网站投票系统！-蒲公英云

一、数据库脚本

    需要建立两张表，脚本如下：
create table VoteTitle  --投票主题表
(
TitleID int identity primary key,--主题编号
Title varchar(200) not null,--主题信息
SumNumber int default 0,--主题的所有项目投票总数
Mode bit default 0,--0为单选，1为复选，默认为0
Status bit default 0--0表示关闭主题，1为打开主题，默认为0
)
go 
insert into VoteTitle(Title,Mode,Status)values('你对我们网站评价如何？',0,1)
insert into VoteTitle(Title,Mode,Status)values('请选择你喜欢的编程语言',0,0)
go
create table VoteItem--投票主题项目表
(
ItemID int identity primary key,--项目编号
Item varchar(200)not null,--项目信息
Number int default 0,--项目的投票总数
TitleID int references VoteTitle(TitleID)on delete cascade on update cascade
--设置级联关系，当对父表中的TtileID进行删除和更新时，会影响子表
)
go
insert into VoteItem(Item,TitleID)values('非常好','1')
insert into VoteItem(Item,TitleID)values('好','1')
insert into VoteItem(Item,TitleID)values('一般','1')
insert into VoteItem(Item,TitleID)values('差','1')
insert into VoteItem(Item,TitleID)values('很差','1')
go
insert into VoteItem(Item,TitleID)values('asp,net web开发语言','2')
insert into VoteItem(Item,TitleID)values('C# 窗体开发语言','2')
insert into VoteItem(Item,TitleID)values('html页面语言','2')
insert into VoteItem(Item,TitleID)values('JS脚本语言','2')
go
create trigger trigger_VoteItem on VoteItem for update--建立触发器
as
begin
    if update(Number)--当项目表的投票更新时
    begin
         update VoteTitle set SumNumber=SumNumber+1 where TitleID=(select TitleID from inserted)
    end
end
--触发器结束
go
select * from VoteTitle
select * from VoteItem
go

注意，这里只进行第一个主题的讨论，也就是说默认是让用户对网站进行评价，关于投票选择喜欢语言的主题这里不演示。
表的效果图如下：

二、页面编辑，这里有两张表，第一张是显示投票的页面ShowVote.aspx，第二张是显示投票结果的页面LookVote.aspx

  ShowVote.aspx页面的代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;
namespace VoteSystem
{
    public partial class ShowVote : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            Bind();
        }
        private void Bind()
        {  //数据库操作
              string str="Server=.;DataBase=Exercise;uid=sa;pwd=;";
            SqlConnection conn = new SqlConnection(str);
            string sql="select * from VoteTitle where Status=1";
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            DataSet ds = new DataSet();
            da.Fill(ds, "TitleTable");
            sql = "select *from VoteItem where TitleID=(select TitleID from VoteTitle where Status=1)";
            da = new SqlDataAdapter(sql, conn);
            da.Fill(ds, "ItemTable");
            DataView dv = ds.Tables["ItemTable"].DefaultView;
            dv.Sort = "ItemID asc";
            //获取主题
            lblTitle.Text = ds.Tables["TitleTable"].Rows[0]["Title"].ToString();
            //获取启用的主题的Mode来决定是用单选框还是复选框，这里我默认的主题是进行网站评论，那么就默认是RadiobuttonList（即单选框）
            bool Mode = Convert.ToBoolean(ds.Tables["TitleTable"].Rows[0]["Mode"]);
            hfMode.Value = Mode.ToString();
            if (Mode)
            {
                //表示选择的是复选
                CheckBoxList obj = new CheckBoxList();
                obj.BackColor = System.Drawing.ColorTranslator.FromHtml("#EDEDED");
                obj.ID = "listVoteItem";
                obj.Width = 180;
                obj.DataSource = dv;
                obj.DataTextField = "Item";
                obj.DataValueField = "ItemID";
                obj.DataBind();
                Panel1.Controls.Add(obj);
            }
            else
            {
                //表示添加的是单选
                RadioButtonList obj = new RadioButtonList();
                obj.DataSource = dv;
                obj.ID = "listVoteItem";
                obj.DataTextField = "Item";
                obj.DataValueField = "ItemID";
                obj.DataBind();
                Panel1.Controls.Add(obj);
            }
        }
        //投票按钮
        protected void btnVote_Click(object sender, EventArgs e)
        {
            string pass = string.Empty;
            if (Request.Cookies["pass"] == null)
            {
                pass = "";
            }
            else
            {
                pass = Request.Cookies["pass"].Value.ToString();//读取客户端cookies
            }
            if (pass == "pass")
            {
                Response.Write("<script language='javascript'>alert('你每天只能投票一次');history.back();</script>");
                Response.End();
            }
            else
            {   
                string str = "Server=.;DataBase=Exercise;uid=sa;pwd=;";
                SqlConnection conn = new SqlConnection(str);
                conn.Open();
                SqlCommand cmd = new SqlCommand();
                cmd.CommandType = CommandType.Text;
                cmd.Connection = conn;
                bool Mode = Convert.ToBoolean(hfMode.Value);//hfMode是隐藏控件，用于记录Mode
                if (Mode)
                {
                    CheckBoxList rb = (CheckBoxList)Panel1.FindControl("listVoteItem");
                    if (rb.SelectedIndex == -1)
                    {
                        Response.Write("<script language='javascript'>alert('你必须至少选择一项！');history.back();</script>");
                        Response.End();
                    }
                    else
                    {
                        //表示用户进行了选择
                        foreach (ListItem item in rb.Items)
                        {
                            if (item.Selected)
                            {
                                cmd.CommandText = "update VoteItem set Number=Number+1 where ItemID=" + item.Value.ToString();
                                cmd.ExecuteNonQuery();
                            }
                        }
                        Response.Cookies["pass"].Value = "pass";
                        Response.Cookies["pass"].Expires = DateTime.Now.AddDays(1);
                        Response.Write("<script language='javascript'>alert('投票成功！');history.back();</script>");
                        Response.End();
                    }
                }
                else
                {
                    //表示添加的是单选
                    RadioButtonList rb = (RadioButtonList)Panel1.FindControl("listVoteItem");
                    if (rb.SelectedIndex == -1)
                    {
                        Response.Write("<script language='javascript'>alert('你必须至少选择一项!');history.back();</script>");
                        Response.End();
                    }
                    else
                    {
                        //表示用户进行了选择
                        foreach (ListItem item in rb.Items)
                        {
                            if (item.Selected)
                            {
                                cmd.CommandText = "update VoteItem set Number=Number+1 where ItemID=" + item.Value.ToString();
                                cmd.ExecuteNonQuery();
                            }
                        }
                        Response.Cookies["pass"].Value = "pass";
                        Response.Cookies["pass"].Expires = DateTime.Now.AddDays(1);
                        Response.Write("<script language='javascript'>alert('投票成功！');history.back();</script>");
                        Response.End();
                    }
                    conn.Close();
                    conn.Dispose();
                }
            }
        }
        //查看按钮
        protected void btnLook_Click(object sender, EventArgs e)
        {
            Response.Redirect("LookVote.aspx");
        }
    }
}

