I like the subversion and it does the job for me, but after watching tekpub’s videos, I instantly realized the power of mercurial and why I must have it.  So I went ahead and converted my source control for dartfiles to Hg (hg is the chemical symbol for mercury in the periodic table). I was actually surprised by how easy the move went.

Here is what I did:

1. Downloaded and installed TortoiseHg
2. Exported my subversion project to a new folder 

   

3. Created a Mercurial repository at the new folder where I exported the code in step 2

   
   

4. Edited the ignore file (.hgignore) in notepad and added the following (which I found somewhere on stackoverflow)

# Ignore file for Visual Studio 2008

# use glob syntax
syntax: glob

# Ignore Visual Studio 2008 files
*.obj
*.exe
*.pdb
*.user
*.aps
*.pch
*.vspscc
*_i.c
*_p.c
*.ncb
*.suo
*.tlb
*.tlh
*.bak
*.cache
*.ilk
*.log
*.lib
*.sbr
*.scc
[Bb]in
[Db]ebug*/
obj/
[Rr]elease*/
_ReSharper*/
[Tt]est[Rr]esult*
[Bb]uild[Ll]og.*
*.[Pp]ublish.xml

5. Committed the repository

   

   

That’s all I had to do to setup mercurial. 

You are probably wondering – where is the source control server and where are you committing too.  This is the part that is different than what I have been used to with subversion.  Obviously if you are using git or similar distributed SCM then you are familiar with this concept.  Mercurial stores all your source code changes and tracking locally right in your folder inside a .hg subfolder (similar to .svn folders but not exactly).  When you commit you are just committing to your local repository.  This is pretty cool because it lets you commit locally, roll back to a different time, branch and do all kind of cool things without having to deal with a server. 

Imagine you are working on feature 1 then you get an email for an urgent bug (lets’ call it bug 2).  You can’t really work on it because feature 1 is not complete and the code won’t compile and things could get messy.  You want to fix the bug but you don’t want to lose all the work you put into feature 1 and you are note ready to deploy.  With mercurial, it’s pretty easy to handle this situation.  Simply go back to a point in your history before you started working on feature 1, create a new branch for bug 2, fix it then commit and push it, you can then deploy this version and then come back and merge the bug 2 branch with your feature 1 branch and continue working on feature 1. 

I probably didn’t do a good job explaining this scenario but hopefully you will at least get an idea of what I am talking about.  If not then head over to http://mercurial.selenic.com/ and take a look at their great documentation.

Remote Repository

In most cases, you will want to setup a remote repository so you can “push” code to it.  “Pushing” is another concept that was new to me.  Basically, you commit locally and you push remotely (or centrally).  This gives you the flexibility to commit all day long every time you make a change and only when the code is ready and stable you “push” it to the remote repository where other developers can get to it.  I setup my remote repository at bitbucket – http://bitbucket.org/ – they have a free account and some very reasonable pricing.  If you are working on open source/public code, you can always use Google code or codeplex; they both support mercurial.

Here are the steps

1. Created an account at bitbucket.
2. Setup TortoiseHg to talk with the remote repository (right-click > TortoiseHg > Repository Settings)

   

3. Pushed my code to the remote server

TeamCity Integration

I use TeamCity as my build server (blog post).  Once everything was working nicely, I had to get TeamCity to work with the new SCM.  This was pretty easy as well.  I basically removed my old SVN root from my TeamCity project and added a new root to point to mercurial

To make this work, you have to install mercurial on the server.  Get it from http://mercurial.selenic.com/downloads/

Initially, I had a problem with the HG command path and it was giving me some weird error like failed to create process or something like that (I can’t remember).  It turned out the problem was that TeamCity couldn’t deal with spaces in the path.  The install location was “c:\Program Files (x86)\hg” so I just moved it to c:\hg and everything worked.

Once everything was working well and after working for a few hours, doing a few commits and one deployment, I realized the power of mercurial.  Just take a look at my repository history and you might grasp the awesomeness that is mercurial.

Here is the dirty way:

public static string Serialize(this object obj)
{
    string XmlString = String.Empty;
    using (var memStream = new MemoryStream())
    {
        var serializer = new XmlSerializer(obj.GetType(), string.Empty);
        using (var xmlText = new XmlTextWriter(memStream, Encoding.Default))
        {
            serializer.Serialize(xmlText, obj);
        }
        XmlString = Encoding.Default.GetString(memStream.ToArray());
        memStream.Close();
    }
    return XmlString;
}

The resulting XML looks like this:

<?xml version="1.0" encoding="Windows-1252"?>
<ZipContentInfo xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <FileName>00107_tokyoatnight_1680x1050.jpg</FileName>
    <FileSize>281268</FileSize>
</ZipContentInfo>

Here is a cleaner way:

public static string Serialize(this object obj)
{
    var ser = new XmlSerializer(obj.GetType());
    using (var tw = new StringWriter())
    {
        using (var xw = XmlWriter.Create(tw, new XmlWriterSettings() { OmitXmlDeclaration = true }))
        {
            var ns = new XmlSerializerNamespaces();
            //Add an empty namespace and empty value
            ns.Add("", "");
            ser.Serialize(xw, obj, ns);
            return tw.ToString();
        }
    }
}

And the resulting XML looks like this:

<ZipContentInfo>
    <FileName>00107_tokyoatnight_1680x1050.jpg</FileName>
    <FileSize>281268</FileSize>
</ZipContentInfo>

select top 5 * from users order by newid()

Nhibernate is a different story.  I am new to NHibernate and I both love and hate it.  I hate the steep learning curve and the unobvious ways of doing things.  Anyway, here is how to select 5 random records using nhibernate.

