Question

I have created a config file within my project, and called it MyConfig.config. It contains the following:

<configuration>
  <MySection MyString="StringHere"/>
</configuration>

I’’m trying to access this as follows:

AppSettingsSection settings = (AppSettingsSection)ConfigurationManager.GetSection("MySection");
string myString = settings.Settings["MyString"].Value;

Clearly I’m doing something wrong. Is it even possible to use the ConfigurationManager in this way?

Answer 1

Yes, it is possible. There are a couple of steps. First, you have to define your section in the config. This involves declaring the section name and the type (class you have written):

<configSections>
   <sectionGroup name="system.web">
      <section name="myConfig" type="MyConfig.MyConfigSectionHandler,MyConfig" />
   </sectionGroup>
</configSections>

Next, you have to actually write the code to handle the section. It must inherit from IConfigurationSectionHandler:

using System;
using System.Web;
using System.Xml;
using System.Configuration;

namespace MyConfig
{
   public enum LevelSetting
   {
      High,
      Medium,
      Low,
      None
   }
   public class MyConfigSectionHandler : IConfigurationSectionHandler
   {
      public virtual object Create(object parent,object configContext,XmlNode section)
      {
         int iLevel = 0;
         string sName = "";

         ConfigHelper.GetEnumValue(section, "level", typeof(LevelSetting), ref iLevel);
         ConfigHelper.GetStringValue(section,"name",ref sName);
         return new MyConfigSection((LevelSetting)iLevel,sName);
      }
   }
   public class MyConfigSection
   {
      private LevelSetting level = LevelSetting.None;
      private string name = null;

      public MyConfigSection(LevelSetting _level,string _name)
      {
         level = _level;
         name = _name;
      }
      public LevelSetting Level
      {
         get {return level;}
      }
      public string Name
      {
         get {return name;}
      }
   }
   internal class ConfigHelper
   {
      public static XmlNode GetEnumValue
      (XmlNode _node, string _attribute,Type _enumType, ref int _val)
      {
         XmlNode a = _node.Attributes.RemoveNamedItem(_attribute);
         if(a==null)
            throw new ConfigurationException("Attribute required: " + _attribute);
         if(Enum.IsDefined(_enumType, a.Value))
            _val = (int)Enum.Parse(_enumType,a.Value);
         else
            throw new ConfigurationException("Invalid Level",a);
         return a;
      }
      public static XmlNode GetStringValue(XmlNode _node, string _attribute, ref string _val)
      {
         XmlNode a = _node.Attributes.RemoveNamedItem(_attribute);
         if(a==null)
            throw new ConfigurationException("Attribute required: " + _attribute);
         else
            _val = a.Value;
         return a;      
      }
   }
}

Next, add the actual configuration item into the web.config:

<system.web>
    <myConfig level="High" name="hello world" />
</system.web>

Done.