features like extension methods, collection initializers, delegates, anonymous delegates, and lambas.

Here's how you might extend IEnumerable in order to implement a WHERE method:

using System;
using System.Collections.Generic;

namespace Linq.Kata
{
    public static IEnumerable<T> Where<T>(
        this IEnumerable<T> list, Predicate<T> expression)
    {
        foreach(var item in list)
            if(expression(item))
                yield return item;
    }    
}

This method extends IEnumerable and takes a function delegate as parameter. We traverse the list and execute the delegate function on each item in the list. The method would be called like this:

var integerlist = new int[] {1, 2, 3, 4, 5, 6};
var integerResukts = integerlist.KataWhere(x => x % 2 == 0);

var stringList = new string[] {"anders", "christian"};
var stringResults = stringList.KataWhere(x => x == "anders");

Some links:

Kata Catalogue
http://codingdojo.org/cgi-bin/wiki.pl?KataCatalogue

Mastering Linq @ Tekpub
http://tekpub.com/view/linq/1

Scalable source control

2011-06-29T00:05:00.000-07:00

I recently started a small pet project. Using ASP.NET MVC3 with EF Code First, I think I've managed to keep it all small and tidy. But, if you add a set of tests, a bit of advanced jQuery in the front end and a custom authentication service on top of that, it's time to add a source control system. Here's what I've done as my project has grown:

- Day one, I placed my project in a Dropbox folder. That way, I could reach my project files from all my computers (and even my iPhone).

- A few weeks later, when I first had to make some serious changes and needed a fallback, I created a Mercurial repository in my Dropbox folder and commited all my code. I've got a blogpost on that here: http://csharptutorial.blogspot.com/2011/06/using-dropbox-with-mercurial.html. Mercurial is a great source control system, because it doesn't require a server installation and your repository is copied to all locations where it's checked out.

- Now, I'm looking at moving my project over to BitBucket (http://bitbucket.org/) which is a free hosting service (up to five users I think). It allows you to share code and has an issue tracker system.

A good alternative to Mercurial is Git, using github.com in stead of bitbucket.org. Both have a learning curve, but they both represent modern version control tools and is well worth having a look at.

Using DropBox with Mercurial

2011-06-09T11:09:00.000-07:00

Here's a short guide to setup a Mercurial repository in a DropBox folder. You'll need a DropBox account set up and Turtoise Hg installed.

First, create a DropBox folder for your Hg repository. I've got a project called Places, so I created a directory ./Projects/HGRepositories/Places

Inside your project directory, right click anywhere, then go TortoiseHg->Create Repository Here

Follow the instructions. The destination directory should be the same as the one with your project.

After you've finished initializing your repository, you should have the .hg folder and the .hgignore file added to your directory.

Set up the ignore list.

Copy the entire project directory over to your DropBox directory

Next, from your project directory, open the Hg Repository Explorer.

From the Repository Explorer, Commit your project.

Now, push your changesets to the DropBox repository.

And there you go. Your repository now has backup and is available from any computer that has access to your DropBox folders. In order to check out at another computer. Create an empty folder. Inside it, right click and choose TortoiseHg->Clone and clone the repository from the shared DropBox folder.

Using Razor views with Webforms master page

2011-01-26T01:21:00.000-08:00

While the new Razor view enginge for ASP.NET MVC3 looks fantastic, I haven't been able to dive into it quite yet. I soon discovered that you cannot mix and match Razor views with your old Webforms master page. You could have two master pages, but ideally you don't want to write the same code and markup twice.

Scott Hanselman presents a solution. "Can I mix Razor Views and WebForms Views in a single ASP.NET MVC application?", he asks. The answer is, "No, Yes, and Maybe, But It's Not Supported."

Anyways, the solutions is found on his blog.

In order to get the page title to work properly, I've done the following:

In the Controller:

ViewBag._Title = "Admin";

In the RazorView.aspx:

<%
    if (ViewBag._Title != null)
        Page.Title = ViewBag._Title;
%>

jQuery.appendTemplate v 1.2.1

2011-01-08T13:50:00.000-08:00

A minor release with updated demo example and minified javascript included is now released. Read more on the jQuery plugin website or check out the appendTemplate tag on this blog.

