Question

首先，我对编码的大部分经验是通过python，因此我使用了global

我有一个列表，我希望能够搜索列表并查找x长度的所有单词。我的主要问题是不知道如何从事件监听器内部调用函数。

因此myList在我的函数functionOne中生成，我想在functionTwo中使用此列表，最后我想在buttonOne时调用它点击。 E.g buttonOne_Click ....

这是我到目前为止functionOne

的内容

public List<string> noDup(List<string> myList)
        {
            var convert = myList.ConvertAll(i => i.ToLower());
            List<string> remove = convertLower.Distinct().ToList();
            return remove;
        }

functionTwo

    public List<string> length(List<string> myList)
    {
        int i = int.Parse(lengthSearch.Text);
        List<string> temp = new List<string>();

        foreach(string item in myList)
        {
            if(item.Length == i)
            {
                temp.Add(item);
            }
        }
        searchResult.Text = string.Join(",", temp);
    }

最后是我的事件监听器

private void button_Click(object sender, EventArgs e)
        {
            length(remove);
        }

注意：remove是我尝试使用的列表

但此代码没有输出，因为我收到错误消息说在此上下文中不存在删除操作，我不确定如何创建此列表global

Answer 1

我们在这里是如何在win form c＃应用程序中实现这一目标的总体思路。

using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        private List<string> _remove;

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            length(_remove);
        }

        public List<string> noDup(List<string> myList)
        {
            var convert = myList.ConvertAll(i => i.ToLower());
            _remove = convertLower.Distinct().ToList();

        }

        public List<string> length(List<string> myList)
        {
            int i = int.Parse(lengthSearch.Text);
            List<string> temp = new List<string>();

            foreach (string item in myList)
            {
                if (item.Length == i)
                {
                    temp.Add(item);
                }
            }
            searchResult.Text = string.Join(",", temp);
        }
    }
}

请注意，由于我刚刚使用了您的代码，因此无法构建。例如，length方法应该返回List<string>但不会返回_remove。您可能希望更改传入的列表然后返回它，或者改变类级变量button1_Click。

无论哪种方式，事件处理程序_remove都需要使用类级别变量（例如我添加的#include <iostream> using namespace std; int main() { double type_ticket, num_tickets, price1, price2, price3, total_price, decision; cout << "Welcome to the ticket kiosk."; cout << "\n"; cout << "\n"; cout << "1. VVIP - RM 200"; cout << "\n"; cout << "2. VIP - RM 150"; cout << "\n"; cout << "3. Normal - RM 100" << endl; cout << "\n"; do { cout << "Please select the category of ticket you would like to purchase: "; cin >> type_ticket; cout << "\n"; if (type_ticket == 1) { cout << "How many would you like: "; cin >> num_tickets; cout << "\n"; price1 = num_tickets * 200; cout << "The price is: RM " << price1 << endl; cout << "\n"; cout << "\n"; cout << "1. YES" << endl; cout << "2. NO" << endl; cout << "\n"; cout << "Would you like to continue purchasing more tickets: "; cin >> decision; cout << "\n"; } else if (type_ticket == 2) { cout << "How many would you like: "; cin >> num_tickets; cout << "\n"; price2 = num_tickets * 150; cout << "The price is: RM " << price2 << endl; cout << "\n"; cout << "\n"; cout << "1. YES" << endl; cout << "2. NO" << endl; cout << "\n"; cout << "Would you like to continue purchasing more tickets: "; cin >> decision; cout << "\n"; } else if (type_ticket == 3) { cout << "How many would you like: "; cin >> num_tickets; cout << "\n"; price3 = num_tickets * 100; cout << "The price is: RM " << price3 << endl; cout << "\n"; cout << "\n"; cout << "1. YES" << endl; cout << "2. NO" << endl; cout << "\n"; cout << "Would you like to continue purchasing more tickets: "; cin >> decision; cout << "\n"; } else { cout << "You have entered an invalid input, please try again. " << endl; cout << "\n"; } } while (decision == 1); total_price = price1 + price2 + price3; cout << "The grand total is: RM " << total_price << endl; cout << "\n"; cout << "Thank you for using this service today, we hope you enjoy the show." << endl; cout << "\n"; }）或调用将返回列表的方法（如另一个{ {3}}由Zbigniew撰写。）

Answer 2

将所有函数放在同一个类中，并在列表实例上使用noDup。

    public List<string> noDup(List<string> myList)
        {
            var convert = myList.ConvertAll(i => i.ToLower());
            List<string> remove = convertLower.Distinct().ToList();
            return remove;
        }

    public void length(List<string> myList)
    {
        int i = int.Parse(lengthSearch.Text);
        List<string> temp = new List<string>();

        foreach(string item in myList)
        {
            if(item.Length == i)
            {
                temp.Add(item);
            }
        }
        searchResult.Text = string.Join(",", temp);
    }

        private void button_Click(object sender, EventArgs e)
        {   
            var remove = noDup(yourInputList);
            length(remove);
        }

如何在c＃中创建一个“global”列表？

2 个答案: