Correct implementation of a custom config section

Question

In a web application, I want to be able to define some mapping using a config section like this:

<configuration>
    <configSections>
        <sectionGroup name="MyCustomer">
            <section name="CatalogMappings" type="MyCustom.MyConfigSection" />
        </sectionGroup>
    </configSections>
    <MyCustomer>
        <catalogMappings>
            <catalog name="toto">
                <mapping value="1" displayText="titi" />
                <mapping value="2" displayText="tata" />
            </catalog>
            <catalog name="toto2">
                <mapping value="1" displayText="titi2" />
                <mapping value="2" displayText="tata2" />
            </catalog>
        </catalogMappings>
    </MyCustomer>
</configuration>

I'm struggling to achieve this goal, especially when defining my collection of collections. What are the classes that I need to implement to achieve this?

Currently, I have:

public class CatalogMappingSection : System.Configuration.ConfigurationSection
{
    public class Mapping : ConfigurationElement
    {
        [ConfigurationProperty("externalKey")]
        public string ExternalKey { get; set; }
        [ConfigurationProperty("displayText", IsRequired=true)]
        public string DisplayText { get; set; }
        [ConfigurationProperty("value", IsRequired=true, IsKey=true)]
        public int Value { get; set; }
    }

    public class Catalog : ConfigurationElementCollection
    {
        [ConfigurationProperty("name", IsRequired=true, IsKey=true)]
        public string Name { get; set; }

        protected override ConfigurationElement CreateNewElement()
        {
            return new Mapping();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((Mapping)element).Value;
        }
    }

    public class CatalogCollection : ConfigurationElementCollection
    {
        [ConfigurationProperty("catalog")]
        [ConfigurationCollection(typeof(Catalog))]
        public Catalog CatalogMappingCollection
        {
            get
            {
                return (Catalog)base["catalog"];
            }
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new Catalog();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((Catalog)element).Name;
        }
    }

    [ConfigurationProperty("catalogMappings")]
    [ConfigurationCollection(typeof(CatalogCollection))]
    public CatalogCollection CatalogMappings
    {
        get
        {
            return (CatalogCollection)base["catalogMappings"];
        }
    }
}

But, this is not working as expected.

Answer 1

Due to the popularity of my other answer, I've written a custom example using Usa-States and Usa-Counties. An example that's a tad easier to follow.

I've also added some interfaces, which allows some mocking for unit-tests, something I wasn't fully aware of when I wrote this original answer.

I also added putting the settings in its own file, so your app.config file doesn't have a billion things in it.

I've also added a "Finder" to encapsulate searching for a specific item in the collection.

I've also added a custom Enum.

"UsaStatesSettings.config" (make sure you mark this as "copy-always")

<?xml version="1.0" encoding="utf-8" ?>
<UsaStateDefinitionConfigurationSectionName>
  <usaStateDefinition usaStateFullName="Virginia" usaStateAbbreviation="VA" countyLabelName="County" usaStateDefinitionUniqueIdentifier="111" isContenential="true" >
    <usaCounties>
      <usaCounty usaCountyValue="Bath" />
      <usaCounty usaCountyValue="Bedford" />
      <usaCounty usaCountyValue="Bland" />
    </usaCounties>
  </usaStateDefinition>
  <!-- -->
  <usaStateDefinition usaStateFullName="North Carolina" usaStateAbbreviation="NC" countyLabelName="County" usaStateDefinitionUniqueIdentifier="222" isContenential="true" >
    <usaCounties>
      <usaCounty usaCountyValue="Catawba" />
      <usaCounty usaCountyValue="Chatham" />
      <usaCounty usaCountyValue="Chowan" />
    </usaCounties>
  </usaStateDefinition>
  <!-- -->
  <usaStateDefinition usaStateFullName="Alaska" usaStateAbbreviation="AK" countyLabelName="Borough" usaStateDefinitionUniqueIdentifier="333" isContenential="false" >
    <usaCounties>
      <usaCounty usaCountyValue="Aleutians East" />
    </usaCounties>
  </usaStateDefinition>
  <!-- -->
  <usaStateDefinition usaStateFullName="Lousiania" usaStateAbbreviation="LA" countyLabelName="Parish" usaStateDefinitionUniqueIdentifier="444" isContenential="true" >
    <usaCounties>
      <usaCounty usaCountyValue="Acadia" />
    </usaCounties>
  </usaStateDefinition>
</UsaStateDefinitionConfigurationSectionName>

The "app.config"

<?xml version="1.0" encoding="utf-8" ?>
<configuration>

  <configSections>

    <section name="UsaStateDefinitionConfigurationSectionName" type="GranadaCoder.CustomConfigurationExample.Configuration.UsaStateDefinitionConfigurationSection,GranadaCoder.CustomConfigurationExample.Configuration" />
  </configSections>


  <UsaStateDefinitionConfigurationSectionName configSource="UsaStatesSettings.config" />

  <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
</configuration>

and now the "code"

/**/

// file="CaseInsensitiveEnumConfigurationValueConverter.cs"

using System;
using System.ComponentModel;
using System.Configuration;
using System.Globalization;

namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    public class CaseInsensitiveEnumConfigurationValueConverter<T> : ConfigurationConverterBase
    {
        public override object ConvertFrom(ITypeDescriptorContext ctx, CultureInfo ci, object data)
        {
            return Enum.Parse(typeof(T), (string)data, true);
        }
    }
}


/**/


// file="UsaCountyCollection.cs"


using System.Collections.Generic;
using System.Configuration;

namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    [ConfigurationCollection(typeof(UsaCountyConfigurationElement))]
    public class UsaCountyCollection : ConfigurationElementCollection, IEnumerable<UsaCountyConfigurationElement>
    {
        public override ConfigurationElementCollectionType CollectionType
        {
            get { return ConfigurationElementCollectionType.BasicMap; }
        }

        protected override string ElementName
        {
            get { return "usaCounty"; }
        }

        public UsaCountyConfigurationElement this[int index]
        {
            get { return (UsaCountyConfigurationElement)BaseGet(index); }
        }

        public new UsaCountyConfigurationElement this[string name]
        {
            get
            {
                if (this.IndexOf(name) < 0)
                {
                    return null;
                }

                return (UsaCountyConfigurationElement)BaseGet(name);
            }
        }

        public void Add(UsaCountyConfigurationElement newItem)
        {
            this.BaseAdd(newItem);
        }

        public int IndexOf(string usaCountyValue)
        {
            for (int idx = 0; idx < this.Count; idx++)
            {
                if (this[idx].UsaCountyValue.ToLower(System.Globalization.CultureInfo.CurrentCulture) == usaCountyValue.ToLower(System.Globalization.CultureInfo.CurrentCulture))
                {
                    return idx;
                }
            }

            return -1;
        }

        public new IEnumerator<UsaCountyConfigurationElement> GetEnumerator()
        {
            int count = this.Count;

            for (int i = 0; i < count; i++)
            {
                yield return this.BaseGet(i) as UsaCountyConfigurationElement;
            }
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new UsaCountyConfigurationElement();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((UsaCountyConfigurationElement)element).UsaCountyValue;
        }
    }
}



/**/




// file="UsaCountyConfigurationElement.cs"




using System.ComponentModel;
using System.Configuration;

namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    [System.Diagnostics.DebuggerDisplay("UsaCountyValue='{UsaCountyValue}'")]
    public class UsaCountyConfigurationElement : ConfigurationElement
    {
        private const string UsaCountyValuePropertyName = "usaCountyValue";

        public UsaCountyConfigurationElement()
        {
        }

        public UsaCountyConfigurationElement(string usaCountyValue)
        {
            this.UsaCountyValue = usaCountyValue;
        }

        [ConfigurationProperty(UsaCountyValuePropertyName, IsRequired = true, IsKey = true, DefaultValue = "")]
        [StringValidator(InvalidCharacters = "~!@#$%^&*()[]{}/;’\"|\\")]
        public string UsaCountyValue
        {
            get { return (string)this[UsaCountyValuePropertyName]; }
            set { this[UsaCountyValuePropertyName] = value; }
        }
    }
}


/**/




// file="UsaCountyLabelEnum.cs"




namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    public enum UsaCountyLabelEnum
    {
        Unknown,
        County,
        Parish,
        Borough
    }
}