New design

2010-12-21T02:24:00.001-08:00

I've made a major upgrade on the blog today. Since I first started this blog, the template tools at blogger.com has become way more advanced and at the same time, way more easy. So enjoy and let me know if the new design is a total miss.

HTML 5 Gelolocation

2010-12-16T11:19:00.000-08:00

I wanted to make a simple application with the new HTML 5 geolocation API. Since it's not yet supported by all browsers, it seemed like a good idea to take a look at the Modernizr script as well.

Modernizr creates a javascript object containing tests for the new HTML5 tags. This information can be used to provide the new and exciting features to those who has a modern browser and an alternative to those who has an old one. So called graceful degredation.

Geolocation is supported by the following browsers:

Firefox 3.5+
Opera 10.6+
Chrome 5+
Safari 5+
Internet Explorer 9+

The code

The example below first checks if geolocation is available, then tries to use it. The user will be prompted for permission to use the current location. If the user declines we have to have a failover for that as well.


// Check for geolocation support
if (Modernizr.geolocation) {
  navigator.geolocation.getCurrentPosition(function(position) {
    // Success
    $("#geolocation").text("Your position is: "
      + position.coords.latitude + ", " 
      + position.coords.longitude);

  }, function() {
    // Failed
    $("#geolocation").text("You declined to share location");
  });
}
// Geolocation is not available
else {
  $("#geolocation").text("Geolocation is not available for your.");
}

View the complete demo here.

10 tricks that will make your jQuery enabled site go faster

2010-12-14T04:33:00.000-08:00

During the last few weeks, I've had the chance to go more in depth with jQyery and general site performance. I've found some techniques that makes my site go much faster. I don't know if they're all best practice, but this article is meant to at least give you some good ideas.

$(document).ready(e) vs $(window).load(e)

The .ready(e) function fires when a dom element is ready. That's why we use it on the document element. When the document element is ready, the page is also, sort of. Actually the page is not ready until the window is fully loaded with images and other resources, but we're allowed to start manipulating the DOM at an earlier stage. I recomend doing your DOM manipulation, resizing, setup menus etc first and then start your ajax calls once the page is fully rendered.

So put your design oriented code in the $(document).ready(e) function and your data oriented code in the $(window).load(e). That way, the page components come to place at an earlier stage and that creates the illusion of speed.

Load JSON from string

In order to avoid the extra cost of doing a page request you can actually include JSON in the page as a string. For instance, I use a jQuery framework to build my menu, but the page lags a bit while waiting for the external scripts that loads the menu elements. I found that the user experience is much faster if I include the menu items as a javascript string at the bottom of the page. The main page will take some milliseconds extra loading, but the menu lagging will dissapear. I then set up the menu in the $(document).ready(e) function and set up the menu before the page data loads.


var menuJSON = '[{....}]'
$(document).ready(function () {
 var menuObject = $.parseJSON(menuJSON);
}

Store repositories in memory

If you load JSON or XML from another script with ajax, keep the returned object in a variable in the window scope. That way, you can do live search and sort operations quickly without loading external resources again. I know some like to do sort in the database, but modern browsers can do it quite quick. It depends on the size of the dataset of course.


var userRepository;
$(window).load(function(){
 userRepository = $.ajax(....);
 doSomething(userRepository);
});

Setup events last

You can save a bit of loading time by adding events last. First layout, then data, and then events. Events aren't visible and we want the visible parts of your web site to load first, right? What you could do is to disable buttons until they're loaded with events. This example uses jQueryUI.


$(document).ready(function(){
 $(":button").button("disable");
});

and then, once an event has been added do all your button code:


(window).load(function(){
 $("#button").click(....);
 $("#button").button("enable");
 (...)
});

Unbind events

If you never unbind your events, you could potentially consume quite a lot of unnecessary memory. Even worse you could stack up double events and your click function or keypress trapper could be executed twice. In order to make sure that there's only one click funtion on a DOM element do the following:


$("#button").unbind("click");
$("#button").click(....);

.empty() vs html("")

This one is related to the one above. If you write .html("") when you want to empty a div or a list, then there's no guarantee that the events assigned to the child DOM elements are unbound. The jQuery manual states:

"To avoid memory leaks, jQuery removes other constructs such as data and event handlers from the child elements before removing the elements themselves."