由于LookVote.aspx页面需要有一些样式布局，毕竟要显示给用户，所以先给出Html代码，代码如下：

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="LookVote.aspx.cs" Inherits="VoteSystem.LookVote" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div style="height: 382px">
        <asp:Label ID="lblInfo" runat="server" Text="lblInfo"></asp:Label>
        <br />
        <asp:Label ID="lblTitle" runat="server" Text="lblTitle"></asp:Label>
    <asp:Repeater ID="Repeater1" runat="server">
    <HeaderTemplate>
    <table style="color:#333333; text-align:left; border:0 width:90%; background-color:#b18a02;
    font-size:12px; font-family:宋体;"
    cellpadding="2" cellspacing="1">
    <tr style="height:25px; background-color:#FFFFFF; text-align:center;">
        <td style="width:50px;"> </td>
         <td style="width:170px;">选项</td>
          <td style="width:170px;">比例</td>
           <td style="width:170px;">票数</td>
    </tr>
    </HeaderTemplate>
    <ItemTemplate>
    <tr style="height:25px; background-color:#FFFFFF; text-align:left;">
    <td style=" text-align:center;"><%#DataBinder.Eval(Container.DataItem,"ItemID") %>
    </td>
     <td><%#DataBinder.Eval(Container.DataItem,"Item") %>
    </td>
     <td><%#DataBinder.Eval(Container.DataItem,"ItemPercent","<img src='Images/1.jpg' height='15' width='{0}'>") %> 
     <%#DataBinder.Eval(Container.DataItem,"ItemPercent","{0}%") %>
    </td>
    <td style=" text-align:center;"><%#DataBinder.Eval(Container.DataItem,"Number") %>
    </td>
    </tr>
    </ItemTemplate>
    <FooterTemplate>
    <tr style="height:25px; background-color:#FFFFFF; text-align:center;">
        <td colspan="4">
        <asp:LinkButton ID="LinkButton1" runat="server" OnClientClick="javascript:winow.print();return false;">[打印]
        </asp:LinkButton>
         <asp:LinkButton ID="LinkButton2" runat="server" OnClientClick="javascript:winow.close();return false;">[关闭]
        </asp:LinkButton>
        </td>
        </tr>
        </table></FooterTemplate>
    </asp:Repeater>
    </div>
    </form>
</body>
</html>

其中，<%#DataBinder.Eval(Container.DataItem,”ItemPercent”,”“) %> <%#DataBinder.Eval(Container.DataItem,”ItemPercent”,”{0}%”) %>

这个单元格实现了最核心的柱形图的显示。

下面是LookVote.aspx的后台代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
namespace VoteSystem
{
    public partial class LookVote : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            string str = "Server=.;DataBase=Exercise;uid=sa;pwd=;";
            SqlConnection conn = new SqlConnection(str);
            string sql = "select a.Title,a.SumNumber,a.Mode,a.Status,b.*,case a.SumNumber when 0 then 0 else round(cast(b.Number as float)/cast(a.SumNumber as float)*100,2) end as ItemPercent from VoteTitle a,VoteItem b where a.TitleID=b.TitleID and a.Status=1";
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            DataSet ds = new DataSet();
            da.Fill(ds);
            Repeater1.DataSource = ds.Tables[0].DefaultView;
            Repeater1.DataBind();
            lblInfo.Text = "共有" + ds.Tables[0].Rows[0]["SumNumber"].ToString() + "人参加投票";
            lblTitle.Text = ds.Tables[0].Rows[0]["Title"].ToString();
        }
    }
}

这部分的重点是SQL语句，string sql = “select a.Title,a.SumNumber,a.Mode,a.Status,b.*,case a.SumNumber when 0 then 0 else round(cast(b.Number as float)/cast(a.SumNumber as float)*100,2) end as ItemPercent from VoteTitle a,VoteItem b where a.TitleID=b.TitleID and a.Status=1”;

为了求出百分比，必须将投票数（整型）转换为浮点型，避免整型除以整型=整型的错误结果。另外还需用 when 表达式 then 结果这样的语句来描述特殊情况（因为如果投票数0的话，就不能用项目票数/主题总票数这种单一的公式来计算了）

原设计图如下：

投票页面的后台外观