Question

我试图从用户那里获得用户输入，直到用户没有输入任何内容（所以按下回车键）但它似乎没有正常工作。用户应该能够添加他们想要的数量，并且一旦他们点击输入键而没有输入数字就应该显示它们。

代码：

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

namespace Lab2
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> numbersInput = new List<string>();

            Console.WriteLine("Please enter an integer");
            string input = Console.ReadLine();
            numbersInput.Add(input);


            while (input != "")
            {
                Console.WriteLine("Please enter another integer: ");
               input = Console.ReadLine();
            }

            if (input == "")
            {
                Console.WriteLine("The number you have entered is: " + " " + input);
                numbersInput.Add(input);
                foreach (string value in numbersInput)
                {
                    Console.WriteLine("The number that was added to the list is : " + " " + value);
                }
                Console.ReadLine();
            }
        }
    }
}

Answer 1

除了空字符串外，您没有向numbersInput列表中添加任何内容。

 if (input == "") // Why do anything with input if you enter this block?
 {
     Console.WriteLine("The number you have entered is: " + " " + input);
     numbersInput.Add(input);
     foreach (string value in numbersInput)

numbersInput.Add(input)需要在while块中。

试试这个

while (input != "")
{
    Console.WriteLine("Please enter another integer: ");
    input = Console.ReadLine();
    numbersInput.Add(input);
}

if (input == "")
{
    foreach (string value in numbersInput)
    {
        Console.WriteLine("The number that was added to the list is : " + " " + value);
    }
    Console.ReadLine();
}

编辑：用于求和

更改您的列表声明。

List<int> numbersInput = new List<int>();

然后解析数字并将它们添加到列表中。如果解析失败，则需要处理错误。

while (input != "")
{
    Console.WriteLine("Please enter another integer: ");
    input = Console.ReadLine();
    int value;
    if(!int.TryParse(input, out value))
    {
       // Error
    }
    else
    {
       numbersInput.Add(value);
    }
}

然后你的列表不再是字符串，所以改变foreach

int sum = 0;
foreach (int value in numbersInput)
{
    sum += value;
    Console.WriteLine("The number that was added to the list is : " + " " + value.ToString());
}

Answer 2

尝试将input != ""替换为!String.IsNullOrEmpty(input) 和input==""与StringIsNullOrEmpty(input)。

喜欢这个：

＆＃13;

 List<string> numbersInput = new List<string>();

        Console.WriteLine("Please enter an integer");
        string input = Console.ReadLine();

        while (!String.IsNullOrEmpty(input))
        {

            Console.WriteLine("Please enter another integer: ");
           input = Console.ReadLine();

        }


        if (String.IsNullOrEmpty(input))
        {
            Console.WriteLine("The number you have entered is: " + " " + input);
            numbersInput.Add(input);
            foreach (string value in numbersInput)
            {
                Console.WriteLine("The number that was added to the list is : " + " " + value);
            }
            Console.ReadLine();
        }

＆＃13;

Answer 3

不要将字符串与＆＃34;＆＃34;进行比较，而是使用string.IsNullOrEmpty（）或string.IsNullOrWhitespace（）（假设您的目标是.NET Framework 2.0或更高版本。）
您有不必要的代码（final if语句），它不提供任何值。

除此之外，您的代码需要重新构建。

这可能是您正在寻找的：

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

namespace Lab2
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> numbersInput = new List<string>();

            Console.WriteLine("Please enter an integer: ");
            string input = Console.ReadLine();

            while (!string.IsNullOrEmpty(input))
            {
                numbersInput.Add(input);
                Console.WriteLine("Please enter another integer: ");
                input = Console.ReadLine();
            }

            if (numbersInput.Count > 0)
            {
                Console.WriteLine("You have entered " + numbersInput.Count + " numbers, they were: ");  
                foreach (var input in numbersInput)
                {
                    Console.WriteLine("\t" + input);
                }
            }
            else
            {
                Console.WriteLine("You have entered 0 numbers.");  
            }

        }
    }
}

HTH

Answer 4

您没有将numberInput添加到列表中：

        static void Main(string[] args)
    {

        String input;
        Int32 n_In, i = 1;
        List<Int32> user_Inputs = new List<int>();

        while ((input = Console.ReadLine()).Length > 0)
            if (int.TryParse(input, out n_In)) user_Inputs.Add(n_In);

        Console.WriteLine("Numbers entered: ");
        if (user_Inputs.Count == 0) return;

        foreach (Int32 n in user_Inputs)
            Console.WriteLine("Number" + i++ + ": " + n);

        Console.ReadKey();
    }

Answer 5

非常短的版本，不会添加您的个人逻辑，但应该展示这个想法：

using System;
using System.Collections.Generic;

namespace Test
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            List<string> listofstrings = new List<string> ();
            string input = null;

            while ((input = Console.ReadLine ()) != string.Empty) {
                listofstrings.Add (input);
            }
        }
    }
}

将多个用户输入添加到List c＃

5 个答案: