C#中对文件的上传下载操作总结（下载后点击删除按钮总是提示进程被占用）

最近做项目时总是用到上传下载功能，网上搜了一下，这种功能很简单，所以没有把它当作一个难点，没想到后来经常碰到文件资源被占用的问题，文件“。。。。。。\Download\20142m10d417991a346.docx”正由另一进程使用，因此该进程无法访问此文件。下载代码如下：

protected void BtnTextLoad_Clik(string filePath, string fileName)
        {
            if (filePath != "" && fileName != "")
            {
                string a = Server.MapPath(filePath);//路径
                // string fileNames = fileName + a.Substring(a.LastIndexOf("."), a.Length - a.LastIndexOf("."));
                string filepath = a.Substring(0, a.LastIndexOf("view")) + filePath;
                System.IO.FileInfo fileInfo = new System.IO.FileInfo(filepath);
                if (fileInfo.Exists == true)
                {
                    const long ChunkSize = 102400;//100K 每次读取文件，只读取100K，这样可以缓解服务器的压力
                    byte[] buffer = new byte[ChunkSize];
                    Response.Clear();
                    System.IO.FileStream iStream= System.IO.File.OpenRead(filepath);
                    long dataLengthToRead = iStream.Length;//获取下载的文件总大小
                    Response.ContentType = "application/octet-stream";
                    Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));
                    while (dataLengthToRead > 0 && Response.IsClientConnected)
                    {
                        int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小
                        Response.OutputStream.Write(buffer, 0, lengthRead);
                        Response.Flush();
                        dataLengthToRead = dataLengthToRead - lengthRead;
                    }
                    Response.Close();                 }
            }
            else
            {
                Response.Write("<script type=\"text/javascript\">alert(\"下载的文件不存在！\");\"</script> ");
            }

 

查看代码，明明已经有Response.Close();来结束响应了。后来经过查找资料，发现还需关闭刚刚创建的iStream，即在Response.Close后面添加上iStream.Close().这么一个细节，花费了我近一天的时间。

iStream