Something

using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.Globalization;
using System.ComponentModel.Design.Serialization;
using System.Reflection;


namespace Grafikon
{

    public class IntervalConverter : ExpandableObjectConverter
    {
        public override bool CanConvertTo(ITypeDescriptorContext context,
                                              System.Type destinationType)
        {
            if (destinationType == typeof(cInterval)) return true;
            if (destinationType == typeof(InstanceDescriptor)) return true;

            return base.CanConvertTo(context, destinationType);
        }

        public override object ConvertTo(ITypeDescriptorContext context,
                               CultureInfo culture,
                               object value,
                               System.Type destinationType)
        {
            if (destinationType == typeof(System.String) && (value is cInterval))
            {
                cInterval i = (cInterval)value;
                String s = String.Format("{0}; {1}", i.Min, i.Max);
                return s;
            }

            if ((destinationType == typeof(InstanceDescriptor) && (value is cInterval)))
            {
                cInterval i = (cInterval)value;

                Object[] Properties = new Object[2];
                Type[] Types = new Type[2];

                Types[0] = typeof(float);
                Types[1] = typeof(float);

                Properties[0] = i.Min;
                Properties[1] = i.Max;




                ConstructorInfo ci = typeof(cInterval).GetConstructor(Types);

                if (ci == null) throw new Exception("FASZ");

                return new InstanceDescriptor(ci, Properties, true);
            }

            return base.ConvertTo(context, culture, value, destinationType);
        }

        public override bool CanConvertFrom(ITypeDescriptorContext context,
                              System.Type sourceType)
        {
            if (sourceType == typeof(string))
                return true;

            return base.CanConvertFrom(context, sourceType);
        }

        public override object ConvertFrom(ITypeDescriptorContext context,
                              CultureInfo culture, object value)
        {
            if (value is string)
            {
                try
                {
                    string s = (string)value;
                    int semicolon = s.IndexOf(';');

                    if (semicolon != -1)
                    {
                        float min = Single.Parse(s.Substring(0, semicolon));
                        float max = Single.Parse(s.Substring(semicolon + 1));

                        cInterval i = new cInterval(min, max);
                        return i;
                    }
                }
                catch
                {
                    throw new ArgumentException(
                        "Can not convert '" + (string)value +
                                           "' to type SpellingOptions");
                }
            }
            return base.ConvertFrom(context, culture, value);
        }



    }



    [TypeConverterAttribute(typeof(IntervalConverter))]    
    public struct cInterval
    {
        private float _min, _max;
        public float Min { get { return _min; } set { _min = value; } }
        public float Max { get { return _max; } set { _max = value; } }

        public cInterval(float min, float max)
        {
            _min = min;
            _max = max;
        }



    }
}