调试易

拜服各位大虾，帮帮忙解决下这问题。。这是自定义控件的代码using System.ComponentModel;
using System.Windows.Forms;namespace WinForm
{
    public partial class NumTextBox : TextBox
    {
        private static readonly NumberScope defaultNum = new NumberScope(0, 100);        private NumberScope numRange = defaultNum;        [Category("Vaildation")]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
        public NumberScope NumRange
        {
            get { return numRange; }
            set { numRange = value; }
        }        public void ResetNumRange()
        {
            numRange = defaultNum;
        }        public bool ShouleSerializeNumRange()
        {
            return !NumRange.Equals(defaultNum);
        }        [Browsable(false)]
        public bool ContentsInRange
        {
            get { return NumRange.Validate(Text); }
        }        public NumTextBox()
        {
            InitializeComponent();
        }
    }    [TypeConverter(typeof(NumberScopeConvertor))]
    public class NumberScope
    {
        private double low;
        public double Low
        {
            get { return low; }
            set { low = value; }
        }        private double high;
        public double High
        {
            get { return high; }
            set { high = value;}
        }        public NumberScope(double low, double high)
        {
            this.high = high;
            this.low = low;
        }        public bool Validate(string num)
        {
            double tmp = double.Parse(num);
            if (tmp < high && tmp > low)
                return true;
            else
                return false;
        }        public override string ToString()
        {
            return string.Format("{0},{1}", Low, High);
        }
    }
} public class NumberScopeConvertor:TypeConverter
    {
        public override bool CanConvertFrom(ITypeDescriptorContext context, 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)
            {
                string[] numStr = ((string)value).Split(new char[] { ',' });
                if (numStr.Length != 2)
                {
                    throw new Exception("invalid format value");
                }
                else
                {
                    try
                    {
                        double low = double.Parse(numStr[0]);
                        double high = double.Parse(numStr[1]);
                        return new NumberScope(low, high);
                    }
                    catch (FormatException)
                    {
                        throw new FormatException("format value to NumberScope faild");
                    }
                }
            }
            return base.ConvertFrom(context, culture, value);
        }        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(string))
                return true;
            if (destinationType == typeof(InstanceDescriptor))
                return true;
            return base.CanConvertTo(context, destinationType);
        }        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType == typeof(string))
                return ((NumberScope)value).ToString();
            if (destinationType == typeof(InstanceDescriptor))
            {
                ConstructorInfo ci = typeof(NumberScope).GetConstructor(new Type[] { typeof(double), typeof(double) });
                NumberScope scope = (NumberScope)value;
                return new InstanceDescriptor(ci, new object[] { scope.Low, scope.High });
            }
            return base.ConvertTo(context, culture, value, destinationType);
        }        public override bool GetPropertiesSupported(ITypeDescriptorContext context)
        {
            return true;
        }        public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)
        {
            PropertyDescriptorCollection propertys = TypeDescriptor.GetProperties(typeof(NumberScope), attributes);
            return propertys;
        }
    }之后在一个form上使用这个控件，打开这个控件的属性修改NumRange属性，Ctrl+S保存的时候会报错
报错内容为：
Code generation for property 'NumRange' failed. Error was: '[A]WinForm.NumberScope cannot be cast to [B]WinForm.NumberScope. Type A originates from 'WinForm, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' in the context 'LoadNeither' at location 'C:\Users\CHUNSIBO\AppData\Local\Microsoft\VisualStudio\10.0\ProjectAssemblies\elgwjxaa01\WinForm.exe'. Type B originates from 'WinForm, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' in the context 'LoadNeither' at location 'C:\Users\ss\AppData\Local\Microsoft\VisualStudio\10.0\ProjectAssemblies\ko-pdm2_01\WinForm.exe'.'