Reading web.configuration values in asp.net application

In my asp.net application I want to read authorization 开发者_开发技巧section of web.config and modify that. For that I am using the below code but I am not getting the values. So have a look at it and let me know if there is any way to read and update authorization section values AuthorizationSection section; my section is like the following

 <authorization>
       <deny users="?"/>
 </authorization>

And this is the code:

configuration = WebConfigurationManager.OpenWebConfiguration("~");
section = (AuthorizationSection)configuration.GetSection("system.web/authorization"); 
SectionInformation sc= section.SectionInformation;

Thanks, Hima.

Try this:

AuthorizationSection section = (AuthorizationSection)ConfigurationManager
                                   .GetSection("system.web/authorization");

Add reference to System.Configuration.dll

Update:

Try this:

    AuthorizationSection section = (AuthorizationSection)ConfigurationManager
                               .GetSection("system.web/authorization");
    foreach (AuthorizationRule rule in section.Rules)
    {
        //rule.Users <- StringCollection
        //rule.Action;
    }