It's tempting to just leave this blog post with that statement only I will however explain this a bit further for those of you who either are forced to write comments (like by your boss or a policy at your company), or actually believe a lot of comments in code increase readability and ease maintenance.

I'm not trying to be sarcastic, I just believe 100% in code and not in comments. In .NET and most other OO languages there are two types of comments. The first type is the one you write in your code to explain what your code does. Like this:

//Calculate interest
double amount 
    = balance * Math.Pow(1 + (annualPercentage / 100) / 365, days)
      - balance;

How do you replace this comment with code? What about this:

double amount = CalculateInterest(balance, annualPercentage, days);

Whenever you come across comments like the above, I encourage you to refactor by replacing comments with code. Often you don't even have to extract a method like above, but just give better names to variables.

The second type of comments is the ones you use to generate API documentation:

/// <summary>
/// Calculate interest
/// </summary>
/// <param name="balance">Current balance of the account</param>
/// <param name="annualPercentage">Annual percentage</param>
/// <param name="days">Days to calculate interest for</param>
/// <returns>Interest amount</returns>
public double CalculateInterest(double balance, 
                                double annualPercentage, 
                                int days)
{

Almost on every project I've been on we've had these comments/documentation. Also, on the same projects they've never been used for anything useful. I've actually forced devs to do this myself! If you're creating a product/framework to be used by other devs, writing this type of documentation makes sense. If you don't, it makes no sense! I used to do this just to satisfy my own satisfaction of generating a chm file and see that all my methods and classes was documented. That was about it. I never used it once! It's much easier to look in the code than to look at the API doc.

The worst thing about this type of documentation is that it clutters your code and makes the code hard to read. A class with 50 lines of code becomes 100 lines with comments. As a practice, try to remove all comments and see if it's easier to understand and read the class. I strongly believe it is. If not, it's a code smell and you should refactor your code! Comments should not be used to explain bad code.

When I talk to people about comments in code I often ask them two questions:

Do you think it's hard to maintain code?

How hard to you think it is to maintain comments?

If you change your code, do you also make sure to check if the comments are still correct after you've done the changes? Most people don't and you shouldn't really need to worry about it. Outdated comments can create confusion and bugs just because someone forgot to update them.

At QCon London 2009, Dan Bergh Johnsson had a talk on the DDD track about how to make use of Value Objects (VO's) (The Power of Value - Power Use of Value Objects in Domain Driven Design (PDF)). In his talk he took a piece of code and refactored it into a better piece of code by using VO's. By doing this Dan showed some really good concepts of using VO's. Even though I knew about the concept of VO's before his talk, he made me realize many new scenarios where they are applicable. And more importantly that it is not limited to DDD.

So what is a VO anyway? Is it related to value type in .NET?

To answer the last question first: The real answer is no, but the way I see it there is a relation. A value type in .NET is everything that is not an object. Typically simple types like int, char, double, but also enums and structs. The relation is that often you find yourself creating VO's where value types was previously used. It is however not limited to value types.

Now to the first question. I first came across VO's after reading Evans DDD book (commonly known as the blue book). In DDD a Value Object is an object without an Id and are usually immutable. In examples of VO's, Address is commonly used, which I don't find particularly useful. I think Address way too often has an Id and people have a hard time relating to that as a Value Object. I find the Amount example I gave in an earlier post to a better example or the one below illustrated as an interface (borrowed from Dan):

public interface IPhoneNumber {
  bool IsValid {get;}
  string Number {get;}
  string AreaCode {get;}
}

How many times have you used the concept of a phone number in your code? Like mobile, fax, fixed etc… How often have you kept it as a string? How much code do you have for doing different types of validation, getting area code etc? Do you have it all in one place or scattered around in different places? Other examples are Money, ZipCode etc… These are great candidates for Value Objects.

Now that we know what Value Objects are, what is so powerful about them and why should I use them more? Great question Below is my three reasons:

1. Code readability - I find that using Value Objects greatly improve the overall code readability and eliminates comments. Just like good names on methods and properties does.
2. DRY (Don't Repeat Yourself) - By having a Value Object for PhoneNumber, you avoid writing code to handle specific cases around phone numbers and you reuse them wherever the concept of a phone number is used.
3. Helps people getting back into OO thinking – We who have been living in the Microsoft .NET world for a long time have been thought to think of programming from a data/database perspective and not object oriented programming as we once learned it. In other words: think of behavior instead of data.

When I started to use VO's, I soon discovered I used them all over. They really add great value to my code. As an example, lets implement the IPhoneNumber above:

public class PhoneNumber : IPhoneNumber
{
    private readonly string _phoneNumber;
    public PhoneNumber(string phoneNumber)
    {
        _phoneNumber = phoneNumber;
    }
    public bool IsValid
    {
        get { return Regex.IsMatch(_phoneNumber, @"^[01]?[- .]?(\([2-9]\d{2}\)|[2-9]\d{2})[- .]?\d{3}[- .]?\d{4}$"); }
    }
    public string Number
    {
        get { return _phoneNumber; }
    }
    public string AreaCode
    {
        get
        {
            return Regex.Match(_phoneNumber, @"^[01]?[- .]?(\([2-9]\d{2}\)|[2-9]\d{2})").ToString();
        }
    }
}

The above code handles US phone numbers. To be used in a production system there should probably be even more validation in the regexp's, but I hope the example gives you and idea of what I'm thinking.

One of the code smells I see most often in C# and other OO languages is the misuse of switch/case statements. When I was a young Jedi (some might argue I still am ) I didn't see anything wrong with using the switch statement. Actually there still are a few cases where it's still applicable, but most usages I come across should have been solved differently. So why is this? What is so bad with the switch statement?

As Dan North tweeted me when I asked for the perfect refactoring solution for switch statements :

A switch is often a sign of behaviour that should live elsewhere - so where should the code in the cases live?

Functions should only do one thing, the one thing which they state. Like CalculateInterest and ConvertDateToString should do exactly that; calculate interest and convert a date to string. Since switch always reside inside functions it almost always violates that principle.

Let's look at what Uncle Bob (Robert C. Martin) says in his Clean Code book about switch statements:

Even a switch statement with only two cases is larger than I'd like a single block or function to be. It's also hard to make a switch statement that does one thing. By their nature, switch statements always do N things.

