我在哪里弄错了？

Question

我在同一解决方案的3层体系结构中有3个项目。

但是我无法在演示文稿层中显示我的演示文稿我收到错误CS0103，我的想法是该层无法访问其引用的层中使用的方法。如果是这种情况，那么我该如何引用这些方法或建议一种简便的方法呢？

我的表示层引用了以下代码

using Data_Link;
using static Data_Link.Program;
using Microsoft.VisualBasic.FileIO;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace Business_Logic
{
    public class Program 
    {


        List<Card> CrackableCards = GetCrackablePINS(AllCards);
        List<Card> ExpiredCards = GetExpiredCards(AllCards);
        List<Card> ExpiringCards = GetExpiringCards(AllCards);
        List<Card> HNWIs = GetHNWI(AllCards);

        public static List<Card> AllCards { get; private set; }

        /* List<Card> AllCards = new List<Card>();
         public int[] computeFrequency(List<LotteryEntry> historicalData)
         public static 

         */
        //Returns crackable pins
        private static List<Card> GetCrackablePINS(List<Card> cards)
        {
            List<Card> CrackableCards = GetCrackablePINS(AllCards);
            List<Card> results = new List<Card>();
            foreach (var card in cards)
            {
                if (IsCrackable(card.CardPIN))
                    results.Add(card);
            }
            return results;

        }
        //Returns expired cards
        private static List<Card> GetExpiredCards(List<Card> cards)
        {
            List<Card> results = new List<Card>();
            foreach (var card in cards)
            {
                if (HasExpired(card.ExpiryDate))
                    results.Add(card);
            }
            return results;
        }
        //Returns expiring cards
        private static List<Card> GetExpiringCards(List<Card> cards)
        {
            List<Card> results = new List<Card>();
            foreach (var card in cards)
            {
                if (IsExpiring(card.ExpiryDate))
                    results.Add(card);
            }
            return results;
        }
        //Returns HNWIs
        private static List<Card> GetHNWI(List<Card> cards)
        {
            List<Card> results = new List<Card>();
            foreach (var card in cards)
            {
                if (IsHNWI(card.CardLimit))
                    results.Add(card);
            }
            return results;
        }
        //Generates report in csv
         private void GenerateReport(List<Card> cardCriteria, string fileName)
        {
            string heading = "Card Type Code,Card Type Full Name,Issuing Bank,Card Number,Card Holder's Name,CVV/CVV2,Issue Date,Expiry Date,Billing Date,Card PIN,Credit Limit";
            File.WriteAllText(fileName, heading);
            foreach (var card in cardCriteria)
            {
                try
                {
                    string details = card.CardTypeCode + "," + card.CardTypeFullName + "," + card.IssusingBank + "," + card.CardNumber + "," + card.CardHolderName + "," + card.CVV + "," + card.IssueDate + "," + card.ExpiryDate + "," + card.BillingDate + "," + card.CardPIN + "," + card.CardLimit;
                    File.AppendAllText(fileName, details);
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                }
            }
        }
        //Checks if a card pin is crackable
        private static bool IsCrackable(string PIN)
        {
            if (PIN[0] == PIN[1] || PIN[1] == PIN[2] || PIN[2] == PIN[3])
            {
                return true;
            }
            else if ((int)PIN[0] == (int)PIN[1] - 1 && (int)PIN[1] == (int)PIN[2] - 1 && (int)PIN[2] == PIN[3] - 1)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        //Checks if the card has expired
        private static bool HasExpired(string date)
        {
            string[] dateString = date.Split('/');
            int month = int.Parse(dateString[0]);
            int year = int.Parse(dateString[1]);
            if (month <= 2 && year <= 2020)
                return true;
            else
                return false;
        }
        //Checks if the card is expiring
        private static bool IsExpiring(string date)
        {
            string[] dateString = date.Split('/');
            int month = int.Parse(dateString[0]);
            int year = int.Parse(dateString[1]);
            if (month == DateTime.Now.Month && year == DateTime.Now.Year)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        //Checks if a card is an HNWI
        private static bool IsHNWI(int HNWI)
        {
            const int limit = 149999;
            if (HNWI > limit)
                return true;
            else
                return false;
        }
    }
}

Answer 1

您正在使用静态BusinessLogic.Program，将允许访问public static的BusinessLogic.Program成员。

但是，您的字段（ExpiredCards等）是非静态的，并且是private（默认情况下）。在每一项之前都添加public static。

也就是说，避免静态数据可能更易于维护。而是在BusinessLogic.Program中创建和创建Main()的实例。