First class a new order class to perform random ordering:

public class RandomOrder : Order
{
    public RandomOrder() : base("", true) { }
    public override SqlString ToSqlString(ICriteria criteria, ICriteriaQuery criteriaQuery)
    {
        return new SqlString("newid()");
    }
}

Then use the new class in your query:

IList<User> users = session
    .CreateCriteria(typeof(User))
    .AddOrder(new RandomOrder())
    .SetMaxResults(5)
    .List<User>();

Done…

<div id='pnlUsers'></div>
<div id='pnlMessages'></div>
<div id='pnlStatus'></div>

I can easily hide all the divs up by doing a wildcard selection on elements with an id starting with “pnl”, like this:

$("[id^=pnl]").hide();

You can even narrow it to only divs like this:

$("div[id^=pnl]").hide();

There is another example with even more explanations over here.

^(?#Protocol)(?:(?:ht|f)tp(?:s?)\:\/\/|~/|/)?(?#Username:Password)(?:\w+:\w+@)?(?#Subdomains)(?:(?:[-\w]+\.)+(?#TopLevel Domains)(?:com|org|net|gov|mil|biz|info|mobi|name|aero|jobs|museum|travel|[a-z]{2}))(?#Port)(?::[\d]{1,5})?(?#Directories)(?:(?:(?:/(?:[-\w~!$+|.,=]|%[a-f\d]{2})+)+|/)+|\?|#)?(?#Query)(?:(?:\?(?:[-\w~!$+|.,*:]|%[a-f\d{2}])+=(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)(?:&(?:[-\w~!$+|.,*:]|%[a-f\d{2}])+=(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)*)*(?#Anchor)(?:#(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)?$

There is more information on Ivan’s blog.

The code is also very simple.  I didn’t add all the extra options that the API makes available and just wrote enough for me to shorten a URL.  Here it is:

public static class BitlyApi
{
    private const string apiKey = "[add api key here]";
    private const string login = "[add login name here]";

    public static BitlyResults ShortenUrl(string longUrl)
    {
        var url =
            string.Format("http://api.bit.ly/shorten?format=xml&version=2.0.1&longUrl={0}&login={1}&apiKey={2}",
                          HttpUtility.UrlEncode(longUrl), login, apiKey);
        var resultXml = XDocument.Load(url);
        var x = (from result in resultXml.Descendants("nodeKeyVal")
                 select new BitlyResults
                            {
                                UserHash = result.Element("userHash").Value,
                                ShortUrl = result.Element("shortUrl").Value
                            }
                );
        return x.Single();
    }
}

public class BitlyResults
{
    public string UserHash { get; set; }

    public string ShortUrl { get; set; }
}

Using this code is very straight forward.

var shortUrl = BitlyApi.ShortenUrl("http://www.verylongUrl.com").ShortUrl;

bit.ly has tons of features and a great API.  You can even see stats of any bit.ly generate url using /info.  for example: http://bit.ly/info/S0vRy shows you stats for http://bit.ly/S0vRy

Another feature I really like is their bookmarklet which you can keep on your browser’s bookmark bar and click it to shrink the site you are at…  It even pops this side bar with a bunch of useful info.

The API is pretty well documented at http://code.google.com/p/bitly-api/wiki/ApiDocumentation

Don’t forget to follow me on twitter.

I created a themes folder under the content folder

Then I referenced my css file in the master page using a helper method

<%= ThemeHelper.GetCss() %>

I also use a helper method for images

<img src=’<%=ThemeHelper.GetImageUrl("reply.png")%>’ alt="reply" class="icon" />

But most of my images are set in the stylesheet, which makes it easier to manipulate different skins

The helper methods above look at the defined theme in the config file (or database or wherever you store your settings) and then return the path to the correct resource.

Take a look at these live samples:

• www.yonkly.com
• www.isweat.com
• www.hokietalk.com

They are all using the same codebase but have a different theme defined.  The trick is in making your HTML css-friendly by naming elements and assigning them classes as well as using Divs and avoiding tables.  This allows you to create a stylesheet that radically changes the look of the site.  Think of the element ids and classes as an API to your view, that the css can manipulate.

I also added a feature that lets you upload a folder theme as a zip file and have the application unzip it into the themes folder.

It would be cool if we can define a "virtual folder" in our application, so I wouldn’t have to use helper methods.  Imagine if you could just say /content/theme/logo.gif and it would just work.  The theme folder doesn’t really exist but instead it would route to the correct folder based on a setting.  I wonder if I can do that with current routing mechanism in asp.net mvc!!!  Anyone?

For example, my AccountController takes IEmailService, IFormsAuthentication and MembershipProvider (abstract class) as parameters.

