ConfigurationConverterBase Class

using System;
using System.Collections.Generic;
using System.Text;
using System.Configuration;
using System.Globalization;
using System.ComponentModel;


public sealed class CustomTimeSpanMinutesConverter :
    ConfigurationConverterBase
{
    internal bool ValidateType(object value, 
        Type expected)
    {
        bool result;

        if ((value != null) &&
            (value.GetType() != expected))
            result = false;
        else
            result = true;

        return result;
    }

    public override bool CanConvertTo(
        ITypeDescriptorContext ctx, Type type)
    {
        return (type == typeof(string));
    }

    public override bool CanConvertFrom(
        ITypeDescriptorContext ctx, Type type)
    {
        return (type == typeof(string));
    }

    public override object ConvertTo(
        ITypeDescriptorContext ctx, CultureInfo ci,
        object value, Type type)
    {
        ValidateType(value, typeof(TimeSpan));

        long data = (long)(((TimeSpan)value).TotalMinutes);

        return data.ToString(CultureInfo.InvariantCulture);
    }

    public override object ConvertFrom(
        ITypeDescriptorContext ctx, CultureInfo ci, object data)
    {

        long min = long.Parse((string)data,
            CultureInfo.InvariantCulture);

        return TimeSpan.FromMinutes((double)min);
    }

}

    // Define a custom section.
    public sealed class CustomSection :
        ConfigurationSection
    {

        public CustomSection() 
        {

        }

        [ConfigurationProperty("fileName", DefaultValue="   default.txt  ")]
        [TypeConverter(typeof(WhiteSpaceTrimStringConverter))]
        public String FileName
        {
            get
            {
                return (String)this["fileName"];
            }
            set
            {
                this["fileName"] = value;
            }
        }

        [ConfigurationProperty("maxIdleTime")]
        [TypeConverter(typeof(CustomizedTimeSpanMinutesConverter))]
        public TimeSpan MaxIdleTime
        {
            get
            {
                return (TimeSpan)this["maxIdleTime"];
            }
            set
            {
                this["maxIdleTime"] = value;
            }
        }

        [ConfigurationProperty("timeDelay", 
            DefaultValue = "infinite")]
        [TypeConverter(typeof(InfiniteTimeSpanConverter))]
        public TimeSpan TimeDelay
        {
            get
            {
                return (TimeSpan)this["timeDelay"];
            }
            set
            {
                this["timeDelay"] = value;
            }
        }

        [ConfigurationProperty("cdStr", 
            DefaultValue = "str0, str1",
           IsRequired = true)]

        [TypeConverter(typeof(
            CommaDelimitedStringCollectionConverter))]
        public StringCollection CdStr
        {
            get
            {
                return (StringCollection)this["cdStr"];
            }

            set
            {
                this["cdStr"] = value;
            }

        }



        public enum Permissions
        {
            FullControl         = 0,
            Modify              = 1,
            ReadExecute         = 2,
            Read                = 3,
            Write               = 4,
            SpecialPermissions  = 5
        }

        [ConfigurationProperty("permission", DefaultValue = Permissions.Read)]
        public Permissions Permission
        {
            get
            {
                return (Permissions)this["permission"];
            }

            set
            {
                this["permission"] = value;
            }

        }


        [ConfigurationProperty("maxUsers", DefaultValue="infinite")]
        [TypeConverter(typeof(InfiniteIntConverter))]
        public int MaxUsers
        {
            get
            {
                return (int)this["maxUsers"];
            }
            set
            {
                this["maxUsers"] = value;
            }
        }