/**/




// file="UsaStateDefinitionCollection.cs"




using System;
using System.Collections.Generic;
using System.Configuration;

using GranadaCoder.CustomConfigurationExample.Configuration.Interfaces;

namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    [ConfigurationCollection(typeof(UsaStateDefinitionConfigurationElement))]
    public class UsaStateDefinitionCollection : ConfigurationElementCollection, IUsaStateDefinitionCollection
    {
        public UsaStateDefinitionCollection()
        {
            UsaStateDefinitionConfigurationElement details = (UsaStateDefinitionConfigurationElement)this.CreateNewElement();
            if (!string.IsNullOrEmpty(details.UsaStateFullName))
            {
                this.Add(details);
            }
        }

        public override ConfigurationElementCollectionType CollectionType
        {
            get
            {
                return ConfigurationElementCollectionType.BasicMap;
            }
        }

        bool ICollection<UsaStateDefinitionConfigurationElement>.IsReadOnly
        {
            get
            {
                return false;
            }
        }

        protected override string ElementName
        {
            get { return "usaStateDefinition"; }
        }

        public UsaStateDefinitionConfigurationElement this[int index]
        {
            get
            {
                return (UsaStateDefinitionConfigurationElement)BaseGet(index);
            }

            set
            {
                if (this.BaseGet(index) != null)
                {
                    this.BaseRemoveAt(index);
                }

                this.BaseAdd(index, value);
            }
        }

        public new UsaStateDefinitionConfigurationElement this[string name]
        {
            get
            {
                return (UsaStateDefinitionConfigurationElement)this.BaseGet(name);
            }
        }

        public int IndexOf(UsaStateDefinitionConfigurationElement details)
        {
            return this.BaseIndexOf(details);
        }

        public void Add(UsaStateDefinitionConfigurationElement newItem)
        {
            this.BaseAdd(newItem);
        }

        public bool Remove(UsaStateDefinitionConfigurationElement details)
        {
            if (this.BaseIndexOf(details) >= 0)
            {
                this.BaseRemove(details.UsaStateFullName);
                return true;
            }

            return false;
        }

        public void RemoveAt(int index)
        {
            this.BaseRemoveAt(index);
        }

        public void Remove(string name)
        {
            this.BaseRemove(name);
        }

        public void Clear()
        {
            this.BaseClear();
        }

        public bool Contains(UsaStateDefinitionConfigurationElement item)
        {
            if (this.IndexOf(item) >= 0)
            {
                return true;
            }

            return false;
        }

        public void CopyTo(UsaStateDefinitionConfigurationElement[] array, int arrayIndex)
        {
            throw new NotImplementedException();
        }

        public void Insert(int index, UsaStateDefinitionConfigurationElement item)
        {
            this.BaseAdd(index, item);
        }

        public new IEnumerator<UsaStateDefinitionConfigurationElement> GetEnumerator()
        {
            int count = this.Count;

            for (int i = 0; i < count; i++)
            {
                yield return this.BaseGet(i) as UsaStateDefinitionConfigurationElement;
            }
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new UsaStateDefinitionConfigurationElement();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((UsaStateDefinitionConfigurationElement)element).UsaStateFullName;
        }

        protected override void BaseAdd(ConfigurationElement element)
        {
            this.BaseAdd(element, false);
        }
    }
}


/**/




// file="UsaStateDefinitionConfigurationElement.cs"




using System;
using System.ComponentModel;
using System.Configuration;

namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    [System.Diagnostics.DebuggerDisplay("UsaStateFullName = '{UsaStateFullName}'")]
    public class UsaStateDefinitionConfigurationElement : ConfigurationElement
    {
        private const string UsaStateFullNamePropertyName = "usaStateFullName";
        private const string UsaStateAbbreviationPropertyName = "usaStateAbbreviation";
        private const string UsaStateDefinitionUniqueIdentifierPropertyName = "usaStateDefinitionUniqueIdentifier";
        private const string IsContenentialPropertyName = "isContenential";
        private const string CountyLabelNamePropertyName = "countyLabelName";

        private const string UsaCountiesPropertyName = "usaCounties";
        private const string ServiceBusQueuesPropertyName = "serviceBusQueues";