During my testing, I want to mock the email, authentication and membership calls.  For example when the user calls FormsAuthentication.Login, I don’t really care if actual call succeeded but rather that my login action works appropriately in the case FormstAuthentication.Login succeeds (or fails).  I just want to mock that call.

I started off creating a few tests and slowly they have grown to several.  There was a lot of repeated code in my unit tests and to be a good citizen of the DRY universe, I needed to refactor the code.

For IoC, I initially started with StructureMap but now I am using Ninject. 

I created this module to bind my interfaces to mocked instances.  It looks like this:

internal class TestModule : StandardModule
{
    public override void Load()
    {
        Bind<IEmailService>()
            .ToConstant(MyMocks.MockEmailService.Object);

        Bind<IFormsAuthentication>()
            .ToConstant(MyMocks.MockFormsAuthentication.Object);

        Bind<MembershipProvider>()
            .ToConstant(MyMocks.MockMembershipProvider.Object);

        Bind<IContactListService>()
            .ToConstant(MyMocks.MockContactListService.Object);
    }
}

Notice that I bind the interfaces to actual instances and not classes.  These instances are declared in a global static class that will be accessed from my unit tests.  As you can tell from the name, they are all mocked objects (I am using Moq).  Here is how the MockEmailService looks (all the others are declared the same way):

internal static class MyMocks
{
    private static Mock<IEmailService> _mockEmailService;
    public static Mock<IEmailService> MockEmailService
    {
        get
        {
            _mockEmailService = _mockEmailService ?? new Mock<IEmailService>();
            return _mockEmailService;
        }
    }

So all this is good to setup Ninject and create my mocks.  Now I want to easily and generically create a controller, so I can quickly create unit tests.  In order to do that, I created a TestControllerFactory class that basically creates a controller with all the appropriate dependencies injected.

   1: internal static class TestControllerFactory

   2: {

   3:     private static IKernel _kernel;

   4:     public static IKernel Kernel

   5:     {

   6:         get

   7:         {

   8:             if (_kernel == null)

   9:             {

  10:                 var modules = new IModule[] { new TestModule() };

  11:                 _kernel = new StandardKernel(modules);

  12:             }

  13:             return _kernel;

  14:         }

  15:         private set

  16:         {

  17:             _kernel = value;

  18:         }

  19:     }

  20:  

  21:     public static T GetControllerWithFakeContext<T>(string httpMethod) 

  22:         where T : Controller

  23:     {

  24:         var con = Kernel.Get<T>();

  25:         con.SetFakeControllerContext();

  26:         if (con != null) con.Request.SetHttpMethodResult(httpMethod);

  27:         return con;

  28:     }

  29:  

  30: }

In line #10, I use the TestModule class mentioned above to setup the Ninject Kernel.  In lines #21 to #28, I create an instance of T which must be of type Controller from the Kernel which will automatically create the Controller with all the mocked objects.  In line #25 and #26, I just set a fake/mocked context and the Http Method for the request (more info here).

Now my unit tests are very clean and easy to setup.    Using MbUnit as my unit test framework, here is a unit tests that tests the reset password functionality.

   1: [Test]

   2: public void ResetPasswordQuestion_Should_Send_Email_On_Success()

   3: {

   4:     var newpassword = "newpassword";

   5:     MyMocks.MockMembershipProvider

   6:          .Expect(p => p.ResetPassword(username, answer))

   7:          .Returns(newpassword);

   8:     MyMocks.MockEmailService

   9:          .Expect(m => m.SendPasswordReset(username, newpassword));

  10:  

  11:     var ac = TestControllerFactory

  12:                 .GetControllerWithFakeContext<AccountController>("POST");

  13:  

  14:     var results = ac.ResetPasswordQuestion(username, question, answer);

  15:     //write some asserts in here to make sure things worked

  16:  

  17:     //verify all mocks

  18:     MyMocks.MockMembershipProvider.VerifyAll();

  19:     MyMocks.MockEmailService.VerifyAll();

  20: }

Line #5: I mock the ResetPassword call on the membership provider and tell it to return the new password

Line #8: I mock the SendPasswordReset method on the email service

Line #11: Get an instance of AccountController from the Ninject Kernel

I just write some code to make sure the expected results took place and that my mocks were properly exercised and that’s pretty much it.  No need to have an SMTP server working to test this, no need to have a database, no need to have an authentication method, no need to implement the interfaces or write dummy methods.

I am like a kid in a candy store with all these things: mocking, dependency injection, inversion of control, unit testing…  I am loving it.

So what do you think?  Is this a good way to go about it?  Is there a better way and what is it?

It wasn’t too hard to get up and running in asp.net mvc.  Corey’s post was a good starting point but I was too lazy to type all his code in, I wrote my own.  It was pretty easy to get Ninject to work.

I basically created a NinjecteControllerFactory class that inherits from the DefaultControllerFactory and overrode a couple of methods.  The class looks like this:

public class NinjectControllerFactory : DefaultControllerFactory
{
    private IKernel _kernel;
    public NinjectControllerFactory(params IModule[] modules)
    {
        _kernel = new StandardKernel(modules);
    }

    protected override IController GetControllerInstance(Type controllerType)
    {
        return _kernel.Get(controllerType) as IController;
    }
}

Then in my Gloval.asax.cs file, I called this code to setup Ninject.

