Stream下载文件取消后再点击下载文件被占用解决思路

2012-02-24

Stream下载文件取消后再点击下载文件被占用代码如下：C# codecontext.Response.ContentType text/plain

Stream下载文件取消后再点击下载文件被占用
代码如下：

C# code

context.Response.ContentType = "text/plain";            string filePath = context.Request.Params["path"];//文件相对路径            if (FileExists(context.Server.MapPath(filePath)))            {                // 允许共享                System.IO.Stream input = new System.IO.FileStream(context.Server.MapPath(filePath), System.IO.FileMode.Open, System.IO.FileAccess.ReadWrite, System.IO.FileShare.Inheritable);                context.Response.ContentType = "application/octet-stream";                //文件名                string fileName = System.IO.Path.GetFileName(filePath);                //文件名编码                string encodingFileName = context.Server.UrlEncode(fileName).Replace('+', ' ');                context.Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}", encodingFileName));                // 输出到 this.Response.OutputStream 中                System.IO.Stream output = context.Response.OutputStream;                // 创建一个块缓冲                byte[] buffer = new byte[10 * 1024];                // 手工关闭输出的缓存                context.Response.BufferOutput = false;                TransmitFile(input, output, buffer);                output.Close();                input.Close();                context.Response.End();            }

问题是点击下载，弹出下载对话框，取消，再点击下载，报错，文件被进程占用。该怎么改进，谢谢！

[解决办法]
下载

C# code

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;            }        }    }} 
 
[解决办法]
C# codeusing 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;            }        }    }}
[解决办法]
为什么不直接用
 
 
Response.TransmitFile(string filename)
[解决办法]
TransmitFile(input, output, buffer);  

怎么实现的？我记得 Response.TransmitFile 只有一个参数： FileName。
且是不缓存直接输出到客户端的。

如果文件不是太大，完全可以直接用 Response.TransmitFile 也不要自己用 FileStream 打开文件。

另外，注意你 FileStream 的最后一个参数： System.IO.FileShare.Inheritable
如果是可读的话应该是 System.IO.FileShare.Read  


[解决办法]
System.IO.Stream input = new System.IO.FileStream(context.Server.MapPath(filePath), System.IO.FileMode.Open, System.IO.FileAccess.ReadWrite, System.IO.FileShare.Inheritable);

改成这样试试：
System.IO.Stream input = new System.IO.FileStream(context.Server.MapPath(filePath), System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);

[解决办法]
TransmitFile(input, output, buffer);  

怎么实现的？我记得 Response.TransmitFile 只有一个参数： FileName。
且是不缓存直接输出到客户端的。

如果文件不是太大，完全可以直接用 Response.TransmitFile 也不要自己用 FileStream 打开文件。

另外，注意你 FileStream 的最后一个参数： System.IO.FileShare.Inheritable
如果是可读的话应该是 System.IO.FileShare.Read ，且你只是下载，FileAccess用不着ReadWrite吧


[解决办法]
探讨
代码如下：C# code
context.Response.ContentType = "text/plain";
            string filePath = context.Request.Params["path"];//文件相对路径
            if (FileExists(context.Server.MapPath(filePath)))
         ……

[解决办法]
Response.TransmitFile（string filename）

简单好用！

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Stream下载文件取消后再点击下载文件被占用解决思路