Hi Fixer,

From your description, you're creating a custom ConfigurationSection and
use it in ASP.NET application, however, you encountered " object can not be
cast to ..." error at runtime when try referecing to the custom section
object, correct?

Regarding on this issue, I've performed some tests on my side, seems a very
simple and typical custom configurationSection can work correctly in
ASP.NET application. I think the problem is likely be specific to the
project or environment. I would suggest you also try creating a very simple
custom configurationSection and use it in a new created ASP.NET web site
project(or you can also try move the custom section into a separate class
library project).  

In addition, I'm wondering how to configure the section in web.config and
reference it in code. Here is my test code(include custom section class,
web.config section and referencing code):

#the custom section class is put in the App_Code folder of the ASP.NET
application
===========custom section code=================
public class MySection: ConfigurationSection
{
   public MySection()
   {
     
   }

   [ConfigurationProperty("key", IsKey = true)]
   public string Key
   {
       get
       {
           return ((string)(base["key"]));
       }
       set
       {
           base["key"] = value;
       }
   }

   [ConfigurationProperty("value")]
   public string Value
   {
       get
       {
           return ((string)(base["value"]));
       }
       set
       {
           base["value"] = value;
       }
   }

}

=========web.config=============
 <configSections>
   <section name="MySection" type="MySection, __code" />
 </configSections>

.....................

========code in page=========

ConfigurationSection section =
WebConfigurationManager.GetSection("MySection") as ConfigurationSection;
       if (section != null)
           Response.Write("<br/>mysection: " + ((MySection)section).Key +
"|" + ((MySection)section).Value);
============================

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead

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