如何在.NET中删除txt文件开头的n个字符？

using System;
using System.IO;

class Program
{
    static void Main()
    {
        string filePath = "path/to/your/file.txt";
        int numOfCharsToDelete = 5;

        // 读取txt文件内容
        using (StreamReader sr = new StreamReader(filePath))
        {
            string line;
            string modifiedContent = "";
            while ((line = sr.ReadLine()) != null)
            {
                // 删除开头的n个字符
                if (line.Length > numOfCharsToDelete)
                {
                    line = line.Substring(numOfCharsToDelete);
                }
                else
                {
                    line = ""; // 如果字符数小于或等于n，则删除整行
                }
                modifiedContent += line + Environment.NewLine;
            }

            // 写入修改后的内容到txt文件
            using (StreamWriter sw = new StreamWriter(filePath))
            {
                sw.Write(modifiedContent);
            }
        }
    }
}