IModule[] modules = new IModule[] { new WebModule() };
ControllerBuilder.Current.SetControllerFactory(new NinjectControllerFactory(modules));

The WebModule module has my configuration and looks like this:

public class WebModule : StandardModule
{
    public override void Load()
    {
        Bind<IAppService>().To<AspAppService>();
        Bind<IEmailService>().To<EmailService>();
        Bind<IContactService>().To<ContactService>();
        Bind<IContactRepository>().To<SqlContactRepository>();
        Bind<IFormsAuthentication>().To<FormsAuthenticationWrapper>();
        Bind<MembershipProvider>().ToConstant(Membership.Provider);
    }
}

Of course, you can create as many modules as you want to configure your application and pass them in the controller Factory.

This code was working fine for me and then Nate Kohari mentioned that there is a Ninject.Framework.Mvc extension that allows me to easily integrate Ninject into the MVC pipeline.  So, I decided to download the code, build it and use it.  I initially had some issues because it was referencing a different version of the core dll, so I had to rebuild that as well.

I changed my Global.asax.cs file to the following:

public class GlobalApplication : NinjectHttpApplication
{
    protected override void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

        routes.MapRoute(
            "Default",                                              // Route name
            "{controller}/{action}/{id}",                           // URL with parameters
            new { controller = "Home", action = "Index", id = "" }  // Parameter defaults
        );
    }

    protected override IKernel CreateKernel()
    {
        IModule[] modules = new IModule[] { new AutoControllerModule(Assembly.GetExecutingAssembly()), new WebModule() };
        return new StandardKernel(modules);
    }
}

Initially I was getting errors when navigating to an injected controller, which was fixed by add the AutoControllerModule to my modules and passing it the current assembly.

So far Ninject is looking great, the API is fluent and very discoverable and the contextual binding is very slick.  So I am going to stick with it for now and see how it goes.  The documentation seems pretty good and the Nate is very responsive in the Google Group.

Naturally, my research lead me to a post by Scott Hanselman (see it here) which lists some of the more popular IoC and dependency injection frameworks out there.

Spring.Net

I started of looking at Spring.Net and was very impressed by its features, samples/tutorials and documentation but it felt like it would be too much for this project and the learning curve seemed somewhat steep.  Its configuration syntax also looked very verbose.  But if you want to learn more there is a good article over here.

Castle Windsor

It looked easier to learn/use than spring.net but there getting started section was incomplete even though Scott says that it is well documented.  So that was a little discouraging.

Autofac

I really liked there syntax and looked really easy to use and figure out, but the documentation was very limited.  It was just a bunch of wiki pages in Google Code.  Though, they did have instructions on how to integrate it with MVC

StructureMap

Initially, I learned about structure map from a post by Phil Haack’s and I kind of liked it right away.  It was easy to pick up and figure out and Phil’s example helped to get me started quickly.  I checked there website and it has an impressive list of features and is well documented.

PostSharp

PostSharp is really cool but is not an IoC container.  It is a policy injector and a really easy way to do Aspect Oriented Programming (AOP).  Rather than trying to explain what exactly it does and screw it up, take a look at the “About PostSharp” page.  Even better check out this “getting started” walkthrough – you will be very impressed.

Must Pick One

I know there is a lot more IoC containers out there (which I glanced over), but these were sufficient for me.  Initially, I thought about using AutoFac but when I started to actually use it and ran into some issues, the documentation was not helpful at all.

I have decided to go with StructureMap as my IoC Container and dependency injector.  I might also use PostSharp to implement logging and tracing as aspects – there is no cleaner way.

Helpful Links

For a good explanation of IoC Containers and the Dependency Injection patter, read this article by Martin Fowler.

This also a good explanation that might help you understand IoC Containers.

You should definilty take a look Matthew Podwysocki’s comparison of the different IoC containers out there and their different (or rather similar) configuration and syntax.

Books you must Read

Applying Domain-Driven Design and Patterns

And Martin Fowler’s indispensable reference for software patterns Patterns of Enterprise Application Architecture

Validate my Choice

What do you think of my choice?  Does it really matter which one I go with?  Do you prefer a different IoC container and why?

Time to choose a unit testing framework… I love choices!!!

What do I want from my JavaScript Library?

I want it to be easy (I am not a JavaScript expert)
I want it to be small
I want it to be fast
I want it to be extensible
I want good documentation and/or community support
I want good/easy AJAX support
I want it to be asp.net-friendly
I also want it to be testable (I am using TDD for this project/book)
Open Source would be nice but not required

What are my options?

jQuery – http://jquery.com/
Microsoft AJAX – http://www.asp.net/ajax/
Dojo – http://dojotoolkit.org/
Prototype – http://www.prototypejs.org/
YUI – http://developer.yahoo.com/yui/

This is a shortlist but if you want a more exhaustive, read this.  I only picked these, for the simple reasons that I have heard of them and are somewhat known by the community.

