C# http 斷點續傳

 

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.IO;using System.Net;namespace XcDownLoadFile{    public class DownLoadFile    {        ///        /// 下載檔案方法        ///        /// 檔案儲存路徑和檔案名稱        /// 返回伺服器檔案名稱        ///        public bool DeownloadFile(string strFileName, string file)        {            bool flag = false;            //開啟上次下載的檔案            long SPosition = 0;            //執行個體化流對象            FileStream FStream;            //判斷要下載的檔案夾是否存在            if (File.Exists(strFileName))            {                //開啟要下載的檔案                FStream = File.OpenWrite(strFileName);                //擷取已經下載的長度                SPosition = FStream.Length;                FStream.Seek(SPosition, SeekOrigin.Current);            }            else            {                //檔案不儲存建立一個檔案                FStream = new FileStream(strFileName, FileMode.Create);                SPosition = 0;            }            try            {                //開啟網路連接                HttpWebRequest myRequest = (HttpWebRequest)HttpWebRequest.Create("http://www.newxing.com/download/" + file);                if (SPosition > 0)                    myRequest.AddRange((int)SPosition);             //設定Range值                //向伺服器請求,獲得伺服器的回應資料流                Stream myStream = myRequest.GetResponse().GetResponseStream();                //定義一個位元組資料                byte[] btContent = new byte[512];                int intSize = 0;                intSize = myStream.Read(btContent, 0, 512);                while (intSize > 0)                {                    FStream.Write(btContent, 0, intSize);                    intSize = myStream.Read(btContent, 0, 512);                }                //關閉流                FStream.Close();                myStream.Close();                flag = true;        //返回true下載成功            }            catch (Exception)            {                FStream.Close();                flag = false;       //返回false下載失敗            }            return flag;        }    }}