        [ConfigurationProperty(UsaStateFullNamePropertyName, IsRequired = true, IsKey = true)]
        [StringValidator(InvalidCharacters = "~!@#$%^&*()[]{}/;’\"|\\")]
        public string UsaStateFullName
        {
            get { return (string)this[UsaStateFullNamePropertyName]; }
            set { this[UsaStateFullNamePropertyName] = value; }
        }

        [ConfigurationProperty(UsaStateAbbreviationPropertyName, IsRequired = true, IsKey = true)]
        [StringValidator(InvalidCharacters = "  ~!@#$%^&*()[]{}/;’\"|\\")]
        public string UsaStateAbbreviation
        {
            get { return (string)this[UsaStateAbbreviationPropertyName]; }
            set { this[UsaStateAbbreviationPropertyName] = value; }
        }

        [ConfigurationProperty(UsaStateDefinitionUniqueIdentifierPropertyName, IsRequired = true)]
        public int UsaStateDefinitionUniqueIdentifier
        {
            get { return (int)this[UsaStateDefinitionUniqueIdentifierPropertyName]; }
            set { this[UsaStateDefinitionUniqueIdentifierPropertyName] = value; }
        }

        [ConfigurationProperty(IsContenentialPropertyName, IsRequired = true)]
        public bool IsContenential
        {
            get { return (bool)this[IsContenentialPropertyName]; }
            set { this[IsContenentialPropertyName] = value; }
        }

        [ConfigurationProperty(UsaCountiesPropertyName, IsDefaultCollection = false)]
        public UsaCountyCollection UsaCounties
        {
            get { return (UsaCountyCollection)base[UsaCountiesPropertyName]; }
            set { this[UsaCountiesPropertyName] = value; } /* set is here for UnitTests */
        }

        [ConfigurationProperty(CountyLabelNamePropertyName, DefaultValue = UsaCountyLabelEnum.Unknown)]
        [TypeConverter(typeof(CaseInsensitiveEnumConfigurationValueConverter<UsaCountyLabelEnum>))]
        public UsaCountyLabelEnum CountyLabelType
        {
            get
            {
                return (UsaCountyLabelEnum)this[CountyLabelNamePropertyName];
            }

            set
            {
                base[CountyLabelNamePropertyName] = value;
            }
        }
    }
}



/**/




// file="UsaStateDefinitionConfigurationRetriever.cs"




using System;
using System.Configuration;
using System.Linq;

using GranadaCoder.CustomConfigurationExample.Configuration.Interfaces;

namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    public class UsaStateDefinitionConfigurationRetriever : IUsaStateDefinitionConfigurationSectionRetriever
    {
        public static readonly string ConfigurationSectionName = "UsaStateDefinitionConfigurationSectionName";

        public IUsaStateDefinitionConfigurationSection GetIUsaStateDefinitionConfigurationSection()
        {
            UsaStateDefinitionConfigurationSection returnSection = (UsaStateDefinitionConfigurationSection)ConfigurationManager.GetSection(ConfigurationSectionName);
            if (returnSection != null)
            {
                var duplicates = returnSection.IUsaStateDefinitions.GroupBy(i => new { i.UsaStateDefinitionUniqueIdentifier })
                  .Where(g => g.Count() > 1)
                  .Select(g => g.Key);

                if (duplicates.Count() > 1)
                {
                    throw new ArgumentOutOfRangeException("Duplicate UsaStateDefinitionUniqueIdentifier values.", Convert.ToString(duplicates.First().UsaStateDefinitionUniqueIdentifier));
                }

                return returnSection;
            }

            return null;
        }
    }
}


/**/




// file="UsaStateDefinitionConfigurationSection.cs"




using System.Configuration;

using GranadaCoder.CustomConfigurationExample.Configuration.Interfaces;

namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    public class UsaStateDefinitionConfigurationSection : ConfigurationSection, IUsaStateDefinitionConfigurationSection
    {
        [ConfigurationProperty("", IsDefaultCollection = true)]
        public UsaStateDefinitionCollection UsaStateDefinitions
        {
            get
            {
                UsaStateDefinitionCollection coll = (UsaStateDefinitionCollection)base[string.Empty];
                return coll;
            }
        }

        /* Here is the interface property that simply returns the non-interface property from above.  This allows System.Configuration to hydrate the non-interface property, but allows the code to be written (and unit test mocks to be written) against the interface property. */
        public IUsaStateDefinitionCollection IUsaStateDefinitions
        {
            get { return this.UsaStateDefinitions; }
        }
    }
}



/**/




// file="UsaStateDefinitionFinder.cs"




using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Text;

using GranadaCoder.CustomConfigurationExample.Configuration.Interfaces;

namespace GranadaCoder.CustomConfigurationExample.Configuration
{
    public class UsaStateDefinitionFinder : IUsaStateDefinitionFinder
    {
        private const string ErrorMessageMoreThanOneMatch = "More than item was found with the selection criteria. ({0})";

        private const string ErrorMessageNoMatch = "No item was found with the selection criteria. ({0})";

        public UsaStateDefinitionConfigurationElement FindUsaStateDefinitionConfigurationElement(IUsaStateDefinitionConfigurationSection settings, string usaStateFullName)
        {
            UsaStateDefinitionConfigurationElement returnItem = null;

            if (null != settings && null != settings.IUsaStateDefinitions)
            {
                ICollection<UsaStateDefinitionConfigurationElement> matchingFarmItems;
                matchingFarmItems = settings.IUsaStateDefinitions.Where(ele => usaStateFullName.Equals(ele.UsaStateFullName, StringComparison.OrdinalIgnoreCase)).ToList();

                if (matchingFarmItems.Count > 1)
                {
                    string errorDetails = this.BuildErrorDetails(matchingFarmItems);
                    throw new IndexOutOfRangeException(string.Format(ErrorMessageMoreThanOneMatch, errorDetails));
                }

                returnItem = matchingFarmItems.FirstOrDefault();
            }

            return returnItem;
        }

        public UsaStateDefinitionConfigurationElement FindUsaStateDefinitionConfigurationElement(string usaStateFullName)
        {
            IUsaStateDefinitionConfigurationSection settings = new UsaStateDefinitionConfigurationRetriever().GetIUsaStateDefinitionConfigurationSection();
            return this.FindUsaStateDefinitionConfigurationElement(settings, usaStateFullName);
        }

        public UsaStateDefinitionConfigurationElement FindUsaStateDefinitionConfigurationElementByUniqueId(int id)
        {
            IUsaStateDefinitionConfigurationSection settings = new UsaStateDefinitionConfigurationRetriever().GetIUsaStateDefinitionConfigurationSection();
            return this.FindUsaStateDefinitionConfigurationElementByUniqueId(settings, id);
        }

        public UsaStateDefinitionConfigurationElement FindUsaStateDefinitionConfigurationElementByUniqueId(IUsaStateDefinitionConfigurationSection settings, int id)
        {
            UsaStateDefinitionConfigurationElement returnItem = null;

            if (null != settings && null != settings.IUsaStateDefinitions)
            {
                ICollection<UsaStateDefinitionConfigurationElement> matchingFarmItems;
                matchingFarmItems = settings.IUsaStateDefinitions.Where(ele => id == ele.UsaStateDefinitionUniqueIdentifier).ToList();

                if (matchingFarmItems.Count > 1)
                {
                    string errorDetails = this.BuildErrorDetails(matchingFarmItems);
                    throw new IndexOutOfRangeException(string.Format(ErrorMessageMoreThanOneMatch, errorDetails));
                }

                returnItem = matchingFarmItems.FirstOrDefault();
            }

            return returnItem;
        }

        private string BuildErrorDetails(ICollection<UsaStateDefinitionConfigurationElement> items)
        {
            string returnValue;

