为什么继承自DataGridViewColumn的自定义Column总是无法保存属性值

 public class TXDataGridViewNumericColumn : DataGridViewColumn
    {
        public TXDataGridViewNumericColumn() : base(new TXNumericCell())
        {
            this.InputType = NumericType.Integer; 
            this.CellTemplate=new TXNumericCell(); 
        }
        
        public override DataGridViewCell CellTemplate
        {
            get
            {
                return base.CellTemplate;
            }
            set
            {
                if (value != null &&
                    !value.GetType().IsAssignableFrom(typeof(TXNumericCell)))
                {
                    throw new InvalidCastException("Must be a NumericCell");
                }
                base.CellTemplate = value;
            }        }        private NumericType m_NumericType;        
        public enum NumericType
        {
            Decimal,
            Integer,
            PositiveDecimal,
            NegativeDecimal,
            PositiveInteger,
            NegativeInteger
        }        
        public NumericType InputType
        {
            get { return m_NumericType; }
            set { m_NumericType = value; }
        }
}当在datagridview的列编辑器中选择列的InputType属性时(在设计模式时)，其值不可以保存？请问哪里有问题？谢谢！