So, always use .empty() in stead of .html("")

Load your javascripts at bottom of the page

The new best practice is to load CSS in the head and javascripts at the end of the body. It actually works. If you do, then the page will have read the rest of the page before starting to manipulate it. Hence it appears much faster.

Since javascripts are getting quite heavy in size, it is actually better to let the page load divs and images before large chunks of javascripts. jQuery is just under 80 kb, jQueryUI another 200 kb and I bet you have a few other scripts as well. It all adds up and makes your site slower.

Also, rumors has it that some web search engines only reads a certain amout of text before leaving for another page, and therefore you will be able to present more of the important stuff first.

Don't use a content delivery system

Unless you run a site with tens of thousands of visitors daily or your bandwith costs are very hight, I see no reason to use a CDN. I think what they are trying to achieve is a caching effect. If your visitors allready have the recent jQuery framework cached from Google, they won't have to when they go to your site. But in my experience, CDNs are always a performance drag. They all tend to go slower than my on web hosting and that looses the whole meaning of using these services.

Download the custom version of jQueryUI

The full version of jQueryUi is just under 200kb in size. If you only use button functionallity, you only touch the tip of the iceberg. The custom version of jQueryUI which only holds the core funtionallity and the button package only takes about 13,9 kb. Do the maths, the custom version takes the jQueryUI from being the heaviest file you load on your page to being on of the smallest.

This also explains a problem with using a CDN, since they only have the large version on their site (probably).

RTFM

I mean it, are you familiar with the special selectors in jQuery? How about the .live(...) funtion? It's all in the jQuery documentation. Use it.

The ad blocker mystery

2010-12-09T03:37:00.000-08:00

I've just come to realize how important it is for me to run an ad blocker at work. First of all I don't like opening a web site and then start looking for the real content amongst the blinking ad banners. I just don't. And it seems to me that norwegian web sites are the worst. Try visiting www.dinside.no without safety goggles and you'll se what I mean. That site is plain awfull sometimes. www.digi.no has som much ads that they don't even have room for a main article image.

Anyways
We've had some problems with ad blockers blocking items on our web site, so today I've spent some time figuring out how they work. Turns out, there's nothing magical about them. They simply block content based on script naming. Consider these two scripts:

createNew.asp?id=1671

vs

createNew.asp?id=1671&adName=myName

I load them both into an iframe after the page first has been rendered, but one of them is stopped. The last one actually gets blocked because of the querystring variable adName.

Solution
Choose your names wisely. Our system actually is for making ads, so names containing ad*** seemed quite natural at one time. The guys over at Sitepoint has some articles on this topic and this one is worth a read:

http://blogs.sitepoint.com/2009/05/27/file-naming-important/

jQuery.appendTemplate v 1.2

2010-11-11T06:06:00.000-08:00

Just released a new version of the jQuery.appendTemplate plugin. Fixed a cache issue and gained about 33% speed increase. Also, the plugins now loads in sync, which means the DOM update and callback function will work better together.

Why the web will ultimately win

2010-11-10T01:06:00.000-08:00

Ten years ago, I had a Palm Pilot. The Palm OS was a winner. It had a simple programming language (C-based, I think), a form application framework and a database. That's it. None or very few apps came with any graphics. Still, you could download tens of thousands of applications back then. Fart logs, excercise diarys, vinyl databases and so on.

Ten years later there's three platforms covering that same market, iOS, Android and Windows Mobile. Nokia is eager to get back into the lead, and you still have Java for all of those old fashion mobile phones.

So, if you write a sucessful fart log application on one of these platforms, odds are that you would like to expand onto another platform and you would have to fork your code in order to do so.

My prediction is that the web will be the leading platform in a few years. Safari is big on iOS, Opera is taking the lead on other smart phones. Firefox is still in beta (alpha?) with their Fennec browser. Internet Explorer, I haven't tried on the new WinMo 7, but chances are that there will be a browser war on mobile units. And that's going to benefit all of us.

New features will be hardware accellerated graphics and javascripts, localization, use of onboard camera and so on.

I've even tried writing a small app using HTML+javascript myself. This is a port of one of my favourite iPhone apps, FloodIt. It may not be perfected quite yet, but it works. And for me, it's a great demo of a cross browser app that even runs smoothly on Windows and Mac. Try it yourself and think about it, it might just be the future.

http://www.ettsted.no/games/floodfill

EDIT: The game should work on IE 8, Firefox 3, Chrome 7, iPhone, Android and possibly WinMo 6.5 with Opera mini

jQuery.appendTemplate v 1.1

2010-10-15T03:36:00.000-07:00

I've uploaded a new release to my jQuery appendTemplate plugin over at jQuery Plugins. The new version includes:

- caching of templates
- callback function

Link:
http://plugins.jquery.com/project/appendTemplate

jQuery.appendTemplate(url, args[])

2010-10-12T06:45:00.000-07:00

Appends a template from file onto an element.

url: template url
args[]: dynamic list of arguments that goes into the template

Example code:


$(document).ready(function(){
$.getJSON(
  "data/data.json",
  function(data){

  $.each(data, function(i, item){
    $("#myList").appendTemplate(
      "templates/row.template",
      item.url,
      item.text);
  });

});         
});

So what does it do?

The appendTemplate function loads a template from file and fills it with the arguments you pass. Sort of like a string.format(args[]) function.

Author

Written by Anders Nygaard. Fan or hate mail: anders.nygaard at googles mail service

Download

On my wish list: Static extension methods

2010-10-05T01:25:00.001-07:00

Ideally, I want to remove as much lambda expressions as possible out of my repository classes. Using Subsonic, I want to implement my own fluent methods which do not require any lambda in the implemented repository class at all.

Now, please correct me if I'm wrong, but while you can make a generic extension class you can't really make static extension methods in c#? Code would be something like this:


public static class GeneralExtension{
   public static T ById(this T entity, int id) where T: IActiveRecord
   {
      return T.SingleOrDefaul(x=>x.Id == id);
   }
}

And implementation would be something like this:


public class TaskRepository : IScrumblrRepository
{
   public Task Get(int id)
   {
      return Task.ById(id);
   }
}

If I find a smooth way of doing this without the use of static extension methods, I'll let you know.

Oh my, another IE bug

2010-07-15T01:27:00.000-07:00

You can spend all the time you want trying to make beautiful design, clever solutions with jQuery and CSS. It all works perfect in Firefox, Chrome and Opera. It even validates perfectly as XHTML strict with the W3C validators. And then, there's the time consuming monster called Internet Explorer.

Today, I spend half an hour on a silly little bug I've never seen before. It turns out, Internet Explorer doesn't like empty select tags, which by the way is perfectly legal xhtml.

If you don't add any options, IE will never interpret the closing select tag, and your content will never show. White screen of death.

Firefox:

Internet Explorer:

Applies to:
IE6, IE7, IE8

Testing Subsonic based projects

2010-05-12T06:07:00.000-07:00

Testing Subsonic based projects is a breeze. No mock frameworks needed. All you have to do is add an app.config file and some mock objects righ into Subsonic. Have a look at the following:

In the App.config file of my test project:


<connectionstrings>
   <add name="VisenoConnection" connectionstring="Test">
   </add>
</connectionstrings>

My Setup method:

[SetUp]
public void StartTest()
{
    List companies = new List();
    for (int i = 0; i < 100; i++)
    {
        VisenoCompany company = new VisenoCompany();
        company.Id = i;
        company.Name = "webtop";
        company.Address = "address";
        companies.Add(company);
    }

    companies[1].CompanyKey = "123";

    VisenoCompany.Setup(companies);
}

My test method:

[Test]
public void TestGetCompany()
{
CompanyRepository companyRepository = new CompanyRepository();
VisenoCompany company = companyRepository.Get(1);
Assert.That(company.Id == 1);
Assert.That(company.CompanyKey == "123");
Assert.That(company.Name == "webtop");
(...)

Subsonic now uses memory in stead of database. In this case the repositories and generated classes are even in a different project.

Changing the Visual Studio start page feed to show news from Dotnetkicks

2009-09-18T01:19:00.000-07:00

Open Visual Studio and navigate to Tools-Options-Environment-Startup

Change the start page news channel variable to

http://feeds.feedburner.com/dotnetkicks

There you go, Dotnetkicks in the Visual Studio start page

Save as Indesign .inx (CS2)

2009-02-10T00:07:00.000-08:00

Ok, a bit off topic, but here's some thoughts on file formats and monopoly organisations.

