使用 linq 在网页上对用户信息增删改,组合查询,分页显示
using System;users--属性扩展
using System.Collections.Generic;
using System.Linq;
using System.Web;
/// <summary>
/// Users 的摘要说明
/// </summary>
public partial class Users
{
public string SexStr
{
get
{
return Convert.ToBoolean(_Sex) ? "男" : "女";
}
}
public string BirStr
{
get
{
return Convert.ToDateTime(_Birthday).ToString("yyyy年MM月dd日");
} //DateTime? 型,带问号,最好转换一下
}
public string Nationn
{
get
{
return Nation1.NationName;
}
}
}
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>前端
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
</head>
<body>
<form id="form1" runat="server">
<br /><br />
用户名:<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
性别:<asp:DropDownList ID="DropDownList2" runat="server">
<asp:ListItem Value="null" Text=""></asp:ListItem> <%--留下空白选项 全选--%>
<asp:ListItem value="true" >男</asp:ListItem>
<asp:ListItem value="false" >女</asp:ListItem>
</asp:DropDownList>
民族:<asp:DropDownList ID="DropDownList1" runat="server">
<asp:ListItem Value ="null" Text=""></asp:ListItem> <%--留下空白选项 全选--%>
</asp:DropDownList>
<asp:Button ID="Button1" runat="server" Text="查询" />
<br /><br />
<table style="width: 100%; text-align: center; background-color: navy">
<tr style="color: white">
<td>编号</td>
<td>用户名</td>
<td>密码</td>
<td>昵称</td>
<td>性别</td>
<td>生日</td>
<td>民族</td>
<td>操作</td>
</tr>
<asp:Repeater ID="Repeater1" runat="server">
<ItemTemplate>
<tr style="background-color: white">
<td><%#Eval("Ids") %></td>
<td><%#Eval("Username") %></td>
<td><%#Eval("Password") %></td>
<td><%#Eval("Nickname") %></td>
<td><%#Eval("SexStr") %></td>
<td><%#Eval("BirStr") %></td>
<td><%#Eval("Nationn") %></td>
<td>
设置
删除
</td>
</tr>
</ItemTemplate>
</asp:Repeater>
<tr>
<td style="color: white" >
共有 <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label> 条记录
</td>
</tr>
</table>
第[<asp:Label ID="Label2" runat="server" Text="1"></asp:Label>]页
共[<asp:Label ID="Label3" runat="server" Text="Label"></asp:Label>]页
<asp:Button ID="But_up" runat="server" Text="上一页" />
<asp:Button ID="But_dow" runat="server" Text="下一页" />
</form>
</body>
</html>
using System;后台代码
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class _Default : System.Web.UI.Page
{
int pagelist = 3; //每页显示3条数据
protected void Page_Load(object sender, EventArgs e)
{
Button1.Click += Button1_Click;
But_up.Click += But_up_Click;
But_dow.Click += But_dow_Click;
if (!IsPostBack)
{
using (Data0216_DataClassesDataContext con = new Data0216_DataClassesDataContext())
{
//绑定民族
//DropDownList1.DataSource = con.Nation.ToList();
//DropDownList1.DataTextField = "NationName";
//DropDownList1.DataValueField = "NationCode"; 用此法绑定数据无法留空白选项,
//DropDownList1.DataBind(); 空选项为此项全选
//绑定民族
foreach (Nation uu in con.Nation.ToList())
{
ListItem li = new ListItem();
li.Text = uu.NationName;
li.Value = uu.NationCode;
DropDownList1.Items.Add(li);
}
//绑定所有记录
List<Users> ulist = con.Users.ToList();
Repeater1.DataSource = ulist.Take(pagelist);
Repeater1.DataBind();
//共多少条记录
Label1.Text = ulist.Count.ToString();
//共多少页
Label3.Text = Convert.ToInt32(Math.Ceiling(Convert.ToDecimal(ulist.Count) / pagelist)).ToString();
}
}
}
//下一页
void But_dow_Click(object sender, EventArgs e)
{
using (Data0216_DataClassesDataContext con = new Data0216_DataClassesDataContext())
{
//获取下一页页数
int a = Convert.ToInt32(Label2.Text) +1;
//调方法绑定数据
Repeater1.DataSource = select(con).Skip((a-1)*pagelist).Take(pagelist);
Repeater1.DataBind();
//修改显示页数
Label2.Text = a.ToString();
}
}
//上一页
void But_up_Click(object sender, EventArgs e)
{
using (Data0216_DataClassesDataContext con = new Data0216_DataClassesDataContext())
{
//获取下一页页数
int a = Convert.ToInt32(Label2.Text) - 1;
//调方法绑定数据
Repeater1.DataSource = select(con).Skip((a-1)*pagelist).Take(pagelist);
Repeater1.DataBind();
//修改显示页数
Label2.Text = a.ToString();
}
}
//组合查询
void Button1_Click(object sender, EventArgs e)
{
using (Data0216_DataClassesDataContext con = new Data0216_DataClassesDataContext())
{
Repeater1.DataSource = select(con).Take(pagelist); ;
Repeater1.DataBind();
}
}
//查询方法
public List<Users> select(Data0216_DataClassesDataContext con)
{
List<Users> ulist = con.Users.ToList();
//用户名
if (TextBox1.Text.Trim().Length < 0)
{
ulist = ulist.Where(r => r.Username.Contains(TextBox1.Text.Trim())).ToList();
}
//性别
if (DropDownList2.SelectedValue != "null")
{
ulist = ulist.Where(r => r.Sex == Convert.ToBoolean(DropDownList2.SelectedValue)).ToList();
}
//民族
if (DropDownList1.SelectedValue != "null")
{
ulist = ulist.Where(r => r.Nation == DropDownList1.SelectedValue).ToList();
}
Label1.Text = ulist.Count.ToString();//共多少记录
//共多少页
Label3.Text = Convert.ToInt32(Math.Ceiling(Convert.ToDecimal(ulist.Count) / pagelist)).ToString();
return ulist;
}
}
-- 将组合查询写成一个方法,调用方法查询所有结果后,上下文对象关闭消失,
由于本案例中在绑定数据时存在扩展属性,所以需要再开一次数据库,需要再创建一个上下文对象,
所以在本案例中,查询方法需要传入一个上下文对象,在上一页、下一页中都要创建上下文对象,
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