C＃针对分支对象的多个记录

Question

将客户记录添加到它访问的（一些杂货店的）分支中。 如果客户访问多个分支，则将其添加到具有不同ID的多个分支中。 现在我的问题是，无论访问哪个分支以及访问多少个分支，我如何才能只拥有一份客户记录。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Console47
{
    class Customer
    {
        public Guid CustomerID { get; set; }
        public string CustomerName { get; set; }
        public string CustomerAddress { get; set; }
        public string CustomerEmail { get; set; }
        public string CustomerTelNo { get; set; }

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Console47
{
    class Branch
    {
        public Guid BranchID { get; set; }
        public string BranchName { get; set; }
        public string BranchAddress { get; set; }
        public string BranchTelNo { get; set; }

        public List<Customer> customers = new List<Customer>();


        public void AddCustomer()
        {
            var customer = new Customer();

            Console.Write("\nEnter No of customers you want to Add: ");

            var input = Convert.ToInt32(Console.ReadLine());

            Console.WriteLine("\nPlease remember to Enter input in the following order:\n");


            for (int i = 0; i < input; i++)
            {
                Console.WriteLine("1-Customer Name:   2-Customer Address:   3-Customer Telno.:   4-Customer Email:   5-:Branch Name:\n");
                customers.Add(new Customer()
                {

                    CustomerID = Guid.NewGuid(),
                    CustomerName = Console.ReadLine(),
                    CustomerAddress = Console.ReadLine(),
                    CustomerTelNo = Console.ReadLine(),
                    CustomerEmail = Console.ReadLine(),

                });

            }
            Console.WriteLine("***************************");

        }
        public void SearchCustomer()

        {
            Console.Write("\nEnter the name of the customer to find out which branch it is related to:");

            var Cname = Console.ReadLine();

            foreach (var Customeritem in customers)
            {
                if (Cname == Customeritem.CustomerName )
                {
                    Console.WriteLine("\nCustomer ID:{0}\nCustomer Name:{1}\nCustomer Address:{2}\nCustomer Tel. No:{3}\nCustomer Email:{4}\n", Customeritem.CustomerID, Customeritem.CustomerName,Customeritem.CustomerAddress,Customeritem.CustomerTelNo,Customeritem.CustomerEmail);
                    Console.Write("\nCustomer found");
                }
                else if (Cname != Customeritem.CustomerName)
                {
                    Console.Write("Customer Not found");
                }
            }

        }

        public void DeleteCustomer()
        {

            Console.Write("To delete customer, enter name of the customer:");
            var Cname = Console.ReadLine();

            for (int i = 0; i < customers.Count; i++)
            {
                if (customers[i].CustomerName == Cname)
                {
                    customers.RemoveAt(i);
                    Console.Write("Customer found and deleted");
                    break;
                }
                else if (Cname != customers[i].CustomerName)
                {
                    Console.Write("Customer Not found");
                }
            }

        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Console47
{
    class Program
    {
        static void Main(string[] args)
        {
            /***********Add branches************/

            List<Branch> branches = new List<Branch>();


            var branch = new Branch();

            Console.WriteLine("************************");
            Console.WriteLine("Total Branches of Lidel:");
            Console.WriteLine("************************\n");

            var branch1 = new Branch()
            {

                BranchID = Guid.NewGuid(),
                BranchName = "lidel1",
                BranchAddress = "ejbyvej 27",
                BranchTelNo = "55223366",

            };
            branches.Add(branch1);

            var branch2 = new Branch()
            {

                BranchID = Guid.NewGuid(),
                BranchName = "lidel2",
                BranchAddress = "kirkevej 45",
                BranchTelNo = "77885544",

            };
            branches.Add(branch2);
            var branch3 = new Branch()
            {

                BranchID = Guid.NewGuid(),
                BranchName = "lidel3",
                BranchAddress = "kirkevej 12",
                BranchTelNo = "553366611",

            };
            branches.Add(branch3);


            for (int i = 0; i < branches.Count; i++)
            {

                Console.WriteLine("\nBranch ID:{0}\nBranch Name:{1}\nBranch Address:{2}\nBranch Telno.{3}\n", branches[i].BranchID, branches[i].BranchName, branches[i].BranchAddress, branches[i].BranchTelNo);
                Console.WriteLine("************************");
            }



            /***********Add, delete, search customer in specific branch************/

            int choise;
            Console.WriteLine("\nPlease choose from the following option:\n");

        UserChoise:

            Console.WriteLine("\n1: Add Customers:\n2: Search Customer:\n3: Delete Customer:\n4: Display total no of customers in All Lidel Branches:\n5: Press enter to exit:\n");
            Console.Write("Your input is: ");
            choise = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("***************************");

            switch (choise)
            {
                case 1:
                    {
                        Console.Write("Enter the Branch name where you want to add the customer: ");
                        var BranchInput = Console.ReadLine();

