<div id="downloadInfo" runat="server"></div>

// 下载附件的选择
  $attach = $("#download-list");
  var arr = []
  $attach.on('click', '.no', function () {
    $(this).toggleClass('checked');//设置和移除，选中与不选中
    if ($(this).hasClass('checked')) {
      var guid = $(this).children("#hidAttachGuid").val();
      arr.push(guid);//将guid添加到arr数组中
      
    }
    else
    {//取消选中时
      var guid = $(this).children("#hidAttachGuid").val();
      var n = arr.indexOf(guid);
      if (n != -1)
      arr.splice(n, 1);//将指定不选中的guid移除arr数组
    }
    $("[id$='arrayGuid']").val(arr);
  });

<button type='button' class='one-download' onclick='download()'>一键下载</button>
function download() {
      $("#btnDownload").click();
    }

<span style="display: none">
   <asp:Button ID="btnDownload" OnClick="btnDownload_Click" Text="确定" runat="server" />
    <input type="text" id="arrayGuid" runat="server" />
</span>

protected void btnDownload_Click(object sender, EventArgs e)
    {
      //ZipFileByCode();
      string attachGuid = arrayGuid.Value;
      string[] sArray = attachGuid.Split(',');

     
      List<string> list = new List<string>();
      foreach (string i in sArray)
      {
        //这里是循环得到指定需要下载的所有id
 
      }

      Download(list, ""+lblCourseName.Text+"相关附件材料.rar");
    }

public void ZipFileByCode()
    {
      MemoryStream ms = new MemoryStream();
      byte[] buffer = null;

      using (ZipFile file = ZipFile.Create(ms))
      {
        file.BeginUpdate();
        file.NameTransform = new MyNameTransfom();//通过这个名称格式化器，可以将里面的文件名进行一些处理。默认情况下，会自动根据文件的路径在zip中创建有关的文件夹。

        file.Add(Server.MapPath("/Content/images/img01.jpg"));
        file.CommitUpdate();

        buffer = new byte[ms.Length];
        ms.Position = 0;
        ms.Read(buffer, 0, buffer.Length);
      }


      Response.AddHeader("content-disposition", "attachment;filename=test.zip");
      Response.BinaryWrite(buffer);
      Response.Flush();
      Response.End();

    }

private void Download(IEnumerable<string> files, string zipFileName)
    {
      //根据所选文件打包下载 
      MemoryStream ms = new MemoryStream();
      byte[] buffer = null;
      using (ZipFile file = ZipFile.Create(ms))
      {
        file.BeginUpdate();
        file.NameTransform = new MyNameTransfom();//通过这个名称格式化器，可以将里面的文件名进行一些处理。默认情况下，会自动根据文件的路径在zip中创建有关的文件夹。 

        foreach (var item in files)
        {
          file.Add(item);
        }
        //file.Add(Server.MapPath("../../BigFileUpLoadStorage/1.png"));
        file.CommitUpdate();
        buffer = new byte[ms.Length];
        ms.Position = 0;
        ms.Read(buffer, 0, buffer.Length);
      }
      Response.AddHeader("content-disposition", "attachment;filename=" + zipFileName);
      Response.BinaryWrite(buffer);
      Response.Flush();
      Response.End();
    }

public class MyNameTransfom : ICSharpCode.SharpZipLib.Core.INameTransform
  {

    #region INameTransform 成员

    public string TransformDirectory(string name)
    {
      return null;
    }

    public string TransformFile(string name)
    {
      return Path.GetFileName(name);
    }

    #endregion
  }