如何从C＃中的数组列表中删除元素 [英] How to remove elements from array list in C#

问题描述

从arraylist中删除元素后，它不会影响到arraylist。

在检索arraylist元素时，再次显示删除元素。

如何重新解决这个问题？



我的尝试：

After removing elements from arraylist,its not effecting to arraylist.
when retrieving the arraylist elements ,then again its showing the deleting elements.
How to reslove this problem?

What I have tried:

public class BaseEmployee
    {
        public int Id;
        public string Name;
    }

    public class Employee : BaseEmployee
    {
        public string Address;



        public Object Add()
        {

            Employee employeeDetail = new Employee();
            Console.Write("Employee Id:");
            employeeDetail.Id = int.Parse(Console.ReadLine());

            Console.Write("Employee Name:");
            employeeDetail.Name = Console.ReadLine();
            Console.Write("Employee Address:");
            employeeDetail.Address = Console.ReadLine();
            return employeeDetail;

        }

        static void Main(string[] args)
        {

            ArrayList arraylist = new ArrayList();
          


            Employee employeeDetails = new Employee();

            bool p = true;

            while (p)
            {

                Console.WriteLine("Employee Record Management System\n");
                Console.WriteLine("\n1)Add");
                Console.WriteLine("\n2)Edit");
                Console.WriteLine("\n3)Delete");
                Console.WriteLine("\n4)Dispaly");
                Console.WriteLine("\n5)Exit");
                Console.Write("\n Select opertaion:");
                int Option = int.Parse(Console.ReadLine());

                switch (Option)
                {
                    case 1:
                        arraylist.Add(employeeDetails.Add());

                        break;


                    case 4:
                        foreach (Object obj in arraylist)
                        {

                            Employee emp = obj as Employee;
                            Console.Write("{0}\t\t{1}\t\t{2}", emp.Id, emp.Name, emp.Address);
                            Console.Write("\n");
                            //Console.WriteLine(obj);
                        }


                        break;
            case 3:Console.Write("Enter  Employee Id:");
                        int EId = int.Parse(Console.ReadLine());
                        foreach(Object obj in arraylist)
                        {
                            Employee emp = obj as Employee;
                            if(EId==emp.Id)
                            {

                                arraylist.Remove(emp.Id);
                                arraylist.Remove(emp.Name);
                                arraylist.Remove(emp.Address);
                               

                            }
                        }

                          break;



                }

            }
        }

    }
}

推荐答案

你应该删除对象而不是对象的属性：

You should remove the object not the properties of the object :

...
          arraylist.Remove(emp);
...

我建​​议您使用List< Employee>而不是ArrayList。

你将避免使用Object（每次都使用它）并且你的代码将更容易阅读。

此外你将能够使用方法RemoveAll：



arraylist.RemoveAll（emp => emp.Id == EId）;



我重写了你的代码片段，所以你可以评估我的建议：

I suggest you to use List<Employee> instead of ArrayList.
You'll avoid using Object (casting it every time) and your code will be easier to read.
Moreover you'll be able to use the method RemoveAll:

arraylist.RemoveAll(emp => emp.Id == EId);

I rewritten your code fragment, so you can evaluate my advice:

public class BaseEmployee
    {
        public int Id;
        public string Name;
    }
 
    public class Employee : BaseEmployee
    {
        public string Address;

        public static Employee Add()
        {
 
            var employeeDetail = new Employee();
            Console.Write("Employee Id:");
            employeeDetail.Id = int.Parse(Console.ReadLine());
 
            Console.Write("Employee Name:");
            employeeDetail.Name = Console.ReadLine();
            Console.Write("Employee Address:");
            employeeDetail.Address = Console.ReadLine();
            return employeeDetail;
 
        }
 
        static void Main(string[] args)
        {

            var arraylist = new List<Employee>();
          
            //Employee employeeDetails = new Employee();
 
            bool p = true;
 
            while (p)
            {
 
                Console.WriteLine("Employee Record Management System\n");
                Console.WriteLine("\n1)Add");
                Console.WriteLine("\n2)Edit");
                Console.WriteLine("\n3)Delete");
                Console.WriteLine("\n4)Dispaly");
                Console.WriteLine("\n5)Exit");
                Console.Write("\n Select operation:");
                int Option = int.Parse(Console.ReadLine());
 
                switch (Option)
                {
                    case 1:
                        arraylist.Add(Employee.Add());
 
                        break;
 

                    case 4:
                        foreach (Employee emp in arraylist)
                        {
 
                            //Employee emp = obj as Employee;
                            Console.Write("{0}\t\t{1}\t\t{2}", emp.Id, emp.Name, emp.Address);
                            Console.Write("\n");
                            //Console.WriteLine(obj);
                        }
 

                        break;
                    case 3:
                        Console.Write("Enter  Employee Id:");
                        int EId = int.Parse(Console.ReadLine());
                        
                        arraylist.RemoveAll(emp => emp.Id == EId);
                        
                        break;
                }
 
            }
        }
 
    }

再见

Bye

如果您要更改列表，则无法在 foreach 循环内执行此操作。 />


我的建议是使用linq找到它，如果找到则删除它。

If you're going to be changing the list, you can't do it inside a foreach loop.

My advice is to use linq to find it, and then remove it if found.

var found = arraylist.Where(x=>x.Id == EId).FirstOrDefault();
if (found != null)
{
    arraylist.Remove(found);
}

这篇关于如何从C＃中的数组列表中删除元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！