My answer to Dan's question above was using polymorphism. The cases should live in their own classes. By doing that you don't have to modify existing code when introducing new behavior, you just create a new state (read class). Btw Dan is really good at asking questions to questions where you end up answering your own question

Enough with the coding theory. Below is a method using a switch statement for getting messages from different systems. Typically these are systems that another system depends on (the system containing the below code). The messages might be if the system is available or not, or if there are any maintenance planned.

public string GetSystemMessage(System system)
{
    switch (system)
    {
        case System.System1:
            return GetSystem1Message();
        case System.System2:
            return GetSystem2Message();
        case System.System3:
            return GetSystem3Message();
        case System.System4:
            return GetSystem4Message();
        default:
            throw new ApplicationException("System not found");
    }
}

This is actually quite a good switch. It uses return instead of break and it only has one line per case. If you can't avoid writing a switch, this is how you should do it.

Now let's pull it apart and make it better and extendable. Time for refactoring.

Polymorphism by using Strategy Template Pattern
Here's my code using the Strategy pattern:

public interface ISystemStrategy
{
    string GetMessage();
}
public class System1Strategy : ISystemStrategy
{
    public string GetMessage()
    {
        return "System1";
    }
}
public class System2Strategy : ISystemStrategy
{
    public string GetMessage()
    {
        return "System2";
    }
}
public class System3Strategy : ISystemStrategy
{
    public string GetMessage()
    {
        return "System3";
    }
}
public class System4Strategy : ISystemStrategy
{
    public string GetMessage()
    {
        return "System4";
    }
}
public class SystemMessenger
{
    private readonly ISystemStrategy _system;
    public SystemMessenger(ISystemStrategy system)
    {
        _system = system;
    }
    public string GetMessage()
    {
        return _system.GetMessage();
    }
{
}

First I define an interface to be used by the different systems (ISystemStrategy) and next each system (1-4) implements that interface, resulting in a class for each case in the switch.In addition I have a class called SystemMessenger that is responsible for accessing the system and get a message.

The switch can now be replaced by this code:

public string GetSystemMessage(ISystemStrategy system)
{
    return new SystemMessenger(system).GetMessage();
}

Note that the "client" only relates to the SystemMessenger class and not to the different implementations of ISystemStrategy.

The benefit of this code might not be obvious. Actually it might give the impression that this was a lot of code for almost nothing. Well, don't be fooled. The strongest aspect of the above solution is that you don't have to change the GetSystemMessage later when/if a new system is added, you just implement a new class.

To prove the above, here's what I need to do to introduce a new system:

public class System5 : ISystemStrategy
    public string GetMessage()
    {
        return "System5";
    }
}

To use the new system, an instance of System5 will be sent into GetSystemMessage just as before, and SystemMessenger handles the rest as before. No code change!

Dictionary
Another refactoring option is using some type of lookup table. In my example I'll use a dictionary together with the Func<TResult> delegate. However, I don't recommend doing this unless you have a really good reason to do so. Stick with the Strategy pattern if you can.

public class SystemMessengerDictionary
{
    private readonly Dictionary<System, Func<string>> _systems;
    public SystemMessengerDictionary()
    {
        _systems = new Dictionary<System, Func<string>>
                           {
                               {System.System1, GetSystem1Message},
                               {System.System2, GetSystem2Message},
                               {System.System3, GetSystem3Message},
                               {System.System4, GetSystem4Message}
                           };
    }
    public string GetSystemMessage(System system)
    {
        return _systems[system]();
    }
    //GetSystemX Methods
    ...
}

I decided to show this example even if I don't like it. The reason is that it is better than the switch. The worst about this in my eyes is that the enum is still there. I just hate enums! When reading the code they look like classes with interesting behavior, but then you discover they're just glorified int's :-|

Conclusion
Hopefully this example will help you understand why switch is something you should avoid and also give you an example of how it should be done. But before you consider doing any refactoring of existing code, consider a second question Dan asked (answered?) me:

How would it evolve if you added a few more cases? And how likely are a few more cases?

This is an important question, because you don't want to refactor just for the sake of refactoring. Keep this in mind before making use of any of the suggested solutions above.

Recently I worked with a colleague on some code using decimal.TryParse() and tried to find a better way of using it. Specifically I had a string value representing a currency amount entered by a user in a web form. The amount needed more than just normal validation, so I needed to do some stuff with it.

Here's the code I started with:

public void SomeMethod(string userEnteredAmount)
{
    decimal amount;
    if(decimal.TryParse(userEnteredAmount, out amount) {
        //Do some stuff with amount
    }
    else {
        //Show message to user about invalid amount
    }
}

I've recently found many cases where I find the use of Value Objects to be very applicable. I found this case to be a particularly interesting example. Anyway, I created a Value Object called Amount to abstract away the TryParse stuff. Below is the class I created.

public class Amount
{
    private readonly decimal _value;
    private readonly bool _isValid;
    public Amount(string amount)
    {
        _isValid = decimal.TryParse(amount, out _value);
    }
    public decimal Value
    {
        get { return _value; }
    }
    public bool IsValid
    {
        get { return _isValid; }
    }
}

See how clean it got? At least I think so. The important part though is that it's usage is so much easier to understand and read:

var amount = new Amount(userEnteredAmount);
if(amount.IsValid) {
    //Do some stuff with amount.Value
}
else {
    //Show message to user about invalid amount
}

It's more code, but cleaner. Or did I say that already? And of course it's reusable other places where amount has a meaning.

My article about The Future of Microsoft .NET Programming Languages just got published on InfoQ.This is my first attempt at being an editor for them, so if this works out I hope you will see more stuff from me in the near future.

Would love to hear what you think, so drop me a comment if you like.