    }

}

using System;
using System.Collections.Generic;
using System.Text;
using System.Configuration;
using System.Globalization;
using System.ComponentModel;

namespace Samples.AspNet
{

    // Define a custom section.
    public sealed class CustomSection :
        ConfigurationSection
    {

        public CustomSection()
        { }

        [ConfigurationProperty("fileName", DefaultValue = "default.txt",
            IsRequired = true, IsKey = false)]
        [StringValidator(InvalidCharacters = " ~!@#$%^&*()[]{}/;'\"|\\",
            MinLength = 1, MaxLength = 60)]
        public string FileName
        {
            get
            {
                return (string)this["fileName"];
            }
            set
            {
                this["fileName"] = value;
            }
        }


        [ConfigurationProperty("maxIdleTime")]
        [TypeConverter(typeof(TsMinutesConverter))]
        public TimeSpan MaxIdleTime
        {
            get
            {
                return (TimeSpan)this["maxIdleTime"];
            }
            set
            {
                this["maxIdleTime"] = value;
            }
        }

    }

    public sealed class TsMinutesConverter :
        ConfigurationConverterBase
    {
        internal bool ValidateType(object value, Type expected)
        {
            bool result;

            if ((value != null) &&
                (value.GetType() != expected))
                result = false;
            else
                result = true;

            return result;
        }

        public override bool CanConvertTo(
            ITypeDescriptorContext ctx, Type type)
        {
            return (type == typeof(string));
        }

        public override bool CanConvertFrom(
            ITypeDescriptorContext ctx, Type type)
        {
            return (type == typeof(string));
        }

        public override object ConvertTo(
            ITypeDescriptorContext ctx, CultureInfo ci,
            object value, Type type)
        {
            ValidateType(value, typeof(TimeSpan));

            long data = (long)(((TimeSpan)value).TotalMinutes);

            return data.ToString(CultureInfo.InvariantCulture);
        }

        public override object ConvertFrom(
            ITypeDescriptorContext ctx, CultureInfo ci, object data)
        {

            long min = long.Parse((string)data,
                CultureInfo.InvariantCulture);

            return TimeSpan.FromMinutes((double)min);
        }
    }

    class UsingConfigutationConverterBase
    {

        // Create a custom section.
        static void CreateSection()
        {
            try
            {

                CustomSection customSection;

                // Get the current configuration file.
                System.Configuration.Configuration config =
                        ConfigurationManager.OpenExeConfiguration(
                        ConfigurationUserLevel.None);

                // Create the section entry  
                // in the <configSections> and the 
                // related target section in <configuration>.
                if (config.Sections["CustomSection"] == null)
                {
                    customSection = new CustomSection();
                    config.Sections.Add("CustomSection", customSection);
                    customSection.SectionInformation.ForceSave = true;
                    config.Save(ConfigurationSaveMode.Full);
                }
            }
            catch (ConfigurationErrorsException err)
            {
                Console.WriteLine(err.ToString());
            }

        }


        // Change custom section and write it to disk.
        static void SerializeCustomSection()
        {
            try
            {
                System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None);

                CustomSection customSection =
                    config.Sections.Get("CustomSection")
                    as CustomSection;

                TimeSpan ts =
                    new TimeSpan(1, 30, 30);

                customSection.MaxIdleTime = ts;

                config.Save();

                string maxIdleTime =
                    customSection.MaxIdleTime.ToString();

                Console.WriteLine("New max idle time: {0}",
                    maxIdleTime);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }

        }

        // Read custom section from disk.
        static void DeserializeCustomSection()
        {

            try
            {
                System.Configuration.Configuration config =
                    ConfigurationManager.OpenExeConfiguration(
                    ConfigurationUserLevel.None);

                CustomSection customSection =
                    config.Sections.Get("CustomSection")
                    as CustomSection;

                TimeSpan maxIdleTime =
                    customSection.MaxIdleTime;


                Console.WriteLine("Max idle time: {0}",
                    maxIdleTime.ToString());
            }
            catch (Exception e)
            {
                Console.WriteLine(e.ToString());
            }

        }


        static void Main(string[] args)
        {
            CreateSection();
            SerializeCustomSection();
            DeserializeCustomSection();

        }
    }
}