无法将类型为“ Common.Date”的对象转换为类型为“ System.IConvertible C＃”

Question

我已经在stackoverflow中看到了此错误消息问题，但是它们都不是针对datetime或date类型的，以便仅与date类型一起工作。我制作了date类型的类，并在date类中为其编写了一些重载。 我的约会班是

using System;
namespace Common 
{
    public class Date
    {
        private DateTime _d1;

        public Date(DateTime dateTime)
        {
            _d1 = dateTime;
        }

        public static bool operator <(Date date1, Date date2)
        {
            bool flag = false;


            //Now, get the original DateTime Type of C#
            DateTime firstDate = Convert.ToDateTime(date1);
            DateTime secondDate = Convert.ToDateTime(date2);

            //Now compare the two DateTime variables and assign the flag to true 
            //if the first date is smaller than the second date
            int result = DateTime.Compare(firstDate, secondDate);
            if (result < 0)
            {
                flag = true;
            }
            return flag;
        }

        public static bool operator >(Date date1, Date date2)
        {
            bool flag = false;

            //Now, get the original DateTime Type of C#
            DateTime firstDate = Convert.ToDateTime(date1);
            DateTime secondDate = Convert.ToDateTime(date2);

            //Now compare the two DateTime variables and assign the flag to true 
            //if the first date is Greater than the second date
            int result = DateTime.Compare(firstDate, secondDate);
            if (result > 0)
            {
                flag = true;
            }
            return flag;
        }

        public static bool operator <=(Date date1, Date date2)
        {
            bool flag = false;

            //Now, get the original DateTime Type of C#
            DateTime firstDate = Convert.ToDateTime(date1);
            DateTime secondDate = Convert.ToDateTime(date2);

            //Now compare the two DateTime variables and assign the flag to true 
            //if the first date is Greater than the second date
            int result = DateTime.Compare(firstDate, secondDate);
            if (result <= 0)
            {
                flag = true;
            }

            return flag;
        }

        public static bool operator >=(Date date1, Date date2)
        {
            bool flag = false;

            //Now, get the original DateTime Type of C#
            DateTime firstDate = Convert.ToDateTime(date1);
            DateTime secondDate = Convert.ToDateTime(date2);

            //Now compare the two DateTime variables and assign the flag to true 
            //if the first date is Greater than the second date
            int result = DateTime.Compare(firstDate, secondDate);
            if (result >= 0)
            {
                flag = true;
            }
            return flag;
        }

        public static bool operator ==(Date date1, Date date2)
        {
            bool flag = false;

            //Now, get the original DateTime Type of C#
            DateTime firstDate = Convert.ToDateTime(date1);
            DateTime secondDate = Convert.ToDateTime(date2);

            //Now compare the two DateTime variables and assign the flag to true 
            //if the first date is Greater than the second date
            int result = DateTime.Compare(firstDate, secondDate);
            if (result == 0)
            {
                flag = true;
            }
            return flag;
        }

        public static bool operator !=(Date date1, Date date2)
        {
            bool flag = false;

            //Now, get the original DateTime Type of C#
            DateTime firstDate = Convert.ToDateTime(date1);
            DateTime secondDate = Convert.ToDateTime(date2);

            //Now compare the two DateTime variables and assign the flag to true 
            //if the first date is Greater than the second date
            int result = DateTime.Compare(firstDate, secondDate);
            if (result != 0)
            {
                flag = true;
            }
            return flag;
        }
    }//end of class Date
}//End of namespace

但是问题是当我试图在页面后面的代码中使用它时，会给我这个错误-无法将类型为'Common.Date'的对象转换为类型为'System.IConvertible

我在其中使用它的代码，例如Date PurchaseDate = new Date（item.PurchaseDate）; 日期SubmitSate =新的Date（item.SubmissionDate）;

                    if (purchaseDate>submissionSate)
                    {
                        //to do
                    }

这在item对象中，purchateate和submision日期是datetime属性，并且错误在if行中有人可以提供我任何建议吗？ 这个问题的可能解决方案是什么？

Answer 1

您可以直接访问Date字段。 尽管我对此Date对象的有用性表示怀疑。

public static bool operator <(Date date1, Date date2)
{
    return date1 != null && date2 != null && date1._d1 < date2._d1
}

Answer 2

在>运算符重载中，

DateTime firstDate = Convert.ToDateTime(date1); 
DateTime secondDate = Convert.ToDateTime(date2);

并且没有携带您的Date对象的Convert.ToDateTime重载，因此您正在调用Convert.ToDateTime(object) ，这需要object实现IConvertible 。

您可以实现IConvertible ，或者只比较@ChaosPandion提到的_d1值。