            StringBuilder sb = new StringBuilder();

            if (null != items)
            {
                foreach (UsaStateDefinitionConfigurationElement item in items)
                {
                    sb.Append(string.Format("UsaStateFullName='{0}'.", item.UsaStateFullName));
                }
            }

            returnValue = sb.ToString();

            return returnValue;
        }
    }
}



/**/




// file="IUsaStateDefinitionCollection.cs"




using System;
using System.Collections.Generic;

namespace GranadaCoder.CustomConfigurationExample.Configuration.Interfaces
{
    public interface IUsaStateDefinitionCollection : IList<UsaStateDefinitionConfigurationElement>, IEnumerable<UsaStateDefinitionConfigurationElement> /* Implement IEnumerable to allow Linq queries */
    {
        UsaStateDefinitionConfigurationElement this[string name] { get; }

        void Remove(string name);
    }
}



/**/




// file="IUsaStateDefinitionConfigurationSection.cs"




using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace GranadaCoder.CustomConfigurationExample.Configuration.Interfaces
{
    public interface IUsaStateDefinitionConfigurationSection
    {
        IUsaStateDefinitionCollection IUsaStateDefinitions { get; }
    }
}


/**/




// file="IUsaStateDefinitionConfigurationSectionRetriever.cs"




namespace GranadaCoder.CustomConfigurationExample.Configuration.Interfaces
{
    public interface IUsaStateDefinitionConfigurationSectionRetriever
    {
        IUsaStateDefinitionConfigurationSection GetIUsaStateDefinitionConfigurationSection();
    }
}



/**/




// file="IUsaStateDefinitionFinder.cs"




using System;

namespace GranadaCoder.CustomConfigurationExample.Configuration.Interfaces
{
    public interface IUsaStateDefinitionFinder
    {
        UsaStateDefinitionConfigurationElement FindUsaStateDefinitionConfigurationElement(IUsaStateDefinitionConfigurationSection settings, string usaStateFullName);

        UsaStateDefinitionConfigurationElement FindUsaStateDefinitionConfigurationElement(string usaStateFullName);

        UsaStateDefinitionConfigurationElement FindUsaStateDefinitionConfigurationElementByUniqueId(int id);

        UsaStateDefinitionConfigurationElement FindUsaStateDefinitionConfigurationElementByUniqueId(IUsaStateDefinitionConfigurationSection settings, int id);
  }
}



/**/




// file="Program.cs"

using System;
using System.Text;

using GranadaCoder.CustomConfigurationExample.Configuration;
using GranadaCoder.CustomConfigurationExample.Configuration.Interfaces;

using log4net;
using Microsoft.Practices.Unity;

namespace GranadaCoder.CustomConfigurationExample.ConsoleAppOne
{
    public static class Program
    {
        public const int UnhandledExceptionErrorCode = 1;

        private static readonly ILog TheLogger = LogManager.GetLogger(typeof(Program));

        public static int Main(string[] args)
        {
            int returnValue = 0;
            string logMsg = string.Empty;

            try
            {
                //// For future //log4net.Config.XmlConfigurator.Configure();
                //// For future //IUnityContainer container = new UnityContainer();
                //// For future //container.RegisterType<ILog>(new InjectionFactory(x => LogManager.GetLogger(typeof(GranadaCoder.CustomConfigurationExample.ConsoleAppOne.Program))));

                IUsaStateDefinitionConfigurationSectionRetriever retr = new UsaStateDefinitionConfigurationRetriever();
                IUsaStateDefinitionConfigurationSection section = retr.GetIUsaStateDefinitionConfigurationSection();

                IUsaStateDefinitionFinder finder = new UsaStateDefinitionFinder();
                UsaStateDefinitionConfigurationElement foundElement = finder.FindUsaStateDefinitionConfigurationElement("Virginia");

                if (null != section)
                {
                    foreach (UsaStateDefinitionConfigurationElement state in section.IUsaStateDefinitions)
                    {
                        Console.WriteLine("state.UsaStateFullName='{0}', state.UsaStateAbbreviation='{1}', state.IsContenential='{2}', state.CountyLabelType='{3}'", state.UsaStateFullName, state.UsaStateAbbreviation, state.IsContenential, state.CountyLabelType);
                        foreach (UsaCountyConfigurationElement county in state.UsaCounties)
                        {
                            Console.WriteLine("county.UsaCountyValue='{0}'", county.UsaCountyValue);
                        }