                        if (BranchInput == branch1.BranchName)
                        {
                            branch1.AddCustomer();
                        }
                        else if (BranchInput == branch2.BranchName)
                        {
                            branch2.AddCustomer();
                        }
                        else if (BranchInput == branch3.BranchName)
                        {
                            branch3.AddCustomer();
                        }
                        else if (BranchInput != branch.BranchName)
                        {
                            Console.WriteLine("\nBranch doest not exist, Please enter again.\n");
                        }


                        goto UserChoise;
                    }
                case 2:
                    {
                        foreach (var bitem in branches)
                        {
                            bitem.SearchCustomer();
                            Console.Write(" in branch " +bitem.BranchName+".");
                        }
                        Console.WriteLine("***************************");
                        goto UserChoise;
                    }

                case 3:
                    {
                       foreach (var item in branches)
                        {
                            item.DeleteCustomer();
                            Console.Write(" in branch " + item.BranchName+ ".\n");
                        }
                        Console.WriteLine("***************************");
                        goto UserChoise;

                    }
                case 4:
                    {
                        //Console.WriteLine("***************************");
                        foreach (Branch bitem in branches)
                        {
                            foreach (Customer citem in bitem.customers)
                            {
                                Console.WriteLine("\nCustomer ID:{0}\nCustomer Name:{1}\nCustomer Address:{2}\nCustomer Telno.:{3}\nCustomer Email:{4}\n", citem.CustomerID, citem.CustomerName, citem.CustomerAddress, citem.CustomerTelNo, citem.CustomerEmail);
                                Console.WriteLine("***************************");
                            }
                        }
                        Console.WriteLine("***************************");
                        goto UserChoise;
                    }
                case 5:
                    {

                        Console.Write("Enter the Branch name to find its customers: ");
                        var BranchInput = Console.ReadLine();


                        foreach (Branch item in branches)
                        {
                            if (BranchInput == item.BranchName)
                            {
                                foreach (Customer citem in item.customers)
                                {

                                    {
                                        Console.WriteLine("\nCustomer ID:{0}\nCustomer Name:{1}\nCustomer Address:{2}\nCustomer Telno.:{3}\nCustomer Email:{4}\n", citem.CustomerID, citem.CustomerName, citem.CustomerAddress, citem.CustomerTelNo, citem.CustomerEmail);
                                        Console.WriteLine("***************************");
                                    }
                                }

                            }

                        }

                        goto UserChoise;
                    }

            }
        }
    }
}

Answer 1

您如何知道客户是否已经存在？ 通过电子邮件？ 按名字？ 让我们考虑客户是由CustomerName标识的（就像您在“ SearchCustomer”方法中搜索一样）。

您具有多对多的上下文（许多客户可以访问许多分支机构，许多客户可以访问许多分支机构）。

因此，如果同一位客户访问许多分支机构，则需要了解此客户。 好。

您将需要记住添加的每个客户。 就像您对分支机构一样。

就像是：

var customer = new List<Customer>()

但是您不能将其放在Main Method中，因为Branch方法无法访问它。 因此，您可以执行以下操作：

- Create a global list: public static List<Customer> Customers = new List<Customer>(); 
// initialize list for pass ArgumentNullException on LINQ methods

在AddCustomer方法中更改“ for”：

for (int i = 0; i < input; i++)
{

    Console.WriteLine("1-Customer Name:\n2-Customer Address:\n3-Customer Telno.:\n4-Customer Email:\n5-:Branch Name:\n");
    var customer = new Customer
    {
        CustomerName = Console.ReadLine()
    };
    //Search existing customer
    var existingCustomer = Customers.FirstOrDefault(c => c.CustomerName == customer.CustomerName);
    if (existingCustomer != null)
    { //existing customer encountered
        customers.Add(existingCustomer);
    }
    else
    {
        customer.CustomerID = Guid.NewGuid(); // generate new ID
        customer.CustomerAddress = Console.ReadLine();
        customer.CustomerTelNo = Console.ReadLine();
        customer.CustomerEmail = Console.ReadLine();
        customers.Add(customer);
        Customers.Add(customer); // add to global list
    }
}

但是，从对象的方法访问全局列表不是一个好主意。 您可以创建执行此过程的扩展方法或服务类。

编辑：

如果您认为可以将同一客户添加到分支机构中而不重复，则需要在分支机构客户列表中找到该客户。 只需更新代码：

var existingCustomer = Customers.FirstOrDefault(c => c.CustomerName == customer.CustomerName);
if (existingCustomer != null) //existing customer encountered ?
{ 
    // check if customer already added in the branch
    if(customers.Any(c => c.CustomerName == existingCustomer.CustomerName)){ 
        // do something
    }
    else {
        customers.Add(existingCustomer);
    }
}

Answer 2

唯一的客户可以访问多个分支机构。

多个客户可以访问一个唯一的分支。

这定义了多对多关系。

在数据库中，这将导致这种表结构：

顾客

id | someDatas
---+----------
 1 | ...
 2 | ...
 3 | ...

