Are you tired of seeing your configuration settings as an endless list of key value pairs?
<add key="key0" value="value0" />
<add key="key1" value="value1" />
<add key="key2" value="value2" />
...
Would you rather see something more like this?
<MySetting
fileName="c:\temp"
password="pencil"
someOtherSetting="value" />
Join the club. Not only is the first approach prone to typos (AppSettings["tire"] or AppSettings["tier] anyone?), too many of these things all bunched together can cause your eyes to glaze over. It is a lot easier to manage when settings are grouped in logical bunches.
A while back Craig Andera solved this problem with the Last Configuration Section Handler he’d ever need. This basically made it easy to specify a custom strongly typed class to represent a logical group of settings using Xml Serialization. It led to a much cleaner configuration file.
But that was then and this is now. With ASP.NET 2.0, there’s an even easier way which I didn’t know about until Jeff Atwood recently turned me on to it.
So here is a quick run through in three easy steps.
Step one - Define your Custom Configuration Class
In this case, we’ll define a class to hold settings for a blog engine. We just need to define our class, inherit from System.Configuration.ConfigurationSection, and add a property per setting we wish to store.
using System;
using System.Configuration;
public class BlogSettings : ConfigurationSection
{
private static BlogSettings settings
= ConfigurationManager.GetSection("BlogSettings") as BlogSettings;
public static BlogSettings Settings
{
get
{
return settings;
}
}
[ConfigurationProperty("frontPagePostCount"
, DefaultValue = 20
, IsRequired = false)]
[IntegerValidator(MinValue = 1
, MaxValue = 100)]
public int FrontPagePostCount
{
get { return (int)this["frontPagePostCount"]; }
set { this["frontPagePostCount"] = value; }
}
[ConfigurationProperty("title"
, IsRequired=true)]
[StringValidator(InvalidCharacters = " ~!@#$%^&*()[]{}/;’\"|\\"
, MinLength=1
, MaxLength=256)]
public string Title
{
get { return (string)this["title"]; }
set { this["title"] = value; }
}
}
Notice that you use an indexed property to store and retrieve each property value.
I also added a static property named Settings for convenience.
Step 2 - Add your new configuration section to web.config (or app.config).
<configuration>
<configSections>
<section name="BlogSettings" type="Fully.Qualified.TypeName.BlogSettings,
AssemblyName" />
</configSections>
<BlogSettings
frontPagePostCount="10"
title="You’ve Been Haacked" />
</configuration>
Step 3 - Enjoy your new custom configuration section
string title = BlogSettings.Settings.Title;
Response.Write(title); //it works!!!
What I covered is just a very brief overview to get you a taste of what is available in the Configuration API. I wrote more about configuration in the book I’m cowriting with Jeff Atwood, Jon Galloway, and K. Scott Allen.
If you want to get a more comprehensive overview and the nitty gritty, I recommend reading Unraveling the Mysteries of .NET 2.0 Configuration by Jon Rista.
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