瞭解C#檔案上傳類，檔案流，位元組數組等知識

using System;using System.IO;using System.Web;using System.Web.UI.WebControls;namespace DotNet.Utilities{    /// <summary>    /// 檔案上傳類    /// </summary>    public class FileUp    {        public FileUp()        { }        /// <summary>        /// 轉換為位元組數組        /// </summary>        /// <param name="filename">檔案名稱</param>        /// <returns>位元組數組</returns>        public byte[] GetBinaryFile(string filename)        {            if (File.Exists(filename))            {                FileStream Fsm = null;                try                {                    Fsm = File.OpenRead(filename);                    return this.ConvertStreamToByteBuffer(Fsm);                }                catch                {                    return new byte[0];                }                finally                {                    Fsm.Close();                }            }            else            {                return new byte[0];            }        }        /// <summary>        /// 流轉化為位元組數組        /// </summary>        /// <param name="theStream">流</param>        /// <returns>位元組數組</returns>        public byte[] ConvertStreamToByteBuffer(System.IO.Stream theStream)        {            int bi;            MemoryStream tempStream = new System.IO.MemoryStream();            try            {                while ((bi = theStream.ReadByte()) != -1)                {                    tempStream.WriteByte(((byte)bi));                }                return tempStream.ToArray();            }            catch            {                return new byte[0];            }            finally            {                tempStream.Close();            }        }        /// <summary>        /// 上傳檔案        /// </summary>        /// <param name="PosPhotoUpload">控制項</param>        /// <param name="saveFileName">儲存的檔案名稱</param>        /// <param name="imagePath">儲存的檔案路徑</param>        public string FileSc(FileUpload PosPhotoUpload, string saveFileName, string imagePath)        {            string state = "";            if (PosPhotoUpload.HasFile)            {                if (PosPhotoUpload.PostedFile.ContentLength / 1024 < 10240)                {                    string MimeType = PosPhotoUpload.PostedFile.ContentType;                    if (String.Equals(MimeType, "image/gif") || String.Equals(MimeType, "image/pjpeg"))                    {                        string extFileString = System.IO.Path.GetExtension(PosPhotoUpload.PostedFile.FileName);                        PosPhotoUpload.PostedFile.SaveAs(HttpContext.Current.Server.MapPath(imagePath));                    }                    else                    {                        state = "上傳檔案類型不正確";                    }                }                else                {                    state = "上傳檔案不能大於10M";                }            }            else            {                state = "沒有上傳檔案";            }            return state;        }        /// <summary>        /// 上傳檔案        /// </summary>        /// <param name="binData">位元組數組</param>        /// <param name="fileName">檔案名稱</param>        /// <param name="fileType">檔案類型</param>        //-------------------調用----------------------        //byte[] by = GetBinaryFile("E:\\Hello.txt");        //this.SaveFile(by,"Hello",".txt");        //---------------------------------------------        public void SaveFile(byte[] binData, string fileName, string fileType)        {            FileStream fileStream = null;            MemoryStream m = new MemoryStream(binData);            try            {                string savePath = HttpContext.Current.Server.MapPath("~/File/");                if (!Directory.Exists(savePath))                {                    Directory.CreateDirectory(savePath);                }                string File = savePath + fileName + fileType;                fileStream = new FileStream(File, FileMode.Create);                m.WriteTo(fileStream);            }            finally            {                m.Close();                fileStream.Close();            }        }    }}