分支机构

id | someDatas
---+----------
 1 | ...
 2 | ...
 3 | ...

customerbranch

idcustomer | idbranch
-----------+----------
 1         | 1
 1         | 2
 2         | 3
 3         | 1
 3         | 2
 3         | 3

其中idcustomer和idbranch是表customers和branches外键

由于您没有使用数据库，因此可以通过以下方式建立Customer类和Branch类之间的关系：

class Customer
{
    public Guid CustomerID { get; set; }
    public string CustomerName { get; set; }
    public string CustomerAddress { get; set; }
    public string CustomerEmail { get; set; }
    public string CustomerTelNo { get; set; }

    public var Branches = new List<Branch>();
}

class Branch
{
    public Guid BranchID { get; set; }
    public string BranchName { get; set; }
    public string BranchAddress { get; set; }
    public string BranchTelNo { get; set; }

    public var Customers = new List<Customer>();
}

然后，在Main方法中，我将为客户和分支使用2个列表。

static void Main(string[] args)
{
    var branches = new List<Branch>();
    var customers = new List<Customer>();

    /* You can still of course hardcode some branches ... */
    branches.Add(new Branch
    {
        BranchID = Guid.NewGuid(),
        BranchName = "lidel1",
        BranchAddress = "ejbyvej 27",
        BranchTelNo = "55223366"
    });
    branches.Add(new Branch
    {
        BranchID = Guid.NewGuid(),
        BranchName = "lidel2",
        BranchAddress = "kirkevej 45",
        BranchTelNo = "77885544"
    });
    branches.Add(new Branch
    {
        BranchID = Guid.NewGuid(),
        BranchName = "lidel3",
        BranchAddress = "kirkevej 12",
        BranchTelNo = "553366611"
    });

    /* ... and some customers */

    customers.Add(new Branch
    {
        CustomerID = Guid.NewGuid(),
        CustomerName = "John Smith",
        CustomerAddress = "somewhere",
        CustomerTelNo = "0123456789",
        CustomerEmail = "john.smith@example.com"
    });
    customers.Add(new Branch
    {
        CustomerID = Guid.NewGuid(),
        CustomerName = "Jane Doe",
        CustomerAddress = "Elsewhere",
        CustomerTelNo = "9876543210",
        CustomerEmail = "jane.doe@example.com"
    });
    customers.Add(new Branch
    {
        CustomerID = Guid.NewGuid(),
        CustomerName = "Foo Bar",
        CustomerAddress = "anywhere",
        CustomerTelNo = "4242424242",
        CustomerEmail = "foo.bar@example.com"
    });
}

现在有一些分支机构和一些客户，但是它们之间还没有关系。

您可以在branche类中构建一个方法来添加现有客户。

class Branch
{
    //Some properties...

    //The customer already exists and is used as parameter
    public void AddCustomer(Customer customer)
    {
        this.Customers.Add(customer); //the reference to the customer is added to the list.

        /*
         * Now, since we're in a Mant-To-Many relation,
         * we have to add the current branch to the newly added customer
         */

        customer.Branches.Add(this);
    }
}

我们可以对Customer类执行相同的操作，但这不是必需的：

class Customer
{
    //Some properties...

    //The branch already exists and is used as parameter
    public void AddBranch(Branch branch)
    {
        this.Branches.Add(branch); //the reference to the branch is added to the list.

        /*
         * Now, since we're in a Mant-To-Many relation,
         * we have to add the current customer to the newly added branch
         */

        branch.Customers.Add(this);
    }
}

当然，当您在客户对象中添加了一个分支，并且在该分支中添加了当前客户时，请不要执行branch.AddCustomers(this); 否则，将存在一个无限循环，因为一个方法将调用另一个方法。

现在，让我们将第二个客户Jane Doe添加到第三个的lidel3分支中。

static void Main(string[] args)
{
    // Some code already written ...

    branches[2].AddCustomer(customers[1]);
}

我们可以向客户John Smith添加分支Lidel2的方法相同

static void Main(string[] args)
{
    // Some code already written ...

    customers[0].AddBranch(branches[1]);
}

现在，写代码的左边就是让用户添加新客户，新分支并在它们之间建立关系，这是您的工作。

额外：

为了避免goto ，我将使用以下逻辑：

int choice = 1; //default arbitrary value to make sure the while condition is true

while (choice >= 1 && choice <= 4) //condition is true if user input is 1 2 3 or 4
{
    Console.WriteLine("\n1: Add Customers:\n2: Search Customer:\n3: Delete Customer:\n4: Display total no of customers in All Lidel Branches:\n5: Press enter to exit:\n");
    Console.Write("Your input is: ");
    choice = Convert.ToInt32(Console.ReadLine());
    Console.WriteLine("***************************");

    switch (choice)
    {
        case 1:
            //some code to handle the case 1
        break; //use break to leave the switch case instead of goto

        case 2:
            //some code to handle the case 2
        break;
        //And so on ...
    }
} //When while condition is false, the loop is exited