ASP.NET实现文件断点续传代码

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
public partial class DFile : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void LinBtnDFile_Click(object sender, EventArgs e)
    {
        // 创建一比特数组
        byte[] buffer = new Byte[10240];
        // 指定要下载文件的路径.
        string filePath = @"D:爱智旮旯.rar";

        // 或取文件名包括扩展名
        string fileName = Path.GetFileName(filePath);
        Stream fileStream = null;
        try
        {
            // 打开文件
            fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
            Response.Clear();

            // 获取文件的大小
            long fileSize = fileStream.Length;

            long sum = 0;
            if (Request.Headers["Range"] != null)
            {
                Response.StatusCode = 206; // 表示返回到客户端的 HTTP 输出状态的整数。默认值为 200。
                sum = long.Parse(Request.Headers["Range"].Replace("bytes=", "").Replace("-", ""));
            }
            if (sum != 0)
            {
                Response.AddHeader("Content-Range", "bytes " + sum.ToString() + "-" + ((long)(fileSize)).ToString() + "/" + fileSize.ToString());
            }
            // 获取部分http头信息
            Response.AddHeader("Content-Length", ((long)(fileSize - sum)).ToString());
            Response.ContentType = "application/octet-stream";
            //获取文件来源
            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(Request.ContentEncoding.GetBytes(fileName)));
            // Response.Flush();
            fileStream.Position = sum;    //设置当前流位置
            fileSize = fileSize - sum;
            // 当文件大小大于0是进入循环
            while (fileSize > 0)
            {
                // 判断客户端是否仍连接在服务器
                if (Response.IsClientConnected)
                {
                    // 获取缓冲区中的总字节数.
                    int length = fileStream.Read(buffer, 0, 10240);

                    // 写入数据
                    Response.OutputStream.Write(buffer, 0, length);

                    // 将缓冲区的输出发送到客户端
                    Response.Flush();

                    buffer = new Byte[10240];
                    fileSize = fileSize - length;
                }
                else
                {
                    //当用户断开后退出循环
                    fileSize = -1;
                }
            }
        }
        catch (Exception ex)
        {
            Response.Write("Error : " + ex.Message);
        }
        finally
        {
            if (fileStream != null)
            {
                //关闭文件
                fileStream.Close();
            }
            Response.End();
        }
    }
}