3 days later

It’s been 3 days since I started this post and I have spent all that time playing around with these libraries…  I have gone back and forth in my opinion on which library to use.  I love jQuery’s selectors, ease of use and community support.  Porototype is also very popular and somewhat similar to jQuery; but I would take jQuery over Prototype for the simple reason that I like jQuery.  YUI (Yahoo! UI) library is beautiful looking and very comprehensive.

jQuery

Pros

1. Ease to learn and use
2. Beautiful syntax (the least typing)
3. Great community support and lots of fans
4. Decent Documentation
5. I already own the book
6. QUnit test framework (http://docs.jquery.com/QUnit)

Cons

1. UI isn’t that great
2. Library is not as full-featured without plugins
3. Plugins are somewhat inconsistent in quality depending on the author

Prototype

Pros

1. Good documentation
2. Good community support
3. Lots of books
   1. Practical Prototype and script-aculo.us
   2. Prototype and script.aculo.us: You Never Knew JavaScript Could Do This!
   3. and many more…
4. Great UI with the add-on script.aculo.us (http://script.aculo.us/)

Cons

1. Couldn’t find a testing framework (but I didn’t look too hard)
2. For some purely emotional reason, I prefer jQuery

YUI

Pros

1. Great UI components and styles
2. The best documented library out there, hands down.
3. Distributed hosting of JS files – the script files will be downloaded from Yahoo server, so when my site becomes a mega-hit, it will scale better.
4. Great test framework and test runner – check these demos
   
5. The most complete library
6. PDF cheat sheets for every component

Cons

1. Very verbose – not as elegant as jQuery, but that’s not too hard to fix e.g. I can assign YAHOO.util.Event to a variable $E and use $E as the shorthand.

The rest

I got tired of all the research and decided to wrap it up, so I glanced over Microsoft AJAX and Dojo and realized that there isn’t enough there to justify more research.

The winner…

When I started this post, I was pretty certain my final choice will be jQuery.  Then I started playing with Prototype and it looked really good, which kind of opened my eyes to the need to be open minded and objective.  This lead to a more objective look at YUI and the conclusion to use YUI.  I was very impressed with YUI’s look & feel, extensive documentation, testing framework and the icing on the cake was the free hosting of the JavaScript libraries.  This was a really tough decision because I still love jQuery the best.

When upgrading my production applications, I have always struggled with trying to update my production database schema to match the latest schema.  This has always been a manual, error-prone and time consuming task.  One that I always dreaded and postponed to the last minute.  It usually involved crossing my figures, praying to the SQL Gods and running a hand-made migration script against the production database.  I am not a DB guy, so you can imagine how much un-fun this was.

Long story short, you can do this with a few clicks in Visual Studio 2008. 

Start a new schema comparison

Select your source database (e.g. development database) and your target database (e.g. production database)

Click Ok.  Visual studio will compare the two schemas and display the results in a grid, showing you what objects (tables, views, procs, etc…) have changed and the action you want to take.

Select any item that has changed and you will see the differences between source and target.

The last pane at the bottom contains the update (migration) script that will run against the target to make it identical to the source.  You can quickly scan it to make sure you are not wiping out your entire production database (not recommended).

You can also customize the update by clicking the drop downs in the grid to customize the script

Once everything looks good to go, just hit the button "Write Updates" and you are done.

This has been a sore in my side for a long time and I am glad I discovered this.  I am actually kind of pissed off because I have always seen that menu and never really tried to click it.  Oh well!!!

Hmm…  What to do with all the time I just freed up???

NOTE: According to msdn this feature is only available in the Database Edition and Team Suite versions.  I am running Team Suite (click Help > About Microsoft Visual Studio to find out your version)

So, after several minutes of googling, I found several solutions that I didn’t like.  John Hann uses reflection to test private methods.  Tim Stall has a similar solution at the code project.  Andrew Stopford suggested that I don’t test private methods and use code coverage to make sure that they are being exercised.  I was about to use the methods suggested by John Hann and Tim Stall to test my private methods, but then I accidentally (thanks to IntelliSense) discovered PrivateObject.

The PrivateObject class is part of the Team Test API.

Allows test code to call methods and properties on the code under test that would be inaccessible because they are not public.
from msdn

It turned out to be pretty easy to test private methods and the code looked like this:

var myController = new TwitterController();
var po = new PrivateObject(myController);
var page = 1;
var count = 25;
po.Invoke("ImportTweets", new object[] { page, count });

The code above will call the private method ImportTweets and pass it two integer parameters.  This is the equivalent of calling

myController.ImportTweets( page, count);

Note that this is essentially what John Hann and Tim Stall suggested but why use extra code when PrivateObject is already available for you.

The sproc looked something like select id, name from mytable (I am over simplifying of course).  I was tasked to customize the export process, so that the user can select the columns/fields to be exported.  There were several constraints though:

1. Stored procedure should not change
2. Work within the existing export framework

The problem was that the existing framework used an Export function defined in a base class that all Exporters inherited.  The Export function expected a DataReader and simply exported whatever columns were in the reader.

One solution was to dynamically generate the SQL string in code and then execute it.  Another better solution was to use Dynamic LINQ.  Wait, but there is no such thing as dynamic LINQ, you say.  You are half right.  There is no built-in dynamic LINQ query generation into the framework but SOME GENIOUS created a bunch of extension methods to facilitate such a miraculous feat.

