Application：
全局公共变量组
存放位置：服务器
特点：所有访问用户都是访问同一个变量，但只要服务器不停机，变量一直存在于服务器的内存中，不要使用循环大量的创建Application对象，可能会造
成服务器崩溃。
生命周期：永久，只要服务器不停机
使用方法：与Session一样
ViewState：
用于记录页面的一些状态，就像人的病例，比如当执行提交后，网页可以保留一些已经输入的文本框而非清空
webform中微软已经给我们做好了这个对象，自带此功能。
webform中一共6个内置对象：Request Response Session Cookie Application ViewState
分页：
为了用户查看以及页面加载速度，查看大量数据时需要进行分页操作，
主要通过查询语句以及各种判断来实现
例如：食品信息的展示
界面代码：
1 <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> 2 3 <!DOCTYPE html> 4 5 <html xmlns="http://www.w3.org/1999/xhtml"> 6 <head id="Head1" runat="server"> 7 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 8 <title></title> 9 </head> 10 <body> 11 <form id="form1" runat="server"> 12 <div> 13 14 <asp:Repeater ID="Repeater1" runat="server"> 15 <HeaderTemplate> 16 17 <table style=" 100%; text-align: center; background-color: navy;"> 18 <thead> 19 <tr style="color: white;"> 20 <%--<td>ids</td>--%> 21 <td>食品编号</td> 22 <td>食品名称</td> 23 <td>食品价格</td> 24 <td>食品制造商</td> 25 </tr> 26 </thead> 27 <tbody> 28 </HeaderTemplate> 29 30 <ItemTemplate> 31 32 <tr style="background-color: white;"> 33 <%--<td><%#Eval("ids") %></td>--%> 34 <td><%#Eval("ids") %></td> 35 <td><%#Eval("foodname") %></td> 36 <td><%#Eval("foodprice") %></td> 37 <td><%#Eval("foodmade") %></td> 38 39 </tr> 40 41 </ItemTemplate> 42 <FooterTemplate> 43 </tbody> 44 </table> 45 </FooterTemplate> 46 </asp:Repeater> 47 48 当前第【<asp:Label ID="Label_NowPage" runat="server" Text="Label"></asp:Label>】页 49 共【<asp:Label ID="Label_MaxPage" runat="server" Text="Label"></asp:Label>】页 50 <asp:LinkButton ID="btn_first" runat="server">首页</asp:LinkButton> 51 52 <asp:LinkButton ID="btn_prev" runat="server">上一页</asp:LinkButton> 53 54 <asp:LinkButton ID="btn_next" runat="server">下一页</asp:LinkButton> 55 56 <asp:LinkButton ID="btn_last" runat="server">末页</asp:LinkButton> 57 58 <asp:DropDownList ID="DropDownList1" AutoPostBack="true" runat="server"></asp:DropDownList> 59 <asp:Button ID="Button1" runat="server" Text="跳转" /> 60 61 62 </div> 63 </form> 64 </body> 65 </html>
实体类：
1 using System; 2 using System.Collections; 3 using System.Collections.Generic; 4 using System.Data.SqlClient; 5 using System.Linq; 6 using System.Web; 7 8 /// <summary> 9 /// foodData 的摘要说明 10 /// </summary> 11 public class foodData 12 { 13 SqlConnection conn = null; 14 SqlCommand cmd = null; 15 16 public foodData() 17 { 18 conn = new SqlConnection("server=.;database=Data0216;user=sa;pwd=123"); 19 cmd = conn.CreateCommand(); 20 } 21 22 public List<food> SelectAll() 23 { 24 List<food> clist = new List<food>(); 25 cmd.CommandText = "select *from food"; 26 conn.Open(); 27 SqlDataReader dr = cmd.ExecuteReader(); 28 while (dr.Read()) 29 { 30 food c = new food(); 31 c.Ids = Convert.ToInt32(dr["ids"]); 32 c.foodname = dr["foodname"].ToString(); 33 c.foodprice = Convert.ToDecimal(dr["foodprice"]); 34 c.foodmade = dr["foodmade"].ToString(); 35 clist.Add(c); 36 } 37 conn.Close(); 38 return clist; 39 } 40 41 42 public List<food> Select(int pcount, int pnumber) 43 { 44 List<food> clist = new List<food>(); 45 cmd.CommandText = "select top " + pcount + " * from food where ids not in(select top " + (pcount * (pnumber - 1)) + " ids from food)"; 46 conn.Open(); 47 SqlDataReader dr = cmd.ExecuteReader(); 48 while (dr.Read()) 49 { 50 food c = new food(); 51 c.Ids = Convert.ToInt32(dr["ids"]); 52 c.foodname = dr["foodname"].ToString(); 53 c.foodprice = Convert.ToDecimal(dr["foodprice"]); 54 c.foodmade = dr["foodmade"].ToString(); 55 clist.Add(c); 56 } 57 conn.Close(); 58 return clist; 59 } 60 61 62 public int SelectCount() 63 { 64 int a = 0; 65 cmd.CommandText = "select count(*) from food"; 66 conn.Open(); 67 SqlDataReader dr = cmd.ExecuteReader(); 68 dr.Read(); 69 a = Convert.ToInt32(dr[0]); 70 conn.Close(); 71 return a; 72 } 73 74 75 76 public List<food> SelectAll(string tsql, Hashtable hh) 77 { 78 List<food> clist = new List<food>(); 79 cmd.CommandText = tsql; 80 cmd.Parameters.Clear(); 81 foreach(string s in hh.Keys) 82 { 83 cmd.Parameters.Add(s, hh[s]); 84 } 85 conn.Open(); 86 SqlDataReader dr = cmd.ExecuteReader(); 87 while (dr.Read()) 88 { 89 food c = new food(); 90 c.Ids = Convert.ToInt32(dr["ids"]); 91 c.foodname = dr["foodname"].ToString(); 92 c.foodprice = Convert.ToDecimal(dr["foodprice"]); 93 c.foodmade = dr["foodmade"].ToString(); 94 clist.Add(c); 95 } 96 conn.Close(); 97 return clist; 98 } 99 100 }