                        Console.WriteLine("--------------------");
                    }
                }
            }
            catch (Exception e)
            {
                TheLogger.Error(e.Message, e);
                Console.WriteLine("Unexpected Exception : {0}", e.Message);
                returnValue = UnhandledExceptionErrorCode;
            }

            Console.WriteLine("END : {0}", System.Diagnostics.Process.GetCurrentProcess().ProcessName);
            Console.WriteLine(string.Empty);

            Console.WriteLine("Press ENTER to exit");
            Console.ReadLine();

            return returnValue;
        }
    }
}

Answer 2

I finally found this guy's example. It was coded and worked right out of the box.

http://manyrootsofallevilrants.blogspot.com/2011/07/nested-custom-configuration-collections.html

I am going to paste the code here......only because I cannot stand it when someone says "Your answer is here", and the link is dead.

Please try his website first, and leave a "thank you" if it works.

using System;
using System.Configuration;

namespace SSHTunnelWF
{
    public class TunnelSection : ConfigurationSection
    {
        [ConfigurationProperty("", IsDefaultCollection = true)]  
        public HostCollection Tunnels
        {
            get
            {
                HostCollection hostCollection = (HostCollection)base[""];
                return hostCollection;                
            }
        }
    }

    public class HostCollection : ConfigurationElementCollection
    {
        public HostCollection()
        {
            HostConfigElement details = (HostConfigElement)CreateNewElement();
            if (details.SSHServerHostname != "")
            {
                Add(details);
            }
        }

        public override ConfigurationElementCollectionType CollectionType
        {
            get
            {
                return ConfigurationElementCollectionType.BasicMap;
            }
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new HostConfigElement();
        }

        protected override Object GetElementKey(ConfigurationElement element)
        {
            return ((HostConfigElement)element).SSHServerHostname;
        }

        public HostConfigElement this[int index]
        {
            get
            {
                return (HostConfigElement)BaseGet(index);
            }
            set
            {
                if (BaseGet(index) != null)
                {
                    BaseRemoveAt(index);
                }
                BaseAdd(index, value);
            }
        }

        new public HostConfigElement this[string name]
        {
            get
            {
                return (HostConfigElement)BaseGet(name);
            }
        }

        public int IndexOf(HostConfigElement details)
        {
            return BaseIndexOf(details);
        }

        public void Add(HostConfigElement details)
        {
            BaseAdd(details);
        }

        protected override void BaseAdd(ConfigurationElement element)
        {
            BaseAdd(element, false);
        }

        public void Remove(HostConfigElement details)
        {
            if (BaseIndexOf(details) >= 0)
                BaseRemove(details.SSHServerHostname);
        }

        public void RemoveAt(int index)
        {
            BaseRemoveAt(index);
        }

        public void Remove(string name)
        {
            BaseRemove(name);
        }

        public void Clear()
        {
            BaseClear();
        }

        protected override string ElementName
        {
            get { return "host"; }
        }
    }

    public class HostConfigElement:ConfigurationElement
    {
        [ConfigurationProperty("SSHServerHostname", IsRequired = true, IsKey = true)]
        [StringValidator(InvalidCharacters = "  ~!@#$%^&*()[]{}/;’\"|\\")]
        public string SSHServerHostname
        {
            get { return (string)this["SSHServerHostname"]; }
            set { this["SSHServerHostname"] = value; }
        }

        [ConfigurationProperty("username", IsRequired = true)]
        [StringValidator(InvalidCharacters = "  ~!@#$%^&*()[]{}/;’\"|\\")]
        public string Username
        {
            get { return (string)this["username"]; }
            set { this["username"] = value; }
        }

        [ConfigurationProperty("SSHport", IsRequired = true, DefaultValue = 22)]
        [IntegerValidator(MinValue = 1, MaxValue = 65536)]
        public int SSHPort
        {
            get { return (int)this["SSHport"]; }
            set { this["SSHport"] = value; }
        }

        [ConfigurationProperty("password", IsRequired = false)]
        public string Password
        {
            get { return (string)this["password"]; }
            set { this["password"] = value; }
        }

        [ConfigurationProperty("privatekey", IsRequired = false)]
        public string Privatekey
        {
            get { return (string)this["privatekey"]; }
            set { this["privatekey"] = value; }
        }

