.NET Tip: Create a Custom Configuration Section in .NET 2.0

The configuration file concept in .NET makes it much easier to change runtime settings without having to recompile. These files hearken back to the days of .INI files in previous versions of Windows, long before the dreaded Registry. Although you can keep all your settings in the appSettings section, you also can add your own custom configuration sections to make your settings a bit more orderly and easy to find within a configuration file. This tip shows you how to build a custom configuration section to hold settings dealing with sending e-mail.

The Configuration Class

The first thing you need is a configuration class that derives from the System.Configuration.ConfigurationSection class. This class will have a property for each configuration property you want to set. Here's the class I created:

public class MailManagerConfiguration : ConfigurationSection
{
   public MailManagerConfiguration()
   {
   }

   [ConfigurationProperty("serverAddress",
                          DefaultValue = "mail.northcomp.com",
                          IsRequired = true)]
   public String MailServer
   {
      get
      { return (String)this["serverAddress"]; }
      set
      { this["serverAddress"] = value; }
   }

   [ConfigurationProperty("messageTemplate", IsRequired = true)]
   public String MessageTemplate
   {
      get
      { return (String)this["messageTemplate"]; }
      set
      { this["messageTemplate"] = value; }
   }

   [ConfigurationProperty("baseURL", IsRequired = true)]
   public String BaseURL
   {
      get
      { return (String)this["baseURL"]; }
      set
      { this["baseURL"] = value; }
   }

   [ConfigurationProperty("from",
   DefaultValue = "Eric Smith <eric@northcomp.com>",
      IsRequired = true)]
   public String ReturnAddress
   {
      get
      { return (String)this["from"]; }
      set
      { this["from"] = value; }
   }

   [ConfigurationProperty("title", DefaultValue =
                          "Announcement from Eric :: {0}",
                          IsRequired = true)]
   public String TitleFormat
   {
      get
      { return (String)this["title"]; }
      set
      { this["title"] = value; }
   }
}

This class has the following five properties:

  • One for the address of the mail server
  • One for the template for the message
  • A base URL for all the links and images
  • A return address
  • A title format for the message subject

From this example, you can see how these properties can be required or optional and can have a default value in case one is not specified in the configuration file.

The configuration file needs the following code to use this configuration section:

<configuration>
   <configSections>
      <section name="MailManagerConfiguration"
               type="MyLibrary.MailManagerConfiguration,
                     MyLibrary" />
   </configSections>
   <MailManagerConfiguration
      serverAddress="mail.myserver.com"
      messageTemplate="C:\Web\mailmanager\template.html"
      baseURL="http://www.northcomp.com"
      from="Northstar Computer Systems
         &lt;clientcenter@northcomp.com&gt;"
      title="My Web Site:: {0}" />

The type parameter in the section tag first references the full name of the class (including any namespace), followed by the class name by itself. I generally keep these classes in a separate library for just this reason.

Each of the parameters in the configuration class has a corresponding value in the MailManagerConfiguration tag, as you can see above. The purpose of each value is specific to what the class needs, but you can see how to lay things out in the configuration file.

Instantiate the Configuration Class

The last step is instantiating the configuration class and using the properties, as shown here:

MailManagerConfiguration config =
   (MailManagerConfiguration)ConfigurationManager.GetSection
   ("MailManagerConfiguration");

Once you have this class instantiated, you can read any of the properties, such as config.ReturnAddress, config.TitleFormat, and so on.

By creating this custom configuration section, you've made your class more modular and not reliant on the generic appSettings section in the configuration file. Users who work with the class will know what the settings are for and be able to access them more easily in their code.

About the Author

Eric Smith is the owner of Northstar Computer Systems, a Web-hosting company based in Indianapolis, Indiana. He is also a MCT and MCSD who has been developing with .NET since 2001. In addition, he has written or contributed to 12 books covering .NET, ASP, and Visual Basic.



Comments

  • Using Collections inside the section

    Posted by Magallo on 04/11/2007 11:18am

    I saw in your example that your MailManagerConfiguration class contains only String properties. Is there the possibility to use a Collection or a List or an array of "something" as a property of my ConfigurationSection derived class? I mean, in my section data I have a list of "somedata" and I would like to have a property inside my class that is a sort of List or something like that. Can you make an exapmple? Thanks.

    Reply
Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • On-demand Event Event Date: September 10, 2014 Modern mobile applications connect systems-of-engagement (mobile apps) with systems-of-record (traditional IT) to deliver new and innovative business value. But the lifecycle for development of mobile apps is also new and different. Emerging trends in mobile development call for faster delivery of incremental features, coupled with feedback from the users of the app "in the wild." This loop of continuous delivery and continuous feedback is how the best mobile …

  • As mobile devices have pushed their way into the enterprise, they have brought cloud apps along with them. This app explosion means account passwords are multiplying, which exposes corporate data and leads to help desk calls from frustrated users. This paper will discover how IT can improve user productivity, gain visibility and control over SaaS and mobile apps, and stop password sprawl. Download this white paper to learn: How you can leverage your existing AD to manage app access. Key capabilities to …

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds