C#实现附件上传和下载功能

 <asp:Panel ID="Panel5" runat="server">
   <fieldset>
   <legend>整体活动效果:</legend>
   <nav class="navbar navbar-default" role="navigation">
    <table cellspacing="0" class="table table-hover" border="0" style="border-collapse: collapse;">
    <tbody>
     <tr>
     <td><strong>需求单名称</strong></td>
     <td colspan="2">
      <strong>添加附件</strong>
     </td>
     <td>附件名称</td>
     </tr>
     <tr>
     <td><asp:Literal ID="LtOrder" runat="server"></asp:Literal></td>
     <td>
     <asp:Button style="margin-right: -55px;" ID="btnImport" runat="server" Text="添加附件" class="btn btn-default" OnClick="btnImport_Click" /></td>
     <td class="Up_file">
      <asp:FileUpload ID="UpLoadTxt" runat="server" class="form-control" />
     </td>
     <td>
      <asp:Literal ID="LAccessory" runat="server"></asp:Literal>
     </td>
     </tr>
    </tbody>
    </table>
   </nav>
   </fieldset>
  </asp:Panel>

#region///上传，文件名称添加数据库，文件保存相应路径
 /// <summary>
 /// 添加附件
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="e"></param>
 protected void btnImport_Click(object sender,EventArgs e)
 {
  string res = "0";
  string fileName = UpLoadTxt.FileName;//获取要导入的文件名 
  if (fileName == null || fileName == "")
  {
  res = "2";
  }
  else
  {
  string savePath = Server.MapPath("~/UploadFiles/ChatLog/");
  FileOperatpr(fileName,savePath);
  string url = savePath + fileName;
  UpLoadTxt.SaveAs(url);
  SqlConnection conn = SqlHelperEx.ConnOpen("SPSDB");
  string ExtName = getFileExt(fileName).ToUpper();//获取上传文件名称
  // string ENDNmae = getFileEND(fileName).ToUpper(); //后缀名
  id = Request["id"];
  res = GetAccessory(conn,fileName,id);
  SqlHelperEx.ConnClose(conn);
  }
  if (res == "2")
  {
  Response.Write("<script>alert('没有要添加的文件,请选中文件后再操作!');window.location.href='SNSNeedingOrder_InfoListView.aspx?id=" + Request["id"] + "';</script>");
  }
  if (res == "0")
  {
  Response.Write("<script>alert('添加失败!');window.location.href='SNSNeedingOrder_InfoListView.aspx?id=" + Request["id"] + "';</script>");
  }
  if(res=="1") {
  Response.Write("<script>alert('添加成功!');window.location.href='SNSNeedingOrder_InfoListView.aspx?id=" + Request["id"] + "';</script>");
  }
  if (res == "3")
  {
  Response.Write("<script>alert('没有需求单，非法操作!');window.location.href='SNSNeedingOrder_InfoListView.aspx?id=" + Request["id"] + "';</script>");
  }
 }
 #region 辅助功能
 /// <summary>
 /// 获取上传文件的后缀名
 /// </summary>
 /// <param name="fileName"></param>
 /// <returns></returns>
 private string getFileEND(string fileName)
 {
  if (fileName.IndexOf(".") == -1)
  return "";
  string[] temp = fileName.Split('.');
  return temp[temp.Length - 1].ToLower();
 }
 /// <summary>
 /// //获取上传文件的名称
 /// </summary>
 /// <param name="fileName"></param>
 /// <returns></returns>
 private string getFileExt(string fileName)
 {
  if (fileName.IndexOf(".") == -1)
  return "";
  string file = "";
  string[] temp = fileName.Split(new[] { "." },StringSplitOptions.RemoveEmptyEntries);
  file = temp[0].ToLower();
 return file.ToLower();
 }

 
 private void FileOperatpr(string fileName,string savePath)
 {
  if (!Directory.Exists(savePath))
  {
  Directory.CreateDirectory(savePath);
  }
  if (File.Exists(savePath + fileName))
  {
  File.Delete(savePath + fileName);
  }
 }
 
 #endregion
 
 /// <summary>
 /// 添加文件名
 /// </summary>
 /// <param name="conn"></param>
 /// <param name="filename"></param>
 /// <param name="id"></param>
 private string GetAccessory(SqlConnection conn,string filename,string id)
 {
  string res = "0";
  if (id == "0" || id == "" || id == null)
  {
  res = "3";
  }
  else
  {
  if (filename == null || filename == "")
  {
   res = "2";
  }
  else
  {
   string strOrderID = id;
   string strFileName = filename;
  string strCreateUserId = Session["UserName"].ToString();
   StringBuilder strSql = new StringBuilder();
   // 生成SQL语句;
   strSql.AppendFormat("INSERT INTO BaseSNSAccessory(OrderID,FileName,CreateUserId) values( {0}",Environment.NewLine);
   strSql.AppendFormat(" @OrderID,@FileName,@CreateUserId) {0}",Environment.NewLine);
   SqlParameter[] parameters = {
      new SqlParameter("@OrderID",strOrderID),new SqlParameter("@FileName",strFileName),new SqlParameter("@CreateUserId",strCreateUserId),};
   // 执行
   int result = SqlHelperEx.ExecuteNonQuery(strSql.ToString(),conn,parameters);
   // 返回
   SqlHelperEx.ConnClose(conn);
  if (result == 1)
   {
   res = "1";
   }
   else
   {
   res = "0";
   }
  }
  }
  return res;
 }
 #endregion

 /// <summary>
 /// 获取附件
 /// </summary>
 /// <param name="conn"></param>
 /// <param name="id"></param>
 public void GetAccessory(SqlConnection conn,string id)
 {
  string strsql = "SELECT *,(SELECT OrderName FROM Order_Info WHERE IsValid=1 AND id=bs.OrderID AND IsValid=1) AS OrderName FROM BaseSNSAccessory AS bs WHERE bs.IsValid=1 and bs.OrderID="+id+" ORDER BY bs.id DESC";
  DataTable dt = SqlHelperEx.GetDataTable(strsql,conn);
 if (dt.Rows.Count == 0)
  {
  Ltlog.Text = "无数据";
  return;
  }
  string fileName = "";
  string str = "";
  for (int i = 0; i < dt.Rows.Count; i++)
  {
  fileName = dt.Rows[i]["FileName"].ToString();
  str += "<tr height="36" bgcolor="#FFFFFF">";
  str += "<td>" + dt.Rows[i]["OrderName"].ToString() + "</td>";
  str += "<td> <a href='/EcBossWeb/UploadFiles/ChatLog/" + fileName + "' >点击下载：" + fileName + "</a></td>";
  str += " </tr>";
  }
  LtOrdersory.Text = str.ToString();
 
  //string filePath = "";
 
  //FileStream fs = new FileStream(filePath,FileMode.Open); // 设置文件流,filePath为文件路径
  //byte[] bytes = new byte[(int)fs.Length];
  //fs.Read(bytes,bytes.Length); // 读取
  //fs.Close();
  //Response.ClearContent(); // 清楚缓冲区所有内容
  //Response.ClearHeaders(); // 清楚缓冲区所有头
  //Response.ContentType = "application/octet-stream"; // 设置输出流的Http MIME类型
  ////通知浏览器下载文件而不是打开
  //Response.AddHeader("Content-Disposition","attachment; filename=" + HttpUtility.UrlEncode(fileName,System.Text.Encoding.UTF8)); //fileName为需要下载的文件名
  //Response.BinaryWrite(bytes); // 写入输入流
  //Response.Flush(); // 向客户端发送数据流
  //Response.End();
 }