获取文本文件C#中当前行上方的2行

using System;
using System.Collections.Generic;
using System.IO;

public class Program
{
    public static void Main()
    {
        string filePath = "example.txt"; // 替换为实际的文件路径

        // 获取当前行的行号
        int currentLineNumber = 5; // 替换为实际的当前行号

        List<string> lines = new List<string>();

        // 逐行读取文件内容
        using (StreamReader sr = new StreamReader(filePath))
        {
            string line;
            int lineNumber = 0;

            while ((line = sr.ReadLine()) != null)
            {
                lineNumber++;

                // 保存每一行的内容
                lines.Add(line);

                // 当读取到当前行时
                if (lineNumber == currentLineNumber)
                {
                    // 获取当前行上方的2行内容
                    int startLineNumber = currentLineNumber - 2;
                    int endLineNumber = currentLineNumber - 1;

                    if (startLineNumber >= 0)
                    {
                        for (int i = startLineNumber; i <= endLineNumber; i++)
                        {
                            Console.WriteLine(lines[i]);
                        }
                    }
                    else
                    {
                        Console.WriteLine("当前行上方的行数不足2行。");
                    }

                    break;
                }
            }
        }
    }
}