asp.net 实现文件下载

Question

本帖最后由 sdc102015 于 2012-05-16 18:01:46 编辑

Answer 1

参考：
http://www.cnblogs.com/insus/articles/1411761.html
http://www.cnblogs.com/insus/articles/2003336.html

Answer 2

//取数据表         
DataRow objDataRow = objMedia.GetFileByPrimaryKey(id).Rows[0];
objMedia和id是什么？

Answer 3

参考我之前的下载代码:自己优化哈
using System;
using System.Collections;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;namespace Asiastar.NR.Ajax
{
    /// <summary>
    /// $codebehindclassname$ 的摘要说明
    /// </summary>
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    public class Handler1 : IHttpHandler
    {        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";            string id = context.Request["id"].ToString();//获取资源的编号
            System.IO.Stream iStream = null;
            byte[] buffer = new Byte[10000];
            int length;
            long dataToRead;
            NRBLL.File bf = new Asiastar.NRBLL.File();
            Guid guid = new Guid(id);
            if (bf.FN_SerchPathByFileId(guid).Tables[0].Rows[0]["FilePath"] != null)//判断数据库路径是否存在  
            {
                string filepath = bf.FN_SerchPathByFileId(guid).Tables[0].Rows[0]["FilePath"].ToString();//获取资源完整路径    D:\资源文件\600cc139-14cf-448e-9e50-daa972d35e01.jpg
                string Oidfilename = bf.FN_SerchPathByFileId(guid).Tables[0].Rows[0]["FileNam"].ToString();//旧文件名称
                //string filename = System.IO.Path.GetFileName(filepath);//获取文件名称+后缀名 600cc139-14cf-448e-9e50-daa972d35e01.JPG
                //int index = filepath.IndexOf(".");
                //string filetype = filepath.Substring(index).ToLower();//后缀名
                //string newfilename = Oidfilename;
                //string filepath1 = bf.FN_SerchPathByFileId(guid).Tables[0].Rows[0]["FilePath"].ToString().Substring(0,filepath.Length - 8);
                try
                {
                    string fileName = HttpUtility.UrlEncode(System.Text.Encoding.UTF8.GetBytes(Oidfilename));//解码(注意这里2层解码)
                    Oidfilename = Oidfilename.Replace("+", "%20");  //将“+”替换成“空格”
                    iStream = new System.IO.FileStream(filepath, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);
                    dataToRead = iStream.Length;
                    context.Response.ContentType = "application/octet-stream";
                    context.Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(Oidfilename, System.Text.Encoding.UTF8));  //下载的时候下载原来的文件名称
                    while (dataToRead > 0)
                    {
                        if (context.Response.IsClientConnected)
                        {
                            length = iStream.Read(buffer, 0, 10000);
                            context.Response.OutputStream.Write(buffer, 0, length);
                            context.Response.Flush();
                            buffer = new Byte[10000];
                            dataToRead = dataToRead - length;
                        }
                        else
                        {
                            dataToRead = -1;
                        }
                    }                }
                catch (Exception ex)
                {
                    NR.Error.Log.LogType(ex.ToString());
                }
                finally
                {
                    if (iStream != null)
                    {
                        iStream.Close();
                    }
                }
            }
            else
            {
                NR.Error.Log.LogType("找不到文件!");
            }
        }
        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

Answer 4

 public static void DownLoadFile(string file)
    {
        HttpContext.Current.Response.Clear();
        System.IO.FileInfo finfo = new System.IO.FileInfo(file);
        if (!finfo.Exists)
        {
            oJavaScript.Alert("文件不存在");
            return;
        }
        else
        {
            string reportfile = finfo.FullName;
            string filename = finfo.Name;
            HttpContext.Current.Response.Buffer = true;
            HttpContext.Current.Response.ContentType = "application/octet-stream";
            HttpContext.Current.Response.AddHeader("Content-Disposition", "attachment;FileName=" + HttpUtility.UrlEncode(filename,System.Text.Encoding.UTF8));
            HttpContext.Current.Response.WriteFile(reportfile);
            HttpContext.Current.Response.End();
        }
    }
上面的代码，我这里可以

Answer 5

错误是这个意思：
Sys.WebForms.PageRequestManagerParserErrorExeception：从服务器收到的消息不能被解析。这种错误的常见原因是响应时调用细节修改：误差解析附近'□ □ □ □

Answer 6

直接 Response.Redirect   转像地址试试，你用UpdatePanel 了？

Answer 7

http://hi.baidu.com/a_magic/blog/item/2d9c2811fe90f9cca7ef3fa8.html 参考这个

Answer 8

好消息：
大功告成！分享下：
我建了个一般处理程序，代码如下：
public class FileDownLoad : IHttpHandler 
{     
public void ProcessRequest(HttpContext context)     
{         
System.IO.FileInfo file = new System.IO.FileInfo(context.Request["filepath"].ToString());         context.Response.ContentType = "image/pic/pdf/bmp/png/gif/jpg/swf"; //例: "image/gif"         context.Response.AddHeader("Content-Disposition", "attachment; filename=\"" + HttpUtility.UrlEncode(file.Name) + "\"");         context.Response.TransmitFile(System.Web.Hosting.HostingEnvironment.MapPath(context.Request["filepath"].ToString()));  //常用方法, 大文件需换成Stream分段下载     }      public bool IsReusable     
{         
get         
{             
return true;         
}     
} 
}
然后在下载事件中写如下代码：
Response.Redirect("FileDownLoad.ashx?filepath="+filePath);“FileDownLoad.ashx”为我创建的一般处理程序页面，“filePath”为传过去的虚拟路径
跟三楼的差不多，谢谢各位了啊……