C#实现附件上传和下载功能

通常情况下，我们会遇到各种上传附件的情况，以及上传后需要下载，文档格式各种各样，当然这个过程中也是报不同错误，还是一个原则，具体问题，具体分析：需求图：

上传代码实现：
 aspx代码：

 <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>

cs代码：  

#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

下载实现：

 /// <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, 0, 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();
 }

以上就是为大家分享的c#实现附件上传和下载功能的关键代码，希望对大家的学习有所帮助。