This week, we got Adobe CS4 Design Premium at work. We need this because designers send us Indesign documents made with Creative Suite 3 or 4 and we still use CS2. I took it for granted that Adobe incorporates backwards compatibility, but no. This is cut/pasted from Adobes web pages:

"To open the InDesign CS4 document in InDesign CS2, open the exported INX file in InDesign CS3, export to INX again, and then open the exported file in InDesign CS2. Make sure that all versions have been updated."

The past year, Microsoft have had to defend their file format policy, BUT, Microsoft Office IS compatible with older versions. You can even save to html and old formats back to Office 95. How Adobe gets away with their policy on this subject is not quite as apparent to me...

Luftguitar CMS released

2008-04-01T01:05:00.001-07:00

The project

The Luftguitar CMS project is a great platform for small or medium sized web portals. It is made with simplicity in mind and at the same time it offers a great deal of flexibility when it comes to customization.

The Goal

The philosophy is that
- most users don't like to manage user roles and frontpage layout, they want a simple system that just works.
- most designers don't like javascript, they want simple html and css.
- most developers don't like hacking old code, they want to make new cool features fast.

http://sourceforge.net/projects/luftguitarcms

Including Unit Testing

2007-10-07T03:36:00.001-07:00

It struck me as a great idea to include NUnit test in the next release of my SQLite query browser. If the program crashes or misbehaves, users can run the tests, find out why and either report to me or fix it themselves. Being one person and writing this program as a hobby, I don't have the capacity of testing that many different platforms and setups myself.

Let me show you what I have in mind:

The user clicks help-> run tests from the toolstrip

NUnit starts

The NUnit licence says: "Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely (...)"

I've included the entire NUnit bin directory and my test library dll in the project root and these few lines of code on the toolstrip onclick event:

private void runTestsToolStripMenuItem_Click(object sender, EventArgs e)
{
Process nunit = new Process();

nunit.StartInfo.FileName = Application.StartupPath + "\\nunit\\nunit.exe";
nunit.StartInfo.Arguments = "SQLiteQHTest.dll /run";

nunit.Start();
}

Optimizing code using a stop watch

2007-03-05T03:55:00.001-08:00

NET 2 has a stop watch, which sometimes comes in handy when it comes to identifying slow code and optimizing performance. The StopWatch object can be found under the System.Diagnostics namespace and contains methods Start() and Stop().

In order to identify the time spent on excecuting a method, you could try something like this:

System.Diagnostics.Stopwatch watch = new System.Diagnostics.Stopwatch();
watch.Start();

DoMyStuff();

watch.Stop();
WriteToScreen("Time spent: " + watch.Elapsed.ToString());

For instance, you can use this method to measure if you gain from creating indexes in your database layer or the time spent on sorting lists etc.

SQLite GUI for Windows

2006-12-03T05:17:00.000-08:00

I've made a small windows application for doing queries with SQLite 3.x databases which uses the ADO.NET Data Provider for SQLite.

SQLite is small file-based database format and resembles Microsoft's Access format. It's portable and unlike Access it has "normal" data types and secutity properties. It supports databases up to 2TB in size and its free to use.

SQLite can be found at:
http://www.sqlite.org/

The ADO.NET dataprovider can be downloaded from:
http://sourceforge.net/projects/adodotnetsqlite

My little SQLite query application can be downloaded from:
http://sourceforge.net/projects/sqlitequery

Anthem.NET

2006-11-30T02:34:00.000-08:00

I've been working with the Anthem package for a while and it still blows me away. Anthem.NET is a web project that does exactly what Microsoft should have done when they first started out with ASP.NET.

What is Anthem?

Anthem is an open source project from web developer Jason Diamonds written in C#, Javascript and ASP.NET. The project contains numerous webcomponents pretty much like the ASP.NET framework except these controls are AJAX enabled.

How does it work?

Anthem relies heavily on callbacks in stead of postbacks. It uses Javascript to send the page wievstate to the .aspx page and does this AJAX-style in stead of refreshing the whole page on every component change. After callback, the Anthem components refreshes some of its inner html and values.

