删除类的函数

本文关键字:函数 删除 | 更新日期: 2023-09-27 18:29:43

我的删除函数有问题。除了删除功能外,我什么都能用。

如有任何帮助,我们将不胜感激。我试着更改了一下,但仍然没有删除。我不知道我的remove函数有什么问题。

public class Person
{
    private string name;
    private string phoneNumber;
    public string Name
    {
        set { name = value; }
        get { return name; }
    }
    public string PhoneNumber
    {
        set { phoneNumber = value; }
        get { return phoneNumber; }
    }
    public void PrintInfo()
    {
        Console.WriteLine();
        Console.WriteLine(" Name: {0}", name);
        Console.WriteLine(" Phone Number: {0}", phoneNumber);
        Console.WriteLine();
    }
    public void SaveASCII(ref StreamWriter output)
    {
        output.WriteLine(name);
        output.WriteLine(phoneNumber);
    }
    public void LoadASCII(ref StreamReader input)
    {
        name = input.ReadLine();
        phoneNumber = input.ReadLine();
    }
}

public class membershipList
{
    public Person[] ML = null;
    public void AddMember(Person p)
    {
        if (ML == null)
        {
            ML = new Person[1];
            ML[0] = p;
        }
        else
        {
            Person[] temp = ML;
            ML = new Person[temp.Length + 1];
            for (int i = 0; i < temp.Length; ++i)
            {
                ML[i] = new Person();
                ML[i] = temp[i];
            }
            ML[temp.Length] = new Person();
            ML[temp.Length] = p;
            temp = null;
        }
    }
    public void DeleteMember(string p)
    {
        if (ML != null)
        {
            foreach (Person pers in ML)
            {
                if (pers.Name.ToLower().CompareTo(p.ToLower()) == 0)
                {
                  pers.Remove();
                  break;
                }
            }
        }
        else Console.WriteLine("Then list is empty.");
    }

                //   {
                //      int memberIndex = Array.FindIndex(ML, p => p.Name == name);
                //      if (memberIndex == -1)
                //    {
                //        Console.WriteLine(name + " had not been added before.");
                //      return;
                //   }
               // else
               // {
                //    List<Person> tmp = new List<Person>(ML);
               //     tmp.RemoveAt(memberIndex);
               //     ML = tmp.ToArray();
               // }
       // }
  //  }

    public void PrintAll()
    {
        if (ML != null)
            foreach (Person pers in ML)
                pers.PrintInfo();
        else Console.WriteLine("Then list is empty");
    }
    public void Search(string p)
    {
        if (ML != null)
        {
            foreach (Person pers in ML)
            {
                if (pers.Name.ToLower().CompareTo(p.ToLower()) == 0)
                {
                    Console.WriteLine("1 Record Found:");
                    pers.PrintInfo();
                    break;
                }
            }
        }
        else Console.WriteLine("Then list is empty.");
    }
    public void ReadASCIIFile()
    {
        StreamReader input = new StreamReader("memberlist.dat"); ;
        try
        {
            int num = Convert.ToInt32(input.ReadLine());
            ML = new Person[num];
            for (int i = 0; i < num; ++i)
            {
                ML[i] = new Person();
                ML[i].LoadASCII(ref input);
            }
            input.Close();
        }
        catch (FormatException e)
        {
            Console.WriteLine(e.Message);
            input.Close();
        }

    }
    public void SaveASCIIFile()
    {
        StreamWriter output = new StreamWriter("memberlist.dat");
        output.WriteLine(ML.Length);
        foreach (Person pers in ML)
        {
            pers.SaveASCII(ref output);
        }
        output.Close();

    }
}

class Program
{
    static void Main(string[] args)
    {
        membershipList ML = new membershipList();
        ML.ReadASCIIFile();
        string option;
        do
        {
            // Console.Clear();
            Console.WriteLine();
            Console.WriteLine();
            Console.WriteLine("MemberShip List MENU");
            Console.WriteLine();
            Console.WriteLine("     a. Add");
            Console.WriteLine("     b. Seach");
            Console.WriteLine("     c. Delete");
            Console.WriteLine("     d. Print All");
            Console.WriteLine("     e. Exit");
            Console.WriteLine();
            Console.Write("option: ");
            option = Console.ReadLine().ToLower();
            switch (option)
            {
                case "a":
                    Person np = new Person();
                    Console.Write("Enter Name: ");
                    np.Name = Console.ReadLine();
                    Console.Write("Enter PhoneNumber: ");
                    np.PhoneNumber = Console.ReadLine();
                    ML.AddMember(np);
                    break;
                case "b":
                    Console.Write("Enter Name: ");
                    string name = Console.ReadLine();
                    ML.Search(name);
                    break;
                case "c":
                    Console.Write("Enter Name to be Deleted:");
                    string pers = Console.ReadLine();
                    ML.DeleteMember(pers);
                    break;
                case "d":
                    ML.PrintAll();
                    break;
                case "e":
                    ML.SaveASCIIFile();
                    Console.WriteLine("BYE...... ");
                    break;
                default:
                    Console.WriteLine("Invalid Option");
                    break;
            }

        } while (option.ToLower() != "d");
    }
}

删除类的函数

我看到两件事:

  1. 如果要在列表中添加和删除项,请使用List<Person>而不是数组。现在,您需要将数组复制到一个临时列表中,删除该项,然后再复制回一个数组
  2. 您的Delete功能可以只是:

    if (ML != null)
    {
        Person pers = ML.FirstOrDefault(x => x.Name.ToLower() == p.ToLower());
        if(pers != null)
        {
              ML.Remove(pers);
              break;
        }
    }
    

您的问题是:

foreach (Person pers in ML)
{
    if (pers.Name.ToLower().CompareTo(p.ToLower()) == 0)
    {
        pers.Remove();
        break;
    }
}

您正在从正在迭代的集合中移除,这会抛出循环的迭代器。

无论哪种方法都可以反向循环通过集合,因此移除不会丢弃循环的迭代器。

创建第二个列表,其中包含要保留的值。所以,从本质上讲,你会做相反的事情;与其删除,不如不将其添加到保留列表中。

您在数组上循环,然后对人员调用remove。关于for each循环的一点是,它使用迭代器,在for each过程中无法修改迭代器。但即使可以,也没那么简单,因为你不能简单地从数组中移除。您可以从泛型List或ListArray中执行此操作,但不能从数组中执行。要遵循您已经遵循的模式(假设您需要使用数组并调整它们的大小),您需要创建一个临时数组,并将ML数组中的所有元素复制到新数组中,减去已删除的成员。

检查我的语法,因为我没有测试这段代码,但你应该知道。

public void DeleteMember(string p)
    {
        if (ML != null)
        {
            Person[] tempList = new Person[ML.Length - 1];
            bool deletedAPerson = false;
            int i = 0;
            foreach (Person pers in ML)
            {
                if (pers.Name.ToLower().CompareTo(p.ToLower()) == 0)
                {
                   deletedAPerson = true;
                   continue; //skip over this person and do not copy over to the new Array
                }
                if(i < pers.Length) //if no person was found, prevent index out of bounds exception
                    tempList[i++] = pers;
            }
            if(deletedAPerson)
               ML = tempList;
        }
        else Console.WriteLine("Then list is empty.");
    }