This is my fourth post in my WiX and DTF series. Here are some others I’ve written:

• An introduction 
• Using WiX to author MSI installations
• Using a bootstrapper to force elevated privileges in Vista
• Debug a Managed Custom Action and how to generate an MSI log

Intro

In this article I’ll cover how to allow a user to choose which web site to install an application to by listing available web sites in a list box in the MSI installation wizard. As mention in my previous articles I'm applying best practices (at the best of my knowledge) to have the installer pass the Vista certification, so hopefully that will be the case if you use any of this in production

When doing lookups in IIS using custom actions in the InstallUISequence (as we need to do in order to get available web sites), elevated privileges is required (at least in Vista SP1). This means we need the installation to run as admin. This is also an issue in the WiX extension for IIS as described in this bug report. See my previous article of a workaround for both the UI Sequence part and the bug: Using a bootstrapper to force elevated privileges in Vista

If you did not quite understand what I just said about the sequence stuff, elevated privileges etc., relax and keep reading, you will know by the end of this post and/or by clicking the link above

Overview

This article assume you’ve read my previous article about Using WiX to author MSI installations or that you are somewhat familiar with WiX. If you haven’t done so already and want to follow this article step-by-step, download the WiX project from my previous article here: SimpleWebApp.zip

There is another possibility of course If you’re lazy and just want the complete source for this article, you can download everything from here: SimpleWebApp_WSSelect.zip

Since this article became rather long I’ve structured it into 3 main sections with related sub sections, which hopefully will help you later if you need to look up something:

• Custom Actions
  • Get web sites
  • Add selected web site info to properties
• Create a new dialog
• Changes to Product.wxs (the main WiX file)
  • Custom Table - Storing web site info
  • Properties: Define, store and retrieve
  • Reference CA’s
  • Change the WebSite standard action
  • The complete Product.wxs
  • The End!

Now let’s dig into it!

Custom actions

To add a CA to your solution, do this:

1. Add a new class library project to your solution and name it IISCustomAction
2. Add a reference to Microsoft.Deployment.WindowsInstaller found in the WiX SDK
3. Add a reference to System.DirectoryServices
4. Rename the class created by VS to CustomAction.cs
5. Add the following using’s to CustomAction.cs:
   1. using System.DirectoryServices;
   2. using Microsoft.Deployment.WindowsInstaller;

When building your project a couple of things happens:

• The managed dll (IISCustomAction.dll) is created as expected by a class library
• MakeSfxCA.exe (which is automatically called when building in VS) is creating a new dll based on the managed dll named IISCustomAction.CA.dll (this is the one you need to use in your WiX project)

It’s MakeSfxCA.exe that does all the magic here. The output dll that MakeSfxCA has created is actually a Win32 DLL. Here’s what Christopher Painter says about this:

At runtime, MSI thinks it’s calling a Win32 DLL in it’s own sandbox but in reality the CLR is being fired up out of process and communicated with through a named pipe.

Read the complete article here.

A typical CA looks something like this:

[CustomAction]
public static ActionResult MyCustomAction(Session session)
{
    try
    {
        ...
    }
    catch (Exception ex)
    {
        session.Log("CustomActionException: " + ex.ToString());
        return ActionResult.Failure;
    }
    return ActionResult.Success;
}

The [CustomAction] attribute is needed to tag this method as a CA. The ActionResult returns either (in my case) Failure or Success allowing the installer to respond accordingly. The parameter for this method is a Session object. This object gives me access to the MSI database and the inner workings of Windows Installer allowing me to query the database, access MSI properties etc.

Now you have what you need to start writing CA’s for the Windows Installer, so let’s get cranking.

Custom action – Get web sites
Copy and paste the code below into the CustomAction.cs class in the project you created above:

[CustomAction]
public static ActionResult GetWebSites(Session session)
{
    try
    {
        View listBoxView = session.Database.OpenView("select * from ListBox");
        View availableWSView = session.Database.OpenView("select * from AvailableWebSites");
        DirectoryEntry iisRoot = new DirectoryEntry("IIS://localhost/W3SVC");
        int order = 1;
        foreach (DirectoryEntry webSite in iisRoot.Children)
        {
            if (webSite.SchemaClassName.ToLower() == "iiswebserver" && 
                webSite.Name.ToLower() != "administration web site")
            {
                StoreWebSiteDataInListBoxTable(webSite, order, listBoxView);
                StoreWebSiteDataInAvailableWebSitesTable(webSite, availableWSView);
                order++;
            }
        }
    }
    catch (Exception ex)
    {
        session.Log("CustomActionException: " + ex.ToString());
        return ActionResult.Failure;
    }
    return ActionResult.Success;
}

Here’s what I’ve done in the code above:

• Open two views to the msi database. One for the ListBox table and one for a custom table which I will cover later called AvailableWebSites.
• Get the root entry in IIS by using an LDAP query.
• Iterate every child of the web site to get and store the information I need.

Here’s the code for the two helper methods I use to store the IIS data to the Windows Installer database:

private static void StoreWebSiteDataInListBoxTable(DirectoryEntry webSite, int order, View listBoxView)
{
    Record newListBoxRecord = new Record(4);
    newListBoxRecord[1] = "WEBSITE";
    newListBoxRecord[2] = order;
    newListBoxRecord[3] = webSite.Name;
    newListBoxRecord[4] = webSite.Properties["ServerComment"].Value;
    listBoxView.Modify(ViewModifyMode.InsertTemporary, newListBoxRecord);
}
private static void StoreWebSiteDataInAvailableWebSitesTable(DirectoryEntry webSite, View availableWSView)
{
    //Get Ip, Port and Header from server bindings
    string[] serverBindings = ((string)webSite.Properties["ServerBindings"].Value).Split(':');
    string ip = serverBindings[0];
    string port = serverBindings[1];
    string header = serverBindings[2];
    Record newFoundWebSiteRecord = new Record(5);
    newFoundWebSiteRecord[1] = webSite.Name;
    newFoundWebSiteRecord[2] = webSite.Properties["ServerComment"].Value;
    newFoundWebSiteRecord[3] = port;
    newFoundWebSiteRecord[4] = ip;
    newFoundWebSiteRecord[5] = header;
    availableWSView.Modify(ViewModifyMode.InsertTemporary, newFoundWebSiteRecord);
}

The first method stores data in the ListBox table and the second in my custom AvailableWebSites table.

My custom table (which I’ll explain in more detail later) contains the following columns:

• WebSiteNo
• WebSiteDescription
• WebSitePort
• WebSiteIP
• WebSiteHeader

The ListBox table has these four columns:

• Property
• Order
• Value
• Text

For the ListBox table the Property is used for identifying one specific list box and will allow you to get the Value of the selected item later. The Property must be the same for every record that you want displayed in one single UI list box. Order defines in which order the item are displayed in the list. Value is what’s being returned to you when accessing the property later on. The Text field is what is shown in the UI list box that the end user sees in the MSI wizard.

In my code I set the Property for all records to WEBSITE. The Order is set to 1 the first time and then incremented by 1 every iteration. The Value is set to the web site id and theText is set to the web site name.

After the user have selected the web site we can find out which one by using the WEBSITE property, which will give us the id of the web site (the Value field).