What is Dynamic LINQ? 

I hear you ask.  Let’s start by looking at regular (or static) LINQ, which looks like this:

var query = from person in people
            where person.City == "Arlington"
            select new
            {
                Id = person.Id,
                FirstName = person.FirstName
            };

This is static because there is no way to change the select so that it dynamically selects different attributes from the person class based on criteria specified by the user.  Also, for example, if you were creating an advanced search page and wanted the user to specify custom filter criteria, you won’t be able to dynamically generate the where conditions.

Dynamic LINQ, lets you do all these things and more.  Let’s take a look at a sample dynamic LINQ query:

people.Where("city = @0", "Arlington")
      .Select("new (Id, FirstName, LastName, State)");

So, I dynamically created the select using a collection of columns.  This is just a string collection that contains all the columns selected by the user to be exported.  The code looked like this:

string dynamicClass = string.Empty;
for (int i = 0; i < ColumnsToExport.Count; i++)
{
    string col = ColumnsToExport[i];
    if (i == 0)
    {
        dynamicClass = "new(" + col;
    }
    else
    {
        dynamicClass += "," + col;
    }
    if (i == ColumnsToExport.Count - 1)
    {
        dynamicClass += ")";
    }
}

All I have to do now is pass the dynamicClass string variable to the Select method.

Get Dynamic

To get dynamic LINQ in your project:

1. Copy Dynamic.cs file from C:\Program Files\Microsoft Visual Studio 9.0\Samples\1033\CSharpSamples\LinqSamples\DynamicQuery
2. If you don’t have that folder, click Help > Samples in Visual Studio and follow the instructions to install the samples
3. All you have to do is import the System.Linq.Dynamic namespace wherever you want to use Dynamic LINQ.

Let’s Reflect

I forgot to mention a few minor details.  The data to be exported is coming from a view.  The view is defined as a LINQ to SQL entity.

Ok, now that that’s out of the way, I needed to create a checkbox list of all the columns to allow the user to select the ones to export.  I obviously knew that this is doable using reflection, but had to dig around for the right calls to make.  All I needed to do is basically loop through all the properties of the LINQ to SQL entity class (the data class) for the view and bind them to the checkbox list control.  Here is the code:

   1: var props = typeof(PersonData).GetProperties();

   2: var columns = from prop in props

   3:               where prop.GetCustomAttributes(typeof(ExportableAttribute), false).Length > 0

   4:               select new ColumnCheckBoxItem

   5:               {

   6:                   DisplayName = (prop.GetCustomAttributes(typeof(ExportableAttribute), false)[0] as ExportableAttribute).DisplayName,

   7:                   PropertyName = prop.Name

   8:               };

   9:  

  10: clbColumns.DisplayMember = "DisplayName";

  11: clbColumns.ValueMember = "PropertyName";

  12: foreach (var column in columns)

  13: {

  14:     clbColumns.Items.Add(column);

  15: }

Let’s look at this code in more details.  In line 1, I get all the properties for my entity class PersonData.  Then I select only the properties that have the “Exportable” attribute.  This allowed me to filter out some properties from showing up in the checkbox list, such as timestamp and Guid columns.  For example the zip code is defined as a property called ZIP, but I wanted it to show up in the checkbox list as “Zip Code”, so I added a property to my ExportableAttribute class called DisplayName which allowed me to customize the diplay name.  So, the ZIP property looked like this:

[Column(Storage = "_ZIP", DbType = "NVarChar(100)")]
[Exportable(DisplayName = "Zip Code")]
public string ZIP
{
    get
    {
        return this._ZIP;
    }
    set
    {
        if ((this._ZIP != value))
        {
            this._ZIP = value;
        }
    }
}

In lines 4 to 8, I create an anonymous object that contains the display name and the actually property name which will respectively correspond to DisplayMember and ValueMember in the checkbox list (lines 10 and 11).

Note that in line 6, I retrieve all the attributes of the property that are of type ExportableAttribute.  This returns an array, so I use the first element to retrieve the DisplayName.  There is no need to test for null since the where condition will ensure that only properties with the Exportable attribute are included.

You are also probably wondering why I didn’t just set the checkbox list DataSource to the columns collection.  Well, I did an it didn’t bind correctly.  I am not sure why but the for loop worked and I didn’t want to waste too much time.  When I bound the list using the DataSource property, the checkboxes contained text like {DisplayMember = “Zip Code”, PropertyName=”ZIP”} instead of just containing Zip Code.  Does anyone know why?

Finally, the ExportableAttribute class looks like this:

public class ExportableAttribute : Attribute
{
    public string DisplayName;
}

The Export

Now that I have prompted the user to customize the export and I have dynamically built the LINQ query based of the user’s selection, all I have to do is export it.  As I mentioned above, the Export method in the base class needed a DataReader, so I had to convert my LINQ expression to a DataReader.  Here is how you get a DataReader out of a LINQ expression (note that this will work with both static and dynamic queries):

Database db = DatabaseFactory.CreateDatabase();
var cmd = context.GetCommand(query as IQueryable))
var myReader =  db.ExecuteReader(cmd);

As I read through these books, I realized there are lots of things I need to keep track of, that is lots of crumbs.  This series of blog posts are a way for me to keep track of these crumbs as well as share them with others.  I don’t plan to explain everything in detail (because I can’t).  This is more of a quick reference to remind me of features and things that I read about in the books because there is no FREAKING INTELLISENSE in rails.  You will realize how valuable Intellisense is when you don’t have it.