The Anthem way of exchanging data to and from the server makes little or no inpact on the code behind or the ASP.NET script. As a programmer, you still write your codebehind and your html and use components as you would the .NET way.

Is this something for me?

Anthem is still in an alpha stage. As with other open source projects and in the spirit of web 2.0, it could be stuck in beta mode for years to come. Documentation is also lacking or non-existant, so you better have some time available.

Also, Anthem doesn't come right out of the box, as you have to create a solution, import the right project files, compile and import the .dll into the Visual Studio toolbox. Not that hard, but yes - it's one of those small time consuming tasks.

You can find Anthem.NET on SourceForge and this adress:

http://sourceforge.net/projects/anthem-dot-net

Reading xml fast

2006-10-11T01:56:00.000-07:00

Using the System.Diagnostics.StopWatch object, I've made an interesting experiment on how to read a 1mb xml file fast. For this experiment, I've made a small console application and for each of the different code examples, I then traverse the xml tree and write the values to the console. Last, I've tried a smaller file 5kb in order to see if the result is the same when working with smaller files.

The xml is quite simple and looks something like this:

entry

name

adress

(...)

StreamReader

For a reference, I've started off with a simple stream read:


StreamReader reader = File.OpenText("c:\\testfile2.xml");
string input = null;
while ((input = reader.ReadLine()) != null)
{
  Console.WriteLine(input);
}

And the result:
watch.Elapsed = {00:00:02.3910558}

The result is pretty much as expected, about two seconds to read all of the lines an put them on the screen.

XMLReader

Next up is the xml reader. It traverses the xml straight forward and reads all of the nodes.


FileStream stream = new FileStream("c:\\testfile2.xml", FileMode.Open);
XmlReader reader = new XmlTextReader(stream);
while(reader.Read())
{
  Console.WriteLine(reader.Value);
}

And the result:
watch.Elapsed = {00:00:12.7904473}

12 seconds is about as expected. There's some overhead with finding the xml nodes, but it all seem pretty much like expected. If we would try this experiment over the internet or a slower file network, I believe that the xml reader overhead would not be that visible.

XPath

Next, we try the xPath aproach:


FileStream stream = new FileStream("c:\\testfile2.xml", FileMode.Open);
XPathDocument document = new XPathDocument(stream);
XPathNavigator navigator = document.CreateNavigator();
XPathNodeIterator node = navigator.Select("xml/entry");
for(...){...}

And the result:
watch.Elapsed = {00:03:29.5681325}

I knew it would take some time, but this is not acceptable. XPath is still a kind of favourite as it makes it possible to navigate the xml tree in a absolutely beautiful way.

DataSet

Next is the dataset approach.


DataSet ds = new DataSet();
ds.ReadXml("C:\\testfile2.xml");
foreach (DataTable tbl in ds.Tables)
{
  foreach (DataRow dr in tbl.Rows)
  {
     for (...){...}
  }
}

And the result:
watch.Elapsed = {00:00:03.6352829}

I'm a bit surprised. The dataset seems like the fastest way of traversing an xml file. Note that dataset navigation can be cumbersome when containing a lot of tables, like the one.

A smaller xmlfile

I've also tried the same aproaches to a 5kb xml file, here's the results and now it turns out XPath is the fastest method:

FileStream:
watch.Elapsed = {00:00:00.0144736}

XMLReader:
watch.Elapsed = {00:00:00.0302896}

Xpath:
watch.Elapsed = {00:00:00.0151563}

Dataset:
watch.Elapsed = {00:00:00.0225523}

Supersimple GDI+ graphics acceleration

2006-08-23T00:54:00.000-07:00

I wanted to learn Direct3D.. Actually, all I wanted was to experiment with a 2D scroller game, but I figured out from browsing the net that it would require me to have a look at the 3D library.
I dind't have the time and forgot about it.

A few months later I am making a HTPC type of software. Sure I use DirectX for audio, but it would be overkill to use Direct3D to write a few text strings and images onto the screen.

In stead, I use GDI+, the good old Graphics object. It's flicker free and quite fast. As a demo, I did a remake of the classic Space Invaders game and it turned out to run quite smooth.