In my custom AvailableWebSites table I store some more details about every web site. But before I can do that I need to get the server bindings from IIS which is formatted like this: ip:port:header. I split these up and add them to to the database. I do the same with WebSiteNo and WebSiteDescription.

In both cases I store the values to the record and update the database (using modify). Note that you have to use InsertTemporary because you’re not allowed to write permanent data to the MSI database during installation.

Custom action – Add selected web site info to properties
After the user have selected a web site in the list box, I call a CA where I store the details about the web site to some public properties. This will make more sense later when we stitch everything together in the WiX product file, but for now here’s the code:

[CustomAction]
public static ActionResult UpdatePropsWithSelectedWebSite(Session session)
{
    try
    {
        string selectedWebSiteId = session["WEBSITE"];
        session.Log("CA: Found web site id: " + selectedWebSiteId);
        View availableWebSitesView = session.Database.OpenView("Select * from AvailableWebSites where WebSiteNo=" + selectedWebSiteId);
        availableWebSitesView.Execute();
        Record record = availableWebSitesView.Fetch();
        if ((record[1].ToString()) == selectedWebSiteId)
        {
            session["WEBSITE_DESCRIPTION"] = (string)record[2];
            session["WEBSITE_PORT"] = (string)record[3];
            session["WEBSITE_IP"] = (string)record[4];
            session["WEBSITE_HEADER"] = (string)record[5];
        }
    }
    catch(Exception ex)
    {
        session.Log("CustomActionException: " + ex.ToString());
        return ActionResult.Failure;
    }
    return ActionResult.Success;
}

Remember the id for the web site that the user selected is stored in the WEBSITE property in the ListBox table? I can get this value by calling session[“WEBSITE”]. I then query my custom table that I populated earlier for details about this web site using Select with the id of the web site in the where clause. I then store these values to the properties: WEBSITE_DESCRIPTION, WEBSITE_PORT, WEBSITE_IP and WEBSITE_HEADER. These properties and where they came from will be explained later

Create a new dialog

To have the user see and select from available web sites, we need to create a dialog displaying a list box. Add a new wxs file to your project and name it SelectWebSiteDlg.wxs. Then replace any generated xml with this xml:

<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
  <Fragment>
    <CustomAction Id="UpdatePropsWithSelectedWebSite" BinaryKey="WebSiteCA" DllEntry="UpdatePropsWithSelectedWebSite" Execute="immediate" Return="check" />
    <Binary Id="WebSiteCA" SourceFile="$(var.SolutionDir)\IISCustomAction\bin\Debug\IISCustomAction.CA.dll" />
  </Fragment>
  <Fragment>
    <UI>
      <Dialog Id="SelectWebSiteDlg" Width="370" Height="270" Title="Select Web Site">
        <Control Id="Next" Type="PushButton" X="236" Y="243" Width="56" Height="17" Default="yes" Text="!(loc.WixUINext)" />
        <Control Id="Back" Type="PushButton" X="180" Y="243" Width="56" Height="17" Text="!(loc.WixUIBack)" />
        <Control Id="Cancel" Type="PushButton" X="304" Y="243" Width="56" Height="17" Cancel="yes" Text="!(loc.WixUICancel)">
          <Publish Event="SpawnDialog" Value="CancelDlg">1</Publish>
        </Control>
        <Control Id="Description" Type="Text" X="25" Y="23" Width="280" Height="15" Transparent="yes" NoPrefix="yes" Text="Please select which web site you want to install to." />
        <Control Id="Title" Type="Text" X="15" Y="6" Width="200" Height="15" Transparent="yes" NoPrefix="yes" Text="Select Web Site" />
        <Control Id="BannerBitmap" Type="Bitmap" X="0" Y="0" Width="370" Height="44" TabSkip="no" Text="!(loc.InstallDirDlgBannerBitmap)" />
        <Control Id="BannerLine" Type="Line" X="0" Y="44" Width="370" Height="0" />
        <Control Id="BottomLine" Type="Line" X="0" Y="234" Width="370" Height="0" />
        <Control Id="SelectWebSiteLabel" Type="Text" X="20" Y="60" Width="290" Height="14" NoPrefix="yes" Text="Select web site:" />
        <Control Id="SelectWebSiteCombo" Type="ListBox" X="20" Y="75" Width="200" Height="150" Property="WEBSITE" Sorted="yes" />
      </Dialog>
    </UI>
  </Fragment>
</Wix>

This xml file is separated into two fragments; one for the CA and one for the actual UI. The CA entry define in which assembly the CA is located and defines an id we can use later when calling the CA. This CA is the one I created previously for updating some properties with IIS data. The reason I’m defining it here is that I can, and it makes sense to group it with the dialog that are using it. Because, as you will see later, we’re going to call this CA after the user have clicked next on this dialog.

The UI section is where the layout of the actual UI components is defined. Most elements are default for any dialog, except SelectWebSiteLabel and SelectWebSiteCombo which is the two controls specific to the web site dialog.

I also need to update MyUI.wxs which controls which and in which order the dialogs are displayed in the wizard. I’ve added the SelectWebSiteDlg between InstallDirDlg and VerifyReadyDlg as shown here:

<Publish Dialog="InstallDirDlg" Control="Next" Event="SetTargetPath" Value="[WIXUI_INSTALLDIR]" Order="1">1</Publish>
<Publish Dialog="InstallDirDlg" Control="Next" Event="DoAction" Value="WixUIValidatePath" Order="2">1</Publish>
<Publish Dialog="InstallDirDlg" Control="Next" Event="SpawnDialog" Value="InvalidDirDlg" Order="3"><![CDATA[WIXUI_INSTALLDIR_VALID<>"1"]]></Publish>
<Publish Dialog="InstallDirDlg" Control="Next" Event="NewDialog" Value="SelectWebSiteDlg" Order="6"><![CDATA[WIXUI_INSTALLDIR_VALID="1"]]></Publish>
<Publish Dialog="InstallDirDlg" Control="ChangeFolder" Property="_BrowseProperty" Value="[WIXUI_INSTALLDIR]" Order="1">1</Publish>
<Publish Dialog="InstallDirDlg" Control="ChangeFolder" Event="SpawnDialog" Value="BrowseDlg" Order="2">1</Publish>
<Publish Dialog="SelectWebSiteDlg" Control="Next" Event="DoAction" Value="UpdatePropsWithSelectedWebSite" Order="1">1</Publish>
<Publish Dialog="SelectWebSiteDlg" Control="Next" Event="NewDialog" Value="VerifyReadyDlg" Order="2">1</Publish>
<Publish Dialog="SelectWebSiteDlg" Control="Back" Event="NewDialog" Value="InstallDirDlg" Order="1">1</Publish>
<Publish Dialog="VerifyReadyDlg" Control="Back" Event="NewDialog" Value="SelectWebSiteDlg" Order="1">NOT Installed</Publish>
<Publish Dialog="VerifyReadyDlg" Control="Back" Event="NewDialog" Value="MaintenanceTypeDlg" Order="2">Installed</Publish>

See that I use DoAction to call the CA I defined earlier? This is how you hook up a CA to the “click event” of a button (or any control for that matter). Not quite as easy as in Win Forms, but it’s still quite logical.