后台代码：
1 using System; 2 using System.Collections.Generic; 3 using System; 4 using System.Collections.Generic; 5 using System.Linq; 6 using System.Web; 7 using System.Web.UI; 8 using System.Web.UI.WebControls; 9 10 public partial class _Default : System.Web.UI.Page 11 { 12 int PageCount = 5; //每页显示条数 13 14 protected void Page_Load(object sender, EventArgs e) 15 { 16 if (!IsPostBack) 17 { 18 Label_NowPage.Text = "1"; 19 Label_MaxPage.Text = MaxPageNumber().ToString(); 20 btn_prev.Enabled = false; 21 btn_first.Enabled = false; 22 23 Repeater1.DataSource = new foodData().Select(PageCount, 1); 24 Repeater1.DataBind(); 25 26 27 int max = MaxPageNumber(); 28 DropDownList1.Items.Clear(); 29 for (int i = 1; i <= max; i++) 30 { 31 DropDownList1.Items.Add(new ListItem(i.ToString(), i.ToString())); 32 } 33 } 34 35 36 37 DropDownList1.SelectedIndexChanged += Button1_Click; 38 btn_first.Click += btn_first_Click;//首页按钮 39 btn_prev.Click += btn_prev_Click; 40 btn_next.Click += btn_next_Click; 41 btn_last.Click += btn_last_Click; 42 Button1.Click += Button1_Click; 43 } 44 45 void Button1_Click(object sender, EventArgs e) 46 { 47 //获取当前页，计算要看的下一页的页号 48 int nextPage = Convert.ToInt32(DropDownList1.SelectedValue); 49 50 //按照获取的页数绑定相应的数据 51 Repeater1.DataSource = new foodData().Select(PageCount, nextPage); 52 Repeater1.DataBind(); 53 54 //修改显示页数 55 Label_NowPage.Text = nextPage.ToString(); 56 57 if (nextPage == 1) 58 { 59 btn_first.Enabled = false; 60 btn_prev.Enabled = false; 61 btn_next.Enabled = true; 62 btn_last.Enabled = true; 63 } 64 else if (nextPage == MaxPageNumber()) 65 { 66 btn_first.Enabled = true; 67 btn_prev.Enabled = true; 68 btn_next.Enabled = false; 69 btn_last.Enabled = false; 70 } 71 else 72 { 73 btn_first.Enabled = true; 74 btn_prev.Enabled = true; 75 btn_next.Enabled = true; 76 btn_last.Enabled = true; 77 } 78 } 79 80 void btn_first_Click(object sender, EventArgs e) 81 { 82 //按照获取的页数绑定相应的数据 83 Repeater1.DataSource = new foodData().Select(PageCount, 1); 84 Repeater1.DataBind(); 85 86 //修改显示页数 87 Label_NowPage.Text = "1"; 88 89 90 btn_first.Enabled = false; 91 btn_prev.Enabled = false; 92 btn_next.Enabled = true; 93 btn_last.Enabled = true; 94 } 95 96 void btn_prev_Click(object sender, EventArgs e) 97 { 98 //获取当前页，计算要看的下一页的页号 99 int nextPage = Convert.ToInt32(Label_NowPage.Text) - 1; 100 101 //按照获取的页数绑定相应的数据 102 Repeater1.DataSource = new foodData().Select(PageCount, nextPage); 103 Repeater1.DataBind(); 104 105 //修改显示页数 106 Label_NowPage.Text = nextPage.ToString(); 107 108 if (nextPage <= 1) 109 { 110 btn_first.Enabled = false; 111 btn_prev.Enabled = false; 112 } 113 btn_next.Enabled = true; 114 btn_last.Enabled = true; 115 } 116 117 void btn_next_Click(object sender, EventArgs e) 118 { 119 //获取当前页，计算要看的下一页的页号 120 int nextPage = Convert.ToInt32(Label_NowPage.Text) + 1; 121 122 ////判断是否有下一页 123 //if (nextPage > MaxPageNumber()) 124 //{ 125 // return; 126 //} 127 128 //按照获取的页数绑定相应的数据 129 Repeater1.DataSource = new foodData().Select(PageCount, nextPage); 130 Repeater1.DataBind(); 131 132 //修改显示页数 133 Label_NowPage.Text = nextPage.ToString(); 134 135 if (nextPage >= MaxPageNumber()) 136 { 137 btn_next.Enabled = false; 138 btn_last.Enabled = false; 139 } 140 btn_prev.Enabled = true; 141 btn_first.Enabled = true; 142 } 143 144 void btn_last_Click(object sender, EventArgs e) 145 { 146 int hehe = MaxPageNumber(); 147 148 //按照获取的页数绑定相应的数据 149 Repeater1.DataSource = new foodData().Select(PageCount, hehe); 150 Repeater1.DataBind(); 151 152 //修改显示页数 153 Label_NowPage.Text = hehe.ToString(); 154 155 156 btn_prev.Enabled = true; 157 btn_first.Enabled = true; 158 btn_next.Enabled = false; 159 btn_last.Enabled = false; 160 } 161 162 163 public int MaxPageNumber() 164 { 165 int a = 0; 166 int maxcount = new foodData().SelectCount(); 167 decimal d = Convert.ToDecimal(maxcount) / PageCount; 168 a = Convert.ToInt32(Math.Ceiling(d)); 169 return a; 170 } 171 }