如何添加到foreach循环中的现有数组/可枚举集合

var originalList = new List<int> { 1, 2, 3 };
var tempList = new List<int>();

foreach (var item in originalList)
{
    if (item % 2 == 0) // 假设我们只想添加偶数
    {
        tempList.Add(item * 2);
    }
}

originalList.AddRange(tempList);

var originalList = new List<int> { 1, 2, 3 };

for (int i = 0; i < originalList.Count; i++)
{
    if (originalList[i] % 2 == 0)
    {
        originalList.Add(originalList[i] * 2);
        i--; // 调整索引以重新检查新添加的元素
    }
}

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        var numbers = new List<int> { 1, 2, 3, 4, 5 };
        var newNumbers = new List<int>();

        foreach (var number in numbers)
        {
            Console.WriteLine(number);
            if (number % 2 == 0)
            {
                newNumbers.Add(number * 2);
            }
        }

        numbers.AddRange(newNumbers);

        Console.WriteLine("Updated list:");
        foreach (var number in numbers)
        {
            Console.WriteLine(number);
        }
    }
}