Also note that I’ve changed the Next event for InstallDirDlg and the Back event for VerifyReadyDlg to point to my new dialog. This so the wizard will navigate correctly when the user clicks the next and back buttons.

Changes to Product.wxs (the main WiX file)

Custom Table – Storing web site info
I promised to cover my custom table in more detail later, so here it is. First the code:

<CustomTable Id="AvailableWebSites" >
  <Column Id="WebSiteNo" Category="Identifier" PrimaryKey="yes" Type="int" Width="4" />
  <Column Id="WebSiteDescription" Category="Text" Type="string" PrimaryKey="no"/>
  <Column Id="WebSitePort" Category="Text" Type="string" PrimaryKey="no"/>
  <Column Id="WebSiteIP" Category="Text" Type="string" PrimaryKey="no" Nullable="yes"/>
  <Column Id="WebSiteHeader" Category="Text" Type="string" PrimaryKey="no" Nullable="yes"/>
  <Row>
    <Data Column="WebSiteNo">0</Data>
    <Data Column="WebSiteDescription">Bogus</Data>
    <Data Column="WebSitePort">0</Data>
    <Data Column="WebSiteIP"></Data>
    <Data Column="WebSiteHeader"></Data>
  </Row>
</CustomTable>

When a user have selected the web site to install to, instead of querying IIS for details about the web site (web site number, description, port etc), I can just get it from my AvailableWebSite table. Note that I’ve added some dummy data in the first row. Without this the custom table was not stored to the MSI and I did not find any other way of getting this to work.

Properties: Define, store and retrieve
Earlier I created a CA that stored info about the selected web site into some public properties. Where did these properties come from? Well, they’re defined in the Product.wxs file like this:

<Property Id="WEBSITE_DESCRIPTION">
  <RegistrySearch Id="WebSiteDescription"
          Name="WebSiteDescription"
          Root="HKLM"
          Key="SOFTWARE\torresdal.net\SimpleWebApp\Install"
          Type="raw" />
</Property>
<Property Id="WEBSITE_PORT">
  <RegistrySearch Id="WebSitePort"
          Name="WebSitePort"
          Root="HKLM"
          Key="SOFTWARE\torresdal.net\SimpleWebApp\Install"
          Type="raw" />
</Property>
<Property Id="WEBSITE_IP">
  <RegistrySearch Id="WebSiteIP"
          Name="WebSiteIP"
          Root="HKLM"
          Key="SOFTWARE\torresdal.net\SimpleWebApp\Install"
          Type="raw" />
</Property>
<Property Id="WEBSITE_HEADER">
  <RegistrySearch Id="WebSiteHeader"
          Name="WebSiteHeader"
          Root="HKLM"
          Key="SOFTWARE\torresdal.net\SimpleWebApp\Install"
          Type="raw" />
</Property>

I’ve also defined a registry search within each property. Why? In order to have access to these values during e.g. repair or uninstall we need to store them in the registry for later use. Why? Well, the Windows Installer does not maintain state (except from INSTALLDIR and maybe a few others). Meaning any values or selections a user did during installation is not kept for later use. Since we will need to know which web site the user installed the application to, so we can remove it on uninstall, we need to store the state to the registry. If the application has been installed before, the registry search above get’s these values from the registry and stores them in their respective properties.

But how did they end up in the registry to begin with? I do that by defining a new component like this:

<Component Id="PersistWebSiteValues" Guid="C3DAE2E2-FB49-48ba-ACB0-B2B5B726AE65">
  <RegistryKey Root="HKLM" Key="SOFTWARE\torresdal.net\SimpleWebApp\Install">
    <RegistryValue Name="WebSiteDescription" Type="string" Value="[WEBSITE_DESCRIPTION]"/>
    <RegistryValue Name="WebSitePort" Type="string" Value="[WEBSITE_PORT]"/>
    <RegistryValue Name="WebSiteIP" Type="string" Value="[WEBSITE_IP]"/>
    <RegistryValue Name="WebSiteHeader" Type="string" Value="[WEBSITE_HEADER]"/>
  </RegistryKey>
</Component>

And we need to reference the component under the Feature tag:

<ComponentRef Id="PersistWebSiteValues" />

Registry key’s in WiX require a component, which is good. That means that these keys/values will be added on install and removed on uninstall, saving us manual work. The registry key above is created at SOFTWARE\torresdal.net\SimpleWebApp\Install. The actual values are the properties as you see in the Value attributes. To reference a property just use [MY_PROPERTY]. This comes in handy many times when authoring MSI installations.

Reference CA’s
One of the CA’s (the UpdatePropsWithSelectedWebSite) is actually already referenced in the SelectWebSiteDlg, but we need to reference the GetWebSites CA as well:

<CustomAction Id="GetIISWebSites" BinaryKey="IISCA" DllEntry="GetWebSites" Execute="immediate"  Return="check" />
<Binary Id="IISCA" SourceFile="$(var.SolutionDir)IISCustomAction\bin\Debug\IISCustomAction.CA.dll" />

The CustomAction tag defines a logical entry that we can use later to call this CA by using the id GetIISWebSites. In addition there is a Binary node that tells where WiX can find this CA when build the project. The CustomAction node point to this by using the BynaryKey attribute.

Then we need to make sure it’s being called:

<InstallUISequence>
  <Custom Action="GetIISWebSites" After="CostFinalize" Overridable="yes">NOT Installed</Custom>
</InstallUISequence>

The above code tells the installer to run this CA in the UISequence only when the application is not already installed (defined by the NOT Installed condition).

Change the WebSite standard action
In order for the installer to pick up the properties we’ve set for the selected web site (description, port, ip etc) we need to change the code we had previously:

<iis:WebSite Id='DefaultWebSite' Description='Default Web Site'>
    <iis:WebAddress Id='AllUnassigned' Port='80' />
</iis:WebSite>

To this:

<iis:WebSite Id="SelectedWebSite" Description="[WEBSITE_DESCRIPTION]">
  <iis:WebAddress Id="AllUnassigned" Port="[WEBSITE_PORT]" IP="[WEBSITE_IP]" Header="[WEBSITE_HEADER]" />
</iis:WebSite>

Makes sense right? I’ve also changed the id to SelectedWebSite which is more accurate in this case, meaning you need to update the WebSite reference in WebVirtualDir in the IISAppplication component as well. If you fail to do this the WiX compiler will complain, so you’re in safe hands

The complete Product.wxs
There’s a lot of snippets above, so for your convenience I’ve included the complete code for Product.wxs here so you see everything together:

<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi" xmlns:util="http://schemas.microsoft.com/wix/UtilExtension" xmlns:iis="http://schemas.microsoft.com/wix/IIsExtension">
  <Product Id="77da05c4-1644-4bc3-ac14-c0f721fe31fe" Name="Simple Web App" Language="1033" Version="1.0.0.0" Manufacturer="Jon Torresdal" UpgradeCode="a897ccc5-1c81-47e0-a837-65c07a72a7bc">
    <Package InstallerVersion="400" Compressed="yes" />
    <Media Id="1" Cabinet="WixProject1.cab" EmbedCab="yes" />
    <Property Id="TARGETVDIR" Value="SimpleWebApp"/>
    <Property Id="WEBSITE_DESCRIPTION">
      <RegistrySearch Id="WebSiteDescription"
              Name="WebSiteDescription"
              Root="HKLM"
              Key="SOFTWARE\torresdal.net\SimpleWebApp\Install"
              Type="raw" />
    </Property>
    <Property Id="WEBSITE_PORT">
      <RegistrySearch Id="WebSitePort"
              Name="WebSitePort"
              Root="HKLM"
              Key="SOFTWARE\torresdal.net\SimpleWebApp\Install"
              Type="raw" />
    </Property>
    <Property Id="WEBSITE_IP">
      <RegistrySearch Id="WebSiteIP"
              Name="WebSiteIP"
              Root="HKLM"
              Key="SOFTWARE\torresdal.net\SimpleWebApp\Install"
              Type="raw" />
    </Property>
    <Property Id="WEBSITE_HEADER">
      <RegistrySearch Id="WebSiteHeader"
              Name="WebSiteHeader"
              Root="HKLM"
              Key="SOFTWARE\torresdal.net\SimpleWebApp\Install"
              Type="raw" />
    </Property>
    <CustomAction Id="GetIISWebSites" BinaryKey="IISCA" DllEntry="GetWebSites" Execute="immediate"  Return="check" />
    <Binary Id="IISCA" SourceFile="$(var.SolutionDir)IISCustomAction\bin\Debug\IISCustomAction.CA.dll" />
    <InstallUISequence>
      <Custom Action="GetIISWebSites" After="CostFinalize" Overridable="yes">NOT Installed</Custom>
    </InstallUISequence>
    <Directory Id="TARGETDIR" Name="SourceDir">
      <Directory Id="ProgramFilesFolder">
        <Directory Id="INSTALLLOCATION" Name="SimpleWebApp">
          <Component Id="Default.aspx" Guid="fc46b1a2-35e9-4a17-896b-80b2daaae567">
            <File Id="Default.aspx" Name="Default.aspx" Source="$(var.SolutionDir)SimpleWebApp\Default.aspx" DiskId="1" KeyPath="yes" />
          </Component>
          <Component Id="Web.config" Guid="2ED81B77-F153-4003-9006-4770D789D4B6">
            <File Id="Web.config" Name="Web.config" Source="$(var.SolutionDir)SimpleWebApp\Web.config" DiskId="1" KeyPath="yes" />
            <util:XmlFile Id="AppSettingsAddNode" File="[INSTALLLOCATION]Web.config" Action="createElement" ElementPath="/configuration/appSettings" Name="add" Sequence="1" />
            <util:XmlFile Id="AppSettingsKeyAttribute" Action="setValue" File="[INSTALLLOCATION]Web.config" ElementPath="/configuration/appSettings/add" Name="key" Value="AddedDuringInstall" Sequence="2" />
            <util:XmlFile Id="AppSettingsValueAttribute" Action="setValue" File="[INSTALLLOCATION]Web.config" ElementPath="/configuration/appSettings/add" Name="value" Value="This text was added during installation." Sequence="3" />
          </Component>
          <Directory Id="binFolder" Name="bin">
            <Component Id="SimpleWebApp.dll" Guid="7FC6DA37-12E5-463d-8E7E-08F73E40CCF2">
              <File Id="SimpleWebApp.dll" Name="SimpleWebApp.dll" Source="$(var.SolutionDir)SimpleWebApp\Bin\SimpleWebApp.dll" DiskId="1" KeyPath="yes" />
            </Component>
          </Directory>
        </Directory>
      </Directory>
      <Directory Id="ProgramMenuFolder">
        <Directory Id="MyWebAppStartMenuFolder" Name="SimpleWebApp">
          <Component Id="StartMenuFolder" Guid="B3AEC4C4-3F8E-4865-B87A-B750533776B5" >
            <util:InternetShortcut Id="SimpleWebAppShortcut" Name="SimpleWebApp" Target="http://localhost/SimpleWebApp/Default.aspx" Directory="MyWebAppStartMenuFolder" />
            <RemoveFolder Id="RemoveStartMenuFolder1" On="uninstall"/>
            <RegistryKey Root="HKCU" Key="SOFTWARE\torresdal.net\SimpleWebApp\SimpleWebAppShortcut">
              <RegistryValue Type="string" Value="Default Value"/>
            </RegistryKey>
          </Component>
        </Directory>
      </Directory>
      <Component Id="IISApplication" Guid="FFA12D9C-5AEC-45f8-AA7D-5C4CEC7FA466">
        <iis:WebAppPool Id="SWAAppPool" Name="SWAAppPool" />
        <iis:WebVirtualDir Id="VirtualDir" Alias="[TARGETVDIR]" Directory="INSTALLLOCATION" WebSite="SelectedWebSite">
          <iis:WebApplication Id="SimpleWebAppApp" Name="[TARGETVDIR]" WebAppPool="SWAAppPool" />
          <iis:WebDirProperties Id="WebVirtualDirProperties" Execute="yes" Script="yes" Read="yes" WindowsAuthentication="no" AnonymousAccess="yes" IIsControlledPassword="yes" />
        </iis:WebVirtualDir>
      </Component>
      <Component Id="PersistWebSiteValues" Guid="C3DAE2E2-FB49-48ba-ACB0-B2B5B726AE65">
        <RegistryKey Root="HKLM" Key="SOFTWARE\torresdal.net\SimpleWebApp\Install">
          <RegistryValue Name="WebSiteDescription" Type="string" Value="[WEBSITE_DESCRIPTION]"/>
          <RegistryValue Name="WebSitePort" Type="string" Value="[WEBSITE_PORT]"/>
          <RegistryValue Name="WebSiteIP" Type="string" Value="[WEBSITE_IP]"/>
          <RegistryValue Name="WebSiteHeader" Type="string" Value="[WEBSITE_HEADER]"/>
        </RegistryKey>
      </Component>
    </Directory>
    <CustomTable Id="AvailableWebSites" >
      <Column Id="WebSiteNo" Category="Identifier" PrimaryKey="yes" Type="int" Width="4" />
      <Column Id="WebSiteDescription" Category="Text" Type="string" PrimaryKey="no"/>
      <Column Id="WebSitePort" Category="Text" Type="string" PrimaryKey="no"/>
      <Column Id="WebSiteIP" Category="Text" Type="string" PrimaryKey="no" Nullable="yes"/>
      <Column Id="WebSiteHeader" Category="Text" Type="string" PrimaryKey="no" Nullable="yes"/>
      <Row>
        <Data Column="WebSiteNo">0</Data>
        <Data Column="WebSiteDescription">Bogus</Data>
        <Data Column="WebSitePort">0</Data>
        <Data Column="WebSiteIP"></Data>
        <Data Column="WebSiteHeader"></Data>
      </Row>
    </CustomTable>
    <iis:WebSite Id="SelectedWebSite" Description="[WEBSITE_DESCRIPTION]">
      <iis:WebAddress Id="AllUnassigned" Port="[WEBSITE_PORT]" IP="[WEBSITE_IP]" Header="[WEBSITE_HEADER]" />
    </iis:WebSite>
    <Property Id="WIXUI_INSTALLDIR" Value="INSTALLLOCATION" />
    <UIRef Id="MyUI" />
    <Feature Id="ProductFeature" Title="SimpleWebApp" Level="1">
      <ComponentRef Id="Default.aspx" />
      <ComponentRef Id="Web.config" />
      <ComponentRef Id="SimpleWebApp.dll" />
      <ComponentRef Id="StartMenuFolder" />
      <ComponentRef Id="IISApplication" />
      <ComponentRef Id="PersistWebSiteValues" />
    </Feature>
  </Product>
</Wix>

The End! 
That’s that! If you’ve come this far you (hopefully) have a functional CA with goodies that allow your user to select web sites in your installer. Hope you found this post useful and let me know if you find any errors or questions, and I’ll help you out. Btw here’s the end result:

As mentioned before, I created a small tool for sending out emails to our members in NNUG. When implementing tools like these I always make sure to experiment with new language features, patterns or similar. This time it was the fluent interface to be tested.

Recently there has been a lot of focus on Domain Specific Languages (DSL's). A Fluent Interface is a specific type of DSL. Martin Fowler and Eric Evans gave this DSL type its name in 2005 which you can read more about here.

To jump right into the usage of my interface here's how to send an email to one person from code:

EmailComponent email = Email
    .To("somebody@torresdal.net")
    .From("anybody@torresdal.net")
    .WithSubject("Anybody out there?")
    .Using.Body("Guess not...");
email.Send();

The above code is nice, but you can't really do anything useful with it. You can send emails from code, but I would rather use an email client for that So lets make it a bit more interesting:

EmailComponent email = Email
    .ToAllIn("recipients.txt")
    .From("anybody@torresdal.net")
    .WithSubject("Anybody out there?")
    .Using.TxtBodyFromFile("someTxtFile.txt")
    .Using.HtmlBodyFromFile("someHtmlFile.html");
email.Send();

Now instead of specifying one single to address we point to a file where all the recipients are found. Also instead of the body text we use a text file and a html file to be used as the email body. In this way, when you send emails, people that can only receive plain text emails will get that, and the others will get the html version. This is done using the AlternateView class in .Net.

But there is more interesting stuff you can do:

EmailComponent email = Email
    .ToAllIn("recipients.txt")
    .From("anybody@torresdal.net")
    .WithSubject("Anybody out there?")
    .Using.TxtBodyFromFile("someTxtFile.txt")
    .Using.HtmlBodyFromFile("someHtmlFile.html")
    .PauseAfter.Every(30).EmailSent.For(20).Minutes;
email.Send();

In the last line we say: Pause after every 30 email sent for 20 minutes. So what would you use that for? If you send out 500 emails, your smtp server might not like you very much, so he/she just reject your request thinking you're a spammer. By splitting it up you still might be a spammer, but the smtp server won't know it.

There are many variants of the above line. Here's a few other examples:

.PauseAfter.Every(10).Minutes.For(1).Hour;

.PauseAfter.Every().Hour.For(2).Hours

How is this done you might ask? First of I read Anders Norås excellent article about fluent interfaces (Behind the scenes of the planning DSL) and Martin Fowler's articles from his coming book about DSL's to get a deeper understanding.

So in essence I've basically picked the right words (hopefully) for the method names and properties to build up an understandable sentence implemented by using Method Chaining. Here's what Martin Fowler says about method chaining:

Method Chaining is an idiom that acheives this through a sequence of modifier calls where each call returns the host object for further modification.

Implementing method chaining is quite simple illustrated by the code below:

public Email To(string emailAddress)
{
    _to = emailAddress;
    return this;
}

This is from my Email class of the fluent interface. See how it returns itself? This is so that you can do subsequent calls to the same class.

If you've been very observant you've seen that the To method returns an Email object, but the object type returned after the "sentence" is finished is an EmailComponent. As Anders accurately describe in his post this is done using an implicit user-defined type conversion operator in C#. It's actually not as difficult as it might sound Check out Anders article for details.

