c#对文件流的操作

 //写文件
        private static bool WriteFile(byte[] byData, string path)
        {
            try
            {
                string filepath = System.Web.HttpContext.Current.Server.MapPath(path);
                if (File.Exists(path))
                    File.Delete(path);

                 System.IO.FileStream fs = System.IO.File.Create(path);
                 fs.Write(byData, 0, byData.Length);
                 fs.Flush();
                 fs.Close();                   
                 return true;

            }
            catch (Exception ex)
            {
                return false;
            }
            finally
            {

            }
        }
        //生成一个文件
        public static bool CreateFile(string filecontent, string path)
        {
            try
            {
                string filePath = System.Web.HttpContext.Current.Server.MapPath(path);
                if (File.Exists(filePath))
                    File.Delete(filePath);
                else
                {
                    System.IO.FileStream fs = System.IO.File.Create(path);
                    byte[] byContent = System.Text.Encoding.GetEncoding("gb2312").GetBytes(filecontent);
                    fs.Write(byContent, 0, byContent.Length);
                    fs.Flush();
                    fs.Close();
                }
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
            finally
            {
            }
        }
        //读入文件
        public static string WriteFile(string path)
        {
            try
            {
                string filepath = System.Web.HttpContext.Current.Server.MapPath(path);
                if (File.Exists(filepath))
                    return "false";
                else
                {
                    string fileread = System.IO.File.ReadAllText(filepath, System.Text.Encoding.GetEncoding("gb2312"));
                    return fileread;
                }
            }
            catch (Exception ex)
            {
                return "false";
            }
            finally
            {

            }
        }
        //向文件中增加内容
        public static bool UpdateFile(string filecontent, string path)
        {
            try
            {
                string filePath = System.Web.HttpContext.Current.Server.MapPath(path);
                if (!File.Exists(filePath))
                {
                    System.IO.FileStream fs = System.IO.File.Create(filePath);
                    byte[] byContent = System.Text.Encoding.GetEncoding("gb2312").GetBytes(filecontent);
                    fs.Write(byContent, 0, byContent.Length);
                    fs.Flush();
                    fs.Close();
                }
                System.IO.FileStream files = new System.IO.FileStream(filePath, FileMode.Open, FileAccess.ReadWrite);
                StreamReader sReader = new StreamReader(files, System.Text.Encoding.Default);
                string oldstr = sReader.ReadToEnd();
                oldstr += filecontent;
                //把新的内容重新写入
                StreamWriter sWriter = new StreamWriter(files, System.Text.Encoding.Default);
                sWriter.Write(oldstr);
                sWriter.Flush();
                sWriter.Close();
                sReader.Close();
                files.Close();
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }
        //删除文件
        public static bool Delete(string path)
        {
            try
            {
                string filePath = System.Web.HttpContext.Current.Server.MapPath(path);
                if (File.Exists(path))
                    File.Delete(filePath);
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
            finally { }
        }
        //创建文件夹
        public static bool CreateFolder(string FolderName)
        {
            try
            {
                if (FolderName.Trim().Length > 0)
                {
                    string folderPath = System.Web.HttpContext.Current.Server.MapPath(FolderName);
                    if (!System.IO.Directory.Exists(folderPath))
                    {
                        System.IO.Directory.CreateDirectory(folderPath);
                        return true;
                    }
                    else
                        return false;
                }
                else
                    return false;
            }
            catch (Exception ex)
            {
                return false;
            }
            finally { }           
        }
        //删除整个文件夹以及整个子文件夹和文件
        public static bool DeleteDirctory(string folderName)
        {
            try
            {
                string filePath = System.Web.HttpContext.Current.Server.MapPath(folderName);
                if (System.IO.Directory.Exists(filePath))
                {
                    System.IO.Directory.Delete(filePath);
                    return true;
                }
                else
                    return false;

            }
            catch (Exception ex)
            {
                return false;
            }
            finally
            {
            }
        }
        //遍历一个目录下的全部目录
        public static DataTable GetDir(string foldername)
        {
            try
            {
                DataTable dt = new DataTable();
                dt.Columns.Add("name", typeof(string));
                dt.Columns.Add("fullName", typeof(string));
                string filePath = System.Web.HttpContext.Current.Server.MapPath(foldername);
                System.IO.DirectoryInfo dir = new DirectoryInfo(filePath);
                foreach (System.IO.FileInfo dchild in dir.GetFiles("*"))
                {
                    DataRow dr = dt.NewRow();
                    dr["name"] = dchild.Name; //目录名
                    dr["fullname"] = dchild.FullName;
                    dt.Rows.Add(dr);
                }
                return dt;
            }
            catch (Exception ex)
            {
                return null;
            }
            finally { }
        }