最简单的上传文件

前台

      <div class="upload">
          <asp:FileUpload ID="FileUpload1" runat="server"/>
          <asp:Button ID="BtnLoad" runat="server" Text="上传" onclick="BtnLoad_Click"/>
     </div>

后台

  protected void BtnLoad_Click(object sender, EventArgs e)
        {
            if (this.FileUpload1.FileName == "")
            {
                Response.Write("<script>alert('没有上传文件')</script>");
                return;
            }
            DataAccess.dataDR datadr = new dataDR();
            datadr.delete("delete from dbo.autozhesuanxisubiao");
            string fileName = DateTime.Now.ToString("yyMMddhhmmss") + ".xls";
            string path = Server.MapPath("~/upload/excel/") + fileName;
            FileUpload1.SaveAs(path);

            if (path != null)
            {
                DataAccess.LoadSourceToDataAccess.loadAutoZhesSuangXiShu(path);
                Response.Write("<script>alert('上传成功！')</script>");
            }
            else
            {
                Response.Write("<script>alert('没有上传文件')</script>");
            }
        }