Part 1 - Simple configuration

Welcome to part 1... today we're looking at supporting basic configuration in components without additional coding by using the windsor container.

So - with the container we can provide configuration for a component which is loaded at runtime, so every time you start your app it will be read in - you can do this using the configuration support in .Net - but using castle makes support for this very code-light in comparison... let's take a look.

So first off, we have a class we can use to calculate the tax on a gross ammount:

public class TaxCalculator
private decimal _rate = 0.125m;

public decimal Rate
set { _rate = value; }
get { return _rate; }

public decimal CalculateTax(decimal gross)
return Math.Round(_rate*gross, 2);

By default the tax rate is 12.5% - but we can change the tax rate by setting the "Rate" property.

Now, lets look at setting up the container... so we have this code in our sample:

private static void Main(string[] args)
WindsorContainer container = new WindsorContainer(new XmlInterpreter());

TaxCalculator calculator = container.Resolve();

decimal gross = 100;
decimal tax = calculator.CalculateTax(gross);

Console.WriteLine("Gross: {0}, Tax: {1}", gross, tax);

The windsor container is constructed with an "XmlInterpreter" - this configuration will pull the setup for our container from a section in the App.config.

Let's have a look at that:

type="Castle.Windsor.Configuration.AppDomain.CastleSectionHandler, Castle.Windsor" />

Running the program will display: Gross: 100, Tax: 12.50

Now, what about changing the tax rate in the configuration?

type="Castle.Windsor.Configuration.AppDomain.CastleSectionHandler, Castle.Windsor" />


Now running the program will display: Gross: 100, Tax: 25.00

And that's part 1 done - so now you can see how can we supply configuration parameters, and provide sensible defaults for them.

Next time we'll look at configuring arrays...

Written on April 17, 2007