C#：文本文件讀寫操作 FileHelper

    public class FileHelper
    {
        /// <summary>
        /// 獲取指定路徑下所有文件
        /// </summary>        
        public static List<string> GetFiles(string path)
        {            
            //using System.IO;
            if (!Directory.Exists(path))  //路徑不存在
                return null;           
            List<string> result = new List<string>();            
            DirectoryInfo dir = new DirectoryInfo(path);            
            DirectoryInfo[] subfolder = dir.GetDirectories();
            if (subfolder != null&&subfolder.Length>0)
            {
                foreach(DirectoryInfo item in subfolder)
                {                    
                    List<string> subFiles = GetFiles(item.FullName);  //FullName:完整路徑
                    if (subFiles != null && subFiles.Count > 0)
                        result.AddRange(subFiles);
                }
            }
            FileInfo[] files = dir.GetFiles();
            if(files!=null)
            {
                foreach(FileInfo file in files)
                {
                    result.Add(file.FullName);
                }
            }
            return result;
        }

        /// <summary>
        /// 獲取指定文件內容
        /// 注：這里適用於讀取文本類型文件
        /// </summary>
        public static List<string> GetTxtFileContent(string fileName)
        {
            if (!File.Exists(fileName)) //文件不存在
                return null;
            FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
            StreamReader reader = new StreamReader(fs, Encoding.Default);
            List<string> result = new List<string>();
            string line = "";
            while((line=reader.ReadLine())!=null)
            {
                result.Add(line);
            }
            reader.Close();
            fs.Close();
            return result;            
        } 

        /// <summary>
        /// 刪除指定文件
        /// </summary>        
        public static void DeleteFile(string fileName)
        {
            File.Delete(fileName);
        }

        /// <summary>
        /// 創建文件
        /// </summary>
        /// <param name="path">文件全路徑</param>
        /// <param name="content">寫入內容</param>
        public static void CreateFile(string fileName,List<string> content=null)
        {
            if(!File.Exists(fileName))
            {
                FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write);
                if (content != null && content.Count > 0)
                {
                    StreamWriter sw = new StreamWriter(fs);
                    foreach (string line in content)
                    {
                        sw.WriteLine(line);
                    }
                    sw.Close();
                }
                fs.Close();
            }            
        }
        
    }