Another good point made by Anders is writing this without "code by example" or TDD is almost impossible. Write your sentences first and then implement the code. Actually, for people trying to learn/master TDD an excellent way of practicing is writing a fluent interface!

Even though this was really cool (at least I think so), is it any useful? If you see where fluent interfaces are used today, they tend to be around configuration. Instead of hacking around in an xml file not really knowing when you miss type something, using a type safe fluent interface might be a good idea. Examples of this is Ninject, NHibernate and others. Is my Email client any good as a fluent interface? If you remove the PauseAfter functionality the answer is: not really. However, the PauseAfter thing actually adds some value to it all. There are other ways of solving that quite nice just using a plain API, but that's no fun is it?!

It's great when we manage to get people like Dan North to NNUG. Many knew who he was from before and where excited to hear what he had to say, others didn't know so much about him but where excited by what the others told them. Dan talked about BDD and DDD, and how they are related. He said that without DDD, BDD would not have existed (hope I got that right). Which says a lot about BDD AND DDD!

One of the more funny things I remember from the event (which is not related to the topic itself) was the use of I in Interface in e.g. C#. So Dan said, why not use the I for something meaningful? Ask the interface the question: What do you do? And the interface says: ISendEmail or ISearchFiles or IPingComputers. This is a great way of giving interfaces roles. I just think this is brilliant!

My overall impression of the event was really good, but I would like to know what you think. Comment on this blog or drop me an email here. Actually since we had him over at Contiki as well, I'm a bit confused about what was said in his presentation and not Right now there is so much new and interesting knowledge trying to be consumed in my brain that I'm having problems concentrating  

I hope you liked the event and I also hope you would like us to continue getting people like Dan to Bergen.

If you are like me you probably have a hard time finding something to create when trying out new stuff.  This time I sat down and tried to figure out something to use LINQ and Silverlight for and maybe WCF, WPF and Ajax as well. At the time I was watching TV and the EPG (Electronic Programming Guide) didn’t work, so I started to look for a web site with a program guide supporting reminders and other nice features to let you know what’s on TV. I didn’t find anything good.
I then started to look for an xml/text format for TV programs. I did some searching and came across xmltv. Nice! I now had an xml source looking something like this:

<tv>
  <channel id="channel1">    
    <display-name lang="nb">Channel 1</display-name>
  </channel>
  <channel id="channel2">
    <display-name lang="en">Channel 2</display-name>
  </channel>
  ...
  <programme start="20070801033000 +0200" stop="20070801053000 +0200" channel="channel1">
    <title lang="nb">Program 1</title>
    <desc lang="nb">Program description.</desc>
    <credits>
      <director>...</director>
      <actor>...</actor>
      <actor>...</actor>
    </credits>
    <date>2004</date>
    <category lang="en">movie</category>
    <category lang="en">drama</category>
  </programme>
  ...
</tv>

So now I had an xml document containing all the data I needed and this was a perfect time to try out XLINQ. I decided to stick with the LINQ query syntax and not mix in Lambda expressions to keep things simple and readable. I came up with this expression to get all TV channels:

public List<TvChannel> GetTvChannelsWithoutGuide()
{
    IEnumerable<TvChannel> channels;
    try
    {
        XElement tvGuide = XElement.Load(_xmlFileLoc);

	channels = from c in tvGuide.Descendants("channel")
		   orderby (string)c.Element("display-name") 
                     ascending
		   select new TvChannel
		   {
		       Id = (string)c.Attribute("id"),
		       Name = (string)c.Element("display-name"),
		       Lang = (string)c.Element("display-name")
                                .Attribute("lang"),
		       TvGuideLoaded = false
		   };
    }
    catch (FileNotFoundException fileNotFoundEx)
    {
        throw new FileNotFoundException(
                  string.Format("Xml file for tv guide not found at {0}",
		_xmlFileLoc), fileNotFoundEx);
    }
    return channels.ToList<TvChannel>();
}

The XElement gives me the complete xml document that I can use XLINQ expressions on. In my query I’m looking only for TV channels, so I specify that in the query by

    from c in tvGuide.Descendants("channel")

This gives my a variable c that I use in my orderby clause and select statement. The orderby clause

    orderby (string)c.Element("display-name") ascending

uses the c variable to access the “display-name” element to set order by. But it’s the select statement which is the cool thing here! First here a listing of the TvChannel class:

[Serializable]
public class TvChannel
{
    public string Id { get; set; }
    public string Name { get; set; }
    public string Lang { get; set; }

    [XmlIgnore]
    public IEnumerable<TvProgramme> TvGuideNonSerializable {
        get { return TvGuide; }
        set { TvGuide = value.ToList(); } 
    }

    public List<TvProgramme> TvGuide
    {
        get;
        set;
    }
    public bool TvGuideLoaded { get; set; }
} 

Ignore the TvGuideNonSerializable property for now. By using select new TvChannel I can create an object of my TvChannel class an assign data from the xml document to my properties. I just love this syntax! It’s really nice and easally understandable. Another cool feature (running VS 2008 Beta 2) is that you get ItelliSense in LINQ for your classes, like this:



I also created other methods for retrieving all programs for one channel, all channels etc. At the time of writing I’m working on a Silverlight implementation for the TvGuide which I hopefully can show you soon. And later I’ll make all source code available.

Ever been annoyed by not being able to find the real object behind System.__ComObject? There is a solution and guess what; it's VB.Net (or at least the VB API)! Carlos has a how-to article that explains the solution. In essence you just have to have a reference (if you're running C# or a non VB language) to Microsoft.VisualBasic.dll. You can then use Microsoft.VisualBasic.Information.TypeName(someObject) to get the info you want. Thanks to Pablo Galiano for his blog post on this.

You've probably all seen this already, since you read Scott Guthrie’s blog as well (or that you’ve been on the internet after 2005), but he just posted a few examples of some of the new features in the C# Orcas framework. I can't wait to start using the automatic properties! I don’t know how many hours I’ve spent writing stupid get/set properties that only do one thing, return a private field.

You might argue that it was about time some of these features got implemented or that they (MS) are just stealing from other languages. To be honest I don’t care as long as the language gets better and more productive to use.

If you want to see the “complete” spec for C# features, you can check out this document: http://download.microsoft.com/download/5/8/6/5868081c-68aa-40de-9a45-a3803d8134b8/csharp_3.0_specification.doc