These crumbs are not in any specific order.  For the most part, they are in the order I discovered them.

content_tag

Use it to surround a block of text with a tag.  The code below creates <b>make me bold</b>

content_tag (:b, “make me bold”)

&block

I can’t find a good explanation of this but when you call a method from your views like this

<% my_foo() do %>
  [content]
<% end %>

And the method is defined like this

def my_foo(&block)
end

Then the &block parameter will contain all the text that is wrapped by this method in the view.  In the above example &block would contain [content]

blind_down

Use to generate a blind down effect in JavaScript to make hiding an element smoother than just setting display to none.  In you rjs template, write:

page[:element_id_to_blind].visual_effect :blind_down

request.xhr?

This returns true if the request is xhr i.e. an AJAX request.  I like the trailing question mark.  In .net, it would be named IsXhr.

has_many

Use in your model to create a relationship.  For example, an article model class might look like this

class Article < ActiveRecord::Base
has_many :categories
end

NOTE: your category model class name is Category but the has_many uses the actual table name which categories.  This is so weird for me – no compiler errors, no warnings, nothing.  I know, I know, convention over configuration.

belongs_to

Same idea as has_many but in reverse, so the category model class would look like this

class Category < ActiveRecord::Base
belongs_to :articles
end

button_to

A helper method that generates an HTML form containing a button that submits to a URL when clicked.  For example:

button_to “Edit”, :action => ‘edit’, :id => 3

Creates a form with an Edit button that submits to the edit action and pass 3 as an id parameter.  If we were editing an article, the generated html looks like this:

<form class=”button-to” action=”/articles/edit/3″ method=”post”>
    <div><input type=”submit” value=”Edit” /></div>
</form>

More crumbs to come – stay tuned.  Also feel free to add your own crumbs to the comments, it might help someone.

One thing I don’t like so far is the lack of good documentation for Rails 2.0 and there aren’t any books out there. I went ahead and bought me of Agile Web Development with Rails which has been updated for 2.0 but you can only get as beta from The Pragmatic Bookshelf. I bought the PDF version and have been reading it for the past few days.

It occurred to me that before I can get too deep into Rails, I need to learn a little about Ruby. After all the syntax is very different from C# or vb.net. Everyone claims that it is an easier language to understand but I think that is very subjective. Spanish might be easier than Chinese but if you are Chinese you might not think so.

With that said, in this post I am going to list a few things I have learned over the past few days about Ruby Syntax and how it compares to C# syntax.

Comments

C#

//this is a one line comment

/* This is a multi-line
comment
*/

Ruby

# this is a one line comment

=begin
this is a mult-line
comment
=end

Winner: C#

Class Definition

C#

class Car : Vehicle
{
public Car()
{
}
}

Ruby

class Car < Vehicle
def initialize
end
end

Winner: tie but if you hate curly brackets then Ruby wins

Method Definition

C#

public int GetYear()
{
}

public static int GetYear(string carName)
{
}

Ruby

def GetYear
end

def self.GetYear(carName)
end

Note: You can use the class name instead of self to make the method static. Also, in Ruby they are called class methods and not static methods. Come to think of it, that makes sense, since the method is defined for the class and not the instance or the object.

Winner: Ruby

Variables

Local variables

C#

int aNumber = 4; //declared inside a method

Ruby

aNumber=4 # no declaration needed just use it inside a method

Instance variables (fields)

C#

int aNumber; //declared inside a class not a method

Ruby

@aNumber #no declaration needed just use it anywhere

Static variables (fields)

C#

static int aNumber; //declared inside a class not a method

Ruby

@@aNumber #no declaration needed just it anywhere

Control Structure

if

C#

if (aCondition)
{
}
else
{
}

Ruby

if aCondition then
else
end

unless

C#

There is no unless in C# but the same logic can be written like this:

if (!aCondition)
{
}
else
{
}

Ruby

unless isBlue

else

end

case

C#

switch (year)
{
case 1960:
case 1961:
case 1962:
…
case 1969:
break;
case 1970:
…
case 1979:
break;
default:
}

The code above has been truncated for brevity because you cannot do ranges in C# as easy you can in Ruby

Ruby

case year
when 1960 .. 1969
when 1970 .. 1979
else
end

The above Ruby code is complete and not truncated. The express 1960 .. 1969 specifies a range.

while

C#

while (aCondition)
{
}

Ruby

while aCondition
end

until

C#

There is no until in C# but the same logic can be expressed like this:

while (!aCondition)
{
}

Ruby

until aCondition
end

This is not a comparison of language features, it is just a comparison of the syntactical differences of *some* of both languages. This is *not* an exhaustive list and is not meant to be – a simple Google search will get you thousands of pages of syntax goodies for either language.