Have a look at the following example, it should get you started:

public class MainForm : Form
{
private Graphics g;
private Bitmap backbuffer;

public MainForm()
{
backbuffer = new Bitmap(this.Width, this.Height);
g = Graphics.FromImage(backbuffer);

// All painting will occur in the Paint event handler
this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint |
ControlStyles.OptimizedDoubleBuffer, true);
}

private void MainForm_Paint(object sender, PaintEventArgs e)
{
g.Clear(Color.Black);

// Draw stuff here

// Flip the backbuffer onto the screen
e.Graphics.DrawImage(backbuffer, new Point(0, 0));

// Draw graphics again
this.Invalidate(false)
}
}

Question mark: The ternary operator ?

2006-05-19T07:43:00.000-07:00

You want to write short blocks of code and you want to write readable code. Usually, there's a fine line, as you don't want your code looking like the works of a l33t h4X0r script kid or a python minimalist.

A fine way of both shortening and simplifying is if you use the question mark. It's called a ternary operator. With this, you can do conditional assignments on one line.

Consider the following example (taken from Bresenhams line algorithm) :

int ystep;
if(y0<y1)
{
ystep = 1;
}
else
{
ystep = -1;
}

The code above could be shortened to one line:

int ystep = y0 < y1 ? 1 : -1;

Custom Exceptions

2006-05-16T06:57:00.000-07:00

Custom Exceptions

Exceptions are your friends. So is garbage collection :D Well, you shouldn't really ignore Exceptions, in stead, if you just learn yourself a little about them, your code could be easier to understand and easier to debug.

Custom Exceptions allows you to make more narrow, specific Exceptions with customized messages. This often makes it easier to pinpoint where your application fails from a higher persepective. By using InnerExceptions, you can also track back the original error message.

In the following example, I throw my own custom Exception object using the caught DataAdapterException as an InnerException.


try
{
 myConnection.Open();
 myDataAdapter.Fill(ds_records);
}

catch(Exception err)
{
 throw new MyCustomException(
              "Database error: Unable to fill dataset", err);
}

finally
{
 connection.Close();
}

Now lets make the MyCustomException. First off, lets make a base class _ErrorException which inherits from the Exception class and write the following methods. We'll make the class Serializable, so that .NET is able to serialize the Exception. If the exception is ever used in a remoting context, exceptions on the server are serialized and remoted back to the client proxy. These base constructors are called each time we create a new Exception.


[Serializable]
public class _ErrorException : Exception
{
public string ErrorMessage
{
get
{
    return base.Message.ToString();
}
}

public _ErrorException(string errorMessage)
                   : base(errorMessage) {}

public _ErrorException(string errorMessage, Exception innerEx)
                   : base(errorMessage, innerEx) {}
}

Now lets create a class MyCustomException which inherits from _ErrorException:


public class MyCustomException : _ErrorException
{
public InternalErrorException(string errorMessage)
                             : base(errorMessage) {}   

public InternalErrorException(string errorMessage, Exception innerEx)
                             : base(errorMessage, innerEx) {}
}

That's about it. Now, from the business layer of my application, I can track back to the original DataAdapterException and its original error message, but also find out other places in the code affected by the error.

Test-Driven Development (TDD)

2006-05-16T03:43:00.000-07:00

TheCodeProject has a great article on Test-Driven Development in .NET. The article explains the basics of TDD, the most common attributes, class setup and the NUnit GUI.

TheCodeProject:Test-Driven Developmen in .NET

Managed Direct X tutorials

2006-05-16T02:30:00.000-07:00

The massive amount of articles, downloads, webcasts and product sites on the MSDN network sometimes makes it a daunting task to find usefull information about a specific topic.

Looking for resources on the latest managed Direct X, I didn't manage to find anything really usefull off the Direct X MSDN home page, but half an hour later, Google had directed me to these great tutorials:

Microsoft: Code4fun

Microsoft: Video Game Development (webcasts)

Other resources:

Direct3 D Tutorial Index: Craig Andera's DirectX Wiki

Welcome to C# Tutorial

2006-05-16T02:16:00.000-07:00

Welcome to C# Tutorial. This is the workblog for Anders Nygaard, and hopefully a usefull resource blog for both you, the reader and myself. I'll start off with a low level of ambition, this is not going to be your complete resource for C#, but rather a collection of usefull tips and tricks that I stumble upon.

Nuff said, back to work :D