ASP.NET Cookbook

9.5. Accessing Other web.config Configuration Elements

Problem

You want to be able to read application information from a web.config file that is not available as an <appSettings> key/value pair, but present as an attribute or child element of some other element of the file.

Solution

Read the web.config file into an XmlDocument object, and access the target element that contains the information you need as you would any other XML document node.

In the code-behind class for your ASP.NET page, use the .NET language of your choice to:

1. Read the web.config file into an XmlDocument object.

2. Use the SelectSingleNode method to get a reference to the desired section.

3. Use the attributes collection of the selected node to access the attributes for the section.

Example 9-6 through Example 9-8 show an application we’ve written that implements this solution and retrieves attribute settings from the <trace> element of a web.config file. Example 9-6 shows the .aspx file that displays the information. Example 9-7 (VB) and Example 9-8 (C#) show the code-behind class for the page that does the work of reading the settings from the <trace> element.

Discussion

Because the web.config file is an XML document, you can process it as you would any other XML document and use the XML classes provided in the .NET Framework to access its elements and their children. The first step is to create a new XmlDocument object and load the web.config file into it. In our example, we use Server.MapPath to get the fully qualified ...