In ASP.NET 2.0, you can manage configuration file from IIS itself i.e. the configuration management API is integrated with IIS itself. This feature is available as Microsoft Management Console (MMC), which can be accessed from the properties settings of any website in. Using this console, administrator can modify both machine.config file and web.config file.

A new ASP.NET tab is included in the IIS site properties window, which is shown below.

Note: Edit machine.config button will be there only when you select properties section of a website. This wont be there when you select properties section for a virtual directory in IIS

In this tab, you can specify the version of asp.net for that web application. In previous release, if you want to change the aspnet.version for a web application, you need to use command line utility aspnet_regiis, which comes with .NET Framework. Now you can do this from IIS itself. If you want to edit machine.config, you can press Edit machine.config file button. Similarly, if you want to edit web.config file, you can press edit configuration. Both this button will invoke a separate window, which has option for editing various sections in config file. This window is show below

The configuration settings shown in this window are merged view of settings from all the levels of hierarchy i.e. from machine.config to web.config in the root folder of that application.

Using configuration API’s

Another method to edit configuration file in ASP.NET is using Configuration API’s. .NET Framework 2.0 provides strongly typed API’s for editing and reading configuration files. Both WebSiteAdministration tool and IIS MMC snapin use this API’s internally to update configuration files. Configuration class is present in System.Configuration namespace can be used to access the configuration of any application (webapplication, windows application or console application) in .NET 2.0. The configuration class has following methods,

1. GetWebConfiguration

This method is used to the access the configuration of a web application (web.config). This method retrieves the combined configuration for a web application.

2. GetExeConfiguration

This method is used to access the configuration of any standalone application (app.config)

3. GetMachineConfiguration.

This method is used to access the configuration details for specific computer (machine.config)

In this article, we will concentrate on GetWebconfiguration method only. Other methods also behave in the same way. GetWebconfiguration method accepts relative URL for a web application and returns the configuration data for that website. For example,

Dim cnfg As System.Configuration.Configuration
cnfg = Configuration.GetWebConfiguration(Request.ApplicationPath)
Dim str As String
Dim conn As String
str = cnfg.AppSettings.Settings.Item("TempDir")
conn= cnfg.ConnectionStrings.ConnectionStrings.Item(1).ConnectionString
 

GetWebConfiguration method accepts relative URL (applicationpath) and returns configuration. Most of the sections in config file are available as properties in configuration class. In the above example, appsettings configuration values and connectionstring values are retrieved using AppSettings property and ConnectionString property in Configuration class. Similarly, location, section group section in config file can also be directly accessed from Configuration class. Other sections like Trace, Session can be accessed using getSection method. getSection is the generic method available in configuration class to access any settings in config by providing the path of those settings.

Following example shows how to enable trace using Configuration class,   

Dim cnfg As System.Configuration.Configuration
cnfg = System.Configuration.Configuration.GetWebConfiguration(Request.ApplicationPath)
Dim trace As System.Web.Configuration.TraceSection
trace = DirectCast(cnfg.GetSection("system.web/trace"), 
System.Web.Configuration.TraceSection)
trace.Enabled = True
cnfg.Update()