Creating Custom Configuration Sections
Introduction
ASP.NET allows you to store your own configuration settings in the <appSettings>
section of web.config file. This section allows you to store settings as
key-value pairs. This works well if you have few key-value pairs. However, if
you have many such configuration settings then it becomes bit difficult to
categorically store the values. Good part is that ASP.NET allows you to define
your own sections to store such settings. In this article we will see how to
create your own configuration sections and access them in your code.
Section Handlers
The web.config file consists of several sections and each such section is
supposed to be processed by a section handler. A section handler is nothing but
a class that implements IConfigurationSectionHandler interface. In this article
we will not go into the details of this interface but we will see how to use one
built-in section handler. You can specify the section handler for a particular
section in the web.config file itself.
Specifying Section Handler
Let's assume that you want to create a custom configuration section like
this:
<sitesettings>
<common>
<emails>
<add key="adminmail" value="administrator@somedomain.com"/>
<add key="salesmail" value="sales@somedomain.com"/>
<add key="supportmail" value="support@somedomain.com"/>
<add key="admail" value="advertising@somedomain.com"/>
</emails>
</common>
</sitesettings>
Here, we are storing the configuration settings as key-value pairs but they
are nested inside other tags.
Now that you know how your section is going to be, let us put markup in
web.config that will indicate how this section will be handled. .NET comes with
a built-in section handler called NameValueSectionHandler that resides in
System.Configuration namespace. This handler is responsible to handle sections
that store settings as key-value pairs (such as <appSettings>). We will be
using this section handler for our section.
<configuration>
<configSections>
<sectionGroup name="sitesettings">
<sectionGroup name="common">
<section name="emails" type=
"System.Configuration.NameValueSectionHandler,System"/>
</sectionGroup>
</sectionGroup>
</configSections>
...
...
...
Reading section values in your code
Once you put section handler and sections in your web.config you can access
the values in your code as follows:
NameValueCollection nvc = (NameValueCollection)
ConfigurationSettings.GetConfig("sitesettings/common/emails");
Label1.Text = nvc["salesmail"];
Label2.Text = nvc["supportmail"];
Label3.Text = nvc["adminmail"];
...
...
Summary
In this article we saw how to create your custom web.config sections.
Web.config sections are handled by classes implementing
IConfigurationSectionHandler interface. We used NameValueSectionHandler class
that handles <appSettings> section of web.config. In the next article we will
see how to create our own class that implements IConfigurationSectionHandler and
process our custom sections.
