点击日历控件出现 “未将对象引用设置到对象的实例。“
同一个页面有日历 还有投票功能，
点击日历的日期会使投票出错。
投票页面HTML源代码
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="toupiao.ascx.cs" Inherits="XmlVote.toupiao" %><fieldset> <legend accesskey="F" style="FONT-WEIGHT:bold;COLOR:#000000;font-size:12px" align=center> <%=VoteTitle%></legend> <ul style="list-style-type:none;margin-left:50px"> <%for(int i=0;i<xnl.Count;i++) { System.Xml.XmlNode xn = xnl.Item(i);%> <li> <input type=checkbox name="vote" value="<%=xn.SelectSingleNode("VoteID").InnerText%>" /><%=xn.SelectSingleNode("Title").InnerText%> <%}%> </li> </ul> <div align=center><asp:Button id="Vote" runat="server" Text="投票" OnClick="Vote_Click"></asp:Button> <input type=button value="查看结果" onclick="javascript:var url='vote/ShowVote.aspx?i=0&voteid=<%=Request.QueryString["VoteID"]%>';window.open(url,'_blank','left=10,top=20,width=675,height=360');return false;" style="height: 26px" /></div> </fieldset>using System;using System.Data;using System.Configuration;using System.Collections;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Xml;namespace XmlVote{ public partial class toupiao : System.Web.UI.UserControl { protected XmlNodeList xnl; protected string VoteTitle = ""; protected System.Web.UI.WebControls.Button Button1; private XmlDocument myDoc = new XmlDocument(); protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) BindXML("1"); } private void BindXML(string VoteID) { myDoc.Load(Server.MapPath("vote/DB_hyy.xml")); XmlNode xn = myDoc.SelectSingleNode("//VoteInfo[ID='" + VoteID + "']"); VoteTitle = xn.SelectSingleNode("VoteTitle").InnerText; xnl = xn.SelectNodes("Item"); } protected void Vote_Click(object sender, EventArgs e) { string VoteID = "1"; //通过Cookie记录投票 if (Request.Cookies["IsVote"] != null) { Response.Write("<script>alert('对不起,你已投过票!');document.location=document.location;</script>"); } else { if (Request.Form["Vote"] != null && Request.Form["Vote"] != "") { string[] votes = Request.Form["Vote"].Split(','); myDoc.Load(Server.MapPath("vote/DB_hyy.xml")); XmlNode xn = myDoc.SelectSingleNode("//VoteInfo[ID='" + VoteID + "']"); for (int i = 0; i < votes.Length - 1; i++) { XmlNode xn0 = xn.SelectSingleNode("Item[VoteID='" + votes[i] + "']"); xn0.SelectSingleNode("Count").InnerText = Convert.ToString(Convert.ToInt32(xn0.SelectSingleNode("Count").InnerText) + 1); } myDoc.Save(Server.MapPath("vote/DB_hyy.xml")); } Response.Cookies["IsVote"].Value = "true"; Response.Cookies["IsVote"].Expires.AddHours(1); Response.Write("<script>window.open('vote/ShowVote.aspx?i=0&voteid=" + VoteID + "','_blank','left=10,top=20,width=675,height=360');document.location='?voteid=" + VoteID + "';</script>"); } Response.End(); } }}