I’m starting work on a new project on Monday and I’ve got full control of all development aspects. With that in mind, I’ve been thinking of how I can get to beta status as quickly as possible - finish main development and get to the stage where the client is reviewing minor details. This is dependant on a combination of my skillset and the tools I’m going to use. I’ve got:

• Existing Plastiscenic.Commons code and project structure for quick setup
• C# 3.0 to remove some boiler plate code (automatic properties for example)
• Monorail to develop with fewer LOC in the main app
• NHibernate for low friction database work
• ExtJS for rich backend
• Strong cross-technology skills to integrate the above

Are there any additions to this that you use to accelerate the development process?

I should file this under “things that are probably a design pattern but I’m not sure exactly what kind”; it seems like one of those typical things that you will naturally stumble upon when using the Repository pattern and indeed when you start to separate out your query logic.

DetachedCriteria is an “offline” version of the NHibernate Criteria class, used to build up Criteria where an NHibernate Session is not available. The NHibernate documentation has more on how to use DetachedCriteria on its own, but I want to talk about inheriting from it to create a simple custom finder class.

Say we have a Active Record Person class, with height and weight properties:

[ActiveRecord]
public class Person : ActiveRecordBase
{
    [PrimaryKey]
    public int Id { get; set; }
    [Property]
    public int Height { get; set; }
    [Property]
    public int Weight { get; set; }
}

The height and weight properties are simplified, and I’m using C# 3.0 automatic properties for clarity. I want to search for a Person based on their height and weight, so to do so, I’ll create a new finder class:

public class PersonFinder : DetachedCriteria
{
    public class PersonFinder(height, weight) : base(typeof(Person))
    {
         Add(Expression.Eq("Height", height));
         Add(Expression.Eq("Weight", weight));
    }
}

A simple class, but it clearly states its purpose. Here’s how it could be used:

Person.FindAll(new PersonFinder(200, 300), new Order("Id", true));

For me, the advantage of this code isn’t just in reducing what you have to type. Instead it is in the readability and discoverability of the code.

I guess this applies to any IoC container, but you get the idea. How would you describe Windsor to a newcomer in just one sentence? I just wrote:

Windsor is a way of passing in different classes to code that is going to use them, it helps you write applications that are very flexible and testable.

But that was pretty off the cuff and I’m not really satisfied with it. Give it a go, it’s pretty hard.

Recently Plastiscenic has been asked to quote for a fairly large project, and if it comes off I’ll have the chance to work on it from the ground up, using whatever technologies I think are best suited.

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I’ve blogged before about the enabling features of Monorail and Active Record, part of the Castle stack. Another piece of software which is making my development life a pleasure is ExtJS - a collection of javascript goodies created by Jack Slocum and his team - and when these three things come together, watch that coding fly…. I’ve created a screencast in which I demonstrate how easy it is to build a paging, sorting, filtering, AJAX-powered grid using ExtJS and Castle, and you can watch it here. It’s 20 minutes long but filled with goodness - and a couple of hacks (forgive me :). Don’t forget to check out all my past screencasts too.

UPDATE: As requested in the comments, you can MonorailExt1 VS Project directory of this.

Ayende quickly posted something called HotSwap, which is a little snippet of code which uses a FileWatcher, Windsor, and on-the-fly code recompilation to increase your productivity. With ASP.NET, building your code changes causes an appdomain restart, and you will typically have to wait a few seconds for the appdomain to come back up before the browser will display your changes. This basically means that when working with ASP.NET, there are no quick code changes - you always have that four second wait till you see the effects.

HotSwap resolves this by building your code for you when it detects a change. Using Windsor it can swap out the old assembly containing your code and replace it with a new dynamically created assembly containing your new code - all automatically. The key advantage of this is that it’s all done in-memory, and none of the DLL files in the bin directory change. This means that you won’t trigger an appdomain restart and your changes can be seen almost instantly!

I was really impressed and excited by this approach so I did a very quick screencast on the topic. I was using the Castle RC3 MSI, and created a project with Windsor integration enabled. This code only works for your controllers at the moment, but a lot of the time that’ll be where you need this kind of productivity boost.

Ayende - cheers for this, and I’m sorry if I pronounced your name wrong as I’ve only seen it written down!

UPDATE: I’ve uploaded the HotswapTest Project from the screencast. You’ll probably need the Castle RC3 MSI installed to build it.

Hammett reports that Castle RC3 is now available. There are loads and loads of changes in this, new Controller test stuff, JSON support, new validation on the server and client - it’s a great release. Get Castle RC3 now.

I’ve been interested in using the Repository pattern in an application for a while now; same goes for Windsor. When prototyping with repositories it became clear that I could use them together in a fairly simple way which would serve as a good introduction to both.

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