        [ConfigurationProperty("privatekeypassphrase", IsRequired = false)]
        public string Privatekeypassphrase
        {
            get { return (string)this["privatekeypassphrase"]; }
            set { this["privatekeypassphrase"] = value; }
        }

        [ConfigurationProperty("tunnels", IsDefaultCollection = false)]
        public TunnelCollection Tunnels
        {
            get { return (TunnelCollection)base["tunnels"]; }
        }
    }

    public class TunnelCollection : ConfigurationElementCollection
    {
        public new TunnelConfigElement this[string name]
        {
            get
            {
                if (IndexOf(name) < 0) return null;
                return (TunnelConfigElement)BaseGet(name);
            }
        }

        public TunnelConfigElement this[int index]
        {
            get { return (TunnelConfigElement)BaseGet(index); }
        }

        public int IndexOf(string name)
        {
            name = name.ToLower();

            for (int idx = 0; idx < base.Count; idx++)
            {
                if (this[idx].Name.ToLower() == name)
                    return idx;
            }
            return -1;
        }

        public override ConfigurationElementCollectionType CollectionType
        {
            get { return ConfigurationElementCollectionType.BasicMap; }
        }

        protected override ConfigurationElement CreateNewElement()
        {
            return new TunnelConfigElement();
        }

        protected override object GetElementKey(ConfigurationElement element)
        {
            return ((TunnelConfigElement)element).Name;
        }

        protected override string ElementName
        {
            get { return "tunnel"; }
        }
    }

    public class TunnelConfigElement : ConfigurationElement
    {        
        public TunnelConfigElement()
        {
        }

        public TunnelConfigElement(string name, int localport, int remoteport, string destinationserver)
        {
            this.DestinationServer = destinationserver;
            this.RemotePort = remoteport;
            this.LocalPort = localport;            
            this.Name = name;
        }

        [ConfigurationProperty("name", IsRequired = true, IsKey = true, DefaultValue = "")]       
        public string Name
        {
            get { return (string)this["name"]; }
            set { this["name"] = value; }
        }        

        [ConfigurationProperty("localport", IsRequired = true, DefaultValue =1)]
        [IntegerValidator(MinValue = 1, MaxValue = 65536)]
        public int LocalPort
        {
            get { return (int)this["localport"]; }
            set { this["localport"] = value; }
        }

        [ConfigurationProperty("remoteport", IsRequired = true, DefaultValue =1)]
        [IntegerValidator(MinValue = 1, MaxValue = 65536)]
        public int RemotePort
        {
            get { return (int)this["remoteport"]; }
            set { this["remoteport"] = value; }
        }

        [ConfigurationProperty("destinationserver", IsRequired = true)]
        [StringValidator(InvalidCharacters = "  ~!@#$%^&*()[]{}/;’\"|\\")]
        public string DestinationServer
        {
            get { return (string)this["destinationserver"]; }
            set { this["destinationserver"] = value; }
        }
    }
}

And the configuration code

 <?xml version="1.0"?>
 <configuration>
   <configSections>
     <section name="TunnelSection" type="SSHTunnelWF.TunnelSection,SSHTunnelWF" />
   </configSections>
   <TunnelSection>
     <host SSHServerHostname="tsg.edssdn.net" username="user" SSHport="22" password="pass" privatekey="" privatekeypassphrase="">
       <tunnels>
         <tunnel name="tfs" localport="8081"  remoteport="8080" destinationserver="tfs2010.dev.com"  />
         <tunnel name="sql" localport="14331"  remoteport="1433" destinationserver="sql2008.dev.com"  />
         <tunnel name="crm2011app" localport="81"  remoteport="80" destinationserver="crm2011betaapp.dev.com"  />
       </tunnels>
     </host>
     <host SSHServerHostname="blade16" username="root" SSHport="22"  password="pass" privatekey="" privatekeypassphrase="">
      <tunnels>
        <tunnel name="vnc" localport="5902"  remoteport="5902" destinationserver="blade1.dev.com" />
      </tunnels>
     </host>
   </TunnelSection>
 </configuration>

And then the "call"

TunnelSection tunnels = ConfigurationManager.GetSection("TunnelSection") as TunnelSection