So far, I can’t say I love Ruby’s syntax but if I were new to programming, I would say it looks more readable and easier to understand. Being a C#/VB developer for so long, I am a little confused and uncomfortable with the Ruby syntax. But, the facts that I have used VB for the past 10 or so years and that I hate semi-colons and curly brackets in C#, it is not that bad.

NOTE: forgive me if any of this is wrong, my RoR experience as of right now is 35 minutes…

Anyway, this post is not about the history of Ruby or a comparative analysis of which language or platform is better…  It is just a part of a series of blog posts that I will be writing as I learn more about RoR.  Everything is written from my perspective i.e. a 100% windows user and a .net developer.  So I am in foreign lands here.

The Setup

My current setup is a Mac Mini running Leopard with

The Environment

So after downloading all the RoR stuff from this website, I followed the steps and managed to create an empty application like this:

1. Open a terminal window 
2. Run rails /users/emad/code/favewares
3. Run cd path/to/your/new/application
4. Run ruby script/server

Then I opened http://localhost:3000 in my browser and got to the welcome page shown below.

Time to create the database, so I had to go download MySQL and install it which was surprisingly very straight forward:

1. Double click the MySQL installer
2. Double click the MySQL Startup Item installer

Then I ran into problems trying to get things going and quickly realized that being a windows user, I needed a GUI tool.  So I downloaded one from the MySQL website and installed it which was also pretty straight forward.  Until I tried to connect and got the error message “Can’t connect to local MySQL server through socket ‘/tmp/mysql.sock’ (2)”

After about an hour of trying different things and reading all sort of blogs and forums, I finally decided to restart my mac and voila, it worked…  At least Windows tells me that I need to restart.

Ok, so I got the GUI MySQL administrator up.  I added a database called favewares_development (to follow RoR naming conventions) and created some tables.

If you read anything about Rails you will end up reading the phrase “convention over configuration” a bazillion times; so here is a quick note on database naming conventions:

1. Database name = appname_development, appname_test, appname_production
2. Table name = plural e.g. authors, wares, stories, categories, etc…
3. Primary key name = id
4. Foreign keys = singularOfForeign_id e.g. category_id, author_id, etc…
5. Many to many tables = tablea_tableb in alphabetical order e.g. items_orders, classes_students

There is more information about Rails and Ruby naming conventions over here.

Database is now created, let’s edit the code.  Oops, no code editor – damn it.  I went to textmate and downloaded their 30-day trial.

Once I was done creating my tables, I generated the schema.rb file in the project’s db folder in textmate by clicking Bundles > Ruby on Rails > Database > Dump DB to schema.rb

My scheam.rb file looked like this:

Although I didn’t really have much so far, my brain had had enough of being outside its comfort zone – I miss windows… 

Stay tuned for the next part of this post.

[update] Part 2 is available here.

I commented all the changes made in the code and prefixed them with //emad. So just search for //emad and you will see all the changes I made… Here is a quick list of the changes I made to make this compile and run on MVC Preview 2:

1. Removed the [ControllerAction] tags – they are no longer needed.
2. Updated the Route Table creation in the global.asax.cs file to work with the new format
3. Updated the Ajax framework project to use the new classes
   1. HttpContextBase instead of IHttpContext
   2. HttpRequestBased instead of IHttpRequest
   3. HttpResponseBase instead of IHttpResponse
4. Updated the AjaxViewContext constructor to match ViewContext constructor
5. Changed the web.config to work with the new version (copied and pasted from another preview 2 project)

Note: Test project was not updated and will not compile – sorry, I didn’t have time to do it.

Here is the updated code: tasklist.zip

And you want to animate rectRed by sliding it out from the right side, without clipping it would look like this

But if you set the Clip property on the blue rectangle to equal its dimension then it would look like this

You can set the clip in code-behind like this:

RectangleGeometry recClip =  new RectangleGeometry();
recClip.Rect = new Rect(0, 0, recBlue.ActualWidth, recBlue.ActualHeight);
pnlContent.Clip = recClip;

This works in both Silverlight and WPF.

I attached this style to a button

<Style x:Key="NavButtonStyle" TargetType="Button">
    <Setter Property="Opacity" Value="0.8"></Setter>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate>
                <Grid x:Name="RootElement" 

                     HorizontalAlignment="Stretch" 

                     VerticalAlignment="Stretch">
                    <ContentPresenter 

                        Content="{TemplateBinding Content}"/>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Everything compiled fine but the page wouldn’t look right and expression blend would not display it correctly and would display the error message:

The member “Content” is not recognized or is not accessible.

I have not idea how I figured out but it turns out that all I had to do is add a TargetType to the ControlTemplate…  I don’t understand why I have to do this since I already set the TargetType on the Style element…  Anyone?

The final style looked like this:

<Style x:Key="NavButtonStyle" TargetType="Button">
    <Setter Property="Opacity" Value="0.8"></Setter>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Button">
                <Grid x:Name="RootElement" 

                     HorizontalAlignment="Stretch" 

                     VerticalAlignment="Stretch">
                    <ContentPresenter 

                        Content="{TemplateBinding Content}"/>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>