如合判断下载已经结束？

Question

 FileInfo DownloadFile = new FileInfo(path);
            Response.Clear();
            Response.ClearHeaders();
            Response.Buffer = false;
            Response.ContentType = "application/octet-stream";
            Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(DownloadFile.FullName, System.Text.Encoding.UTF8).Replace("+", "%20"));
            Response.AppendHeader("Content-Length", DownloadFile.Length.ToString());
            Response.WriteFile(DownloadFile.FullName);
            Response.Flush();
            Response.End();将文件下载，我现在想捕捉到他何时完成，请高手指点。

Answer 1

webform似乎没有这个事件
你说的是winform的进度条吧

Answer 2

可以采用分批读取数据的方法，这样就可以判断下载是否完成，参考下面的代码：
try {
                // Open the file.
                iStream = new System.IO.FileStream(file, FileMode.Open, FileAccess.Read, FileShare.Read);
                // Total bytes to read:
                dataToRead = iStream.Length;                Response.ContentType = "Application/octet-stream";
                Response.AddHeader("Content-Disposition", "attachment;filename=" + name + "." + ext);
                Response.AddHeader("Content-Length", dataToRead.ToString());                while (dataToRead > 0) {
                    // Verify that the client is connected.
                    if (Response.IsClientConnected) {
                        // Read the data in buffer.
                        length = iStream.Read(buffer, 0, FILE_BUFFER);                        // Write the data to the current output stream.
                        Response.OutputStream.Write(buffer, 0, length);                        // Flush the data to the HTML output.
                        Response.Flush();                        buffer = new Byte[FILE_BUFFER];
                        dataToRead = dataToRead - length;
                    } else {
                        //prevent infinite loop if user disconnects
                        dataToRead = -1;
                    }
                    // Download finished
                }
            } catch (Exception ex) {
                Utility.LogUtility.WriteToLog(ex, this.GetType(), "下载文件错误");
                throw ex;
            } finally {
                if (iStream != null) {
                    iStream.Close();
                }
            }

Answer 3

除非文件特别小，比如1KB或以下，否则永远不要使用WriteFile去下载文件。