TypeConvert Demo

下班了，先把代码贴上

Code
[TypeConverter(typeof(AddressConverter))]
    public class Address
    {
        public Address() { }

        public Address(string street, string city,string state, string zip)
        {
            this.street = street;
            this.city = city;
            this.state = state;
            this.zip = zip;
        }

        private String street = null;
        private String city = null;
        private String state = null;
        private String zip = null;

        [NotifyParentProperty(true)]
        public String Street
        {
            get
            {
                return street;
            }
            set
            {
                street = value;
            }
        }

        [NotifyParentProperty(true)]
        [TypeConverter(typeof(CityConverter))]
        public String City
        {
            get
            {
                return city;
            }
            set
            {
                city = value;
            }
        }

        [NotifyParentProperty(true)]
        public String State
        {
            get
            {
                return state;
            }
            set
            {
                state = value;
            }
        }

        [NotifyParentProperty(true)]
        public String Zip
        {
            get
            {
                return zip;
            }
            set
            {
                zip = value;
            }
        }

        public override string ToString()
        {
            return this.ToString(CultureInfo.CurrentCulture);
        }

        protected virtual string ToString(CultureInfo culture)
        {
            return TypeDescriptor.GetConverter(typeof(Address)).ConvertToString(null,culture,this);
        }
    }

    /**//// <summary>
    /// 自定义类型转换器
    /// </summary>
    public class AddressConverter : ExpandableObjectConverter
    {
        /**//// <summary>
        /// 
        /// </summary>
        /// <param name="context"></param>
        /// <param name="sourceType">sourceType表示要转换的类型</param>
        /// <returns>返回值能否将String类型转换为Address类型</returns>
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            if(sourceType==typeof(string))
            {
                return true;
            }
            return base.CanConvertFrom(context, sourceType);
        }

        /**//// <summary>
        /// 
        /// </summary>
        /// <param name="context"></param>
        /// <param name="destinationType">表示要转换到的类型</param>
        /// <returns>返回值能否将Address类型转换为String类型</returns>
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(string))
            {
                return true;
            }
            return base.CanConvertTo(context, destinationType);
        }

        /**//// <summary>
        /// 
        /// </summary>
        /// <param name="context"></param>
        /// <param name="culture"></param>
        /// <param name="value">value为要转换的类型</param>
        /// <returns>将String类型转换为Address类型</returns>
        public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)
        {
            if (value == null)
                return new Address();

            if (value is string)
            {
                string s = (string)value;
                if (s.Length == 0)
                    return new Address();

                string[] parts = s.Split(culture.TextInfo.ListSeparator[0]);
                if (parts.Length != 4)
                    throw new ArgumentException();

                TypeConverter stringConverter = TypeDescriptor.GetConverter(typeof(string));
                
                return new Address((string)stringConverter.ConvertFromString(context,culture,parts[0]),
                    (string)stringConverter.ConvertFromString(context,culture,parts[1]),
                    (string)stringConverter.ConvertFromString(context,culture,parts[2]),
                    (string)stringConverter.ConvertFromString(context,culture,parts[3])
                    );
            }

            return base.ConvertFrom(context, culture, value);
        }

        /**//// <summary>
        /// 将Address类型转换为String类型
        /// </summary>
        /// <param name="context"></param>
        /// <param name="culture"></param>
        /// <param name="value">value为要转换的类型</param>
        /// <param name="destinationType"></param>
        /// <returns></returns>
        public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
        {
            if (value != null)
            {
                if (!(value is Address))
                {
                    throw new ArgumentException();
                }
            }

            if(destinationType==typeof(string))
            {
                if (value == null)
                    return string.Empty;

                Address ad = (Address)value;
                TypeConverter stringConverter = TypeDescriptor.GetConverter(typeof(string));
                return string.Join(culture.TextInfo.ListSeparator,
                    new string[] { 
                        stringConverter.ConvertToString(context,culture,ad.State),
                        stringConverter.ConvertToString(context,culture,ad.City),
                        stringConverter.ConvertToString(context,culture,ad.Street),
                        stringConverter.ConvertToString(context,culture,ad.Zip),
                    });
            }

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

    /**//// <summary>
    /// 
    /// </summary>
    public class CityConverter : StringConverter
    {
        /**//// <summary>
        /// 返回此对象是否支持可以从列表中选取的标准值集
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
        {
            return true;
        }

        /**//// <summary>
        /// 返回下拉框集合类
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public override TypeConverter.StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
        {
            return new StandardValuesCollection(new string[] 
                {
                    "naxx",
                    "mx",
                    "bwl" 
                });
        }

        /**//// <summary>
        /// 标准值的集合是否为独占列表
        /// 默认为flase,为true则表示无法修改列表值
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context)
        {
            return false;//false可自定义内容 true只能选择下拉列表内容
        }
    }