2017-6-1 Linq 基础查询 （增删改查）

用小型人员管理系统的项目实战来练习linq的基础增删改查：

using System;
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") ;
        }
    }

    public string nationname 
    {
        get 
        {
            return nation1.nationname;
        }
    }
}


<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!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">
    <table style="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>编辑</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("nationname") %></td>
             <td>
                 <a href="update.aspx?id=<%#Eval("ids") %>">修改</a>
                 <a href="delete.aspx?id=<%#Eval("ids") %>">删除</a>
             </td>
        </tr>
                </ItemTemplate>
            </asp:Repeater>
    </table>
       <%-- 用户名：<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><br />
          密码：<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><br />
          昵称：<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox><br />
          性别：<asp:TextBox ID="TextBox4" runat="server"></asp:TextBox><br />
          生日：<asp:TextBox ID="TextBox5" runat="server"></asp:TextBox><br />
          民族：<asp:TextBox ID="TextBox6" runat="server"></asp:TextBox><br />
        <asp:Button ID="Button1" runat="server" Text="保存" />--%>
    </form>
</body>
</html>
using System;
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
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            using (masterDataClassesDataContext con = new masterDataClassesDataContext())
            {
                Repeater1.DataSource = con.users.ToList();
                Repeater1.DataBind();
            }
        }
        //Button1.Click += Button1_Click;
    }

    //void Button1_Click(object sender, EventArgs e)
    //{
    //    users u = new users();
    //    u.username = TextBox1.Text;
    //    u.password = TextBox2.Text;
    //    u.nickname = TextBox3.Text;
    //    u.sex = Convert.ToBoolean(TextBox4.Text);
    //    u.birthday = Convert.ToDateTime(TextBox5.Text);
    //    u.nation = TextBox6.Text;

    //    using (masterDataClassesDataContext con = new masterDataClassesDataContext())
    //    {
    //        con.users.InsertOnSubmit(u);
    //        con.SubmitChanges();

    //    }
    //}




   
}
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="delete.aspx.cs" Inherits="delete" %>

<!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">
    <div>
    
    </div>
    </form>
</body>
</html>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class delete : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string id = Request["id"];
        using (masterDataClassesDataContext con = new masterDataClassesDataContext()) 
        {
            ////根据主键值查出对应的这个对象
            //List<users> ulist = con.users.ToList();
            ////lambda表达式
            //users us = ulist.Where(r=>r.ids.ToString()==id).FirstOrDefault();
            users us = con.users.Where(r => r.ids.ToString() == id).FirstOrDefault();
           if(us!=null)
           {
            con.users.DeleteOnSubmit(us);
            con.SubmitChanges();
           }
        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class delete : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string id = Request["id"];
        using (masterDataClassesDataContext con = new masterDataClassesDataContext()) 
        {
            ////根据主键值查出对应的这个对象
            //List<users> ulist = con.users.ToList();
            ////lambda表达式
            //users us = ulist.Where(r=>r.ids.ToString()==id).FirstOrDefault();
            users us = con.users.Where(r => r.ids.ToString() == id).FirstOrDefault();
           if(us!=null)
           {
            con.users.DeleteOnSubmit(us);
            con.SubmitChanges();
           }
        }
    }
}
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="denglu.aspx.cs" Inherits="denglu" %>

<!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">
    <div>
        <h1>用户登录</h1>
    用户名：<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><br /><br />
        密码：<asp:TextBox ID="TextBox2"  TextMode="Password" runat="server"></asp:TextBox><br /><br />
        <asp:Button ID="Button1" runat="server" Text="登录" />
        <asp:Button ID="Button2" runat="server" Text="注册" />
    </div>
    </form>
</body>
</html>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class denglu : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Button1.Click += Button1_Click;
        Button2.Click += Button2_Click;
    }

    void Button2_Click(object sender, EventArgs e)
    {
        Response.Redirect("insert.aspx");
    }

    void Button1_Click(object sender, EventArgs e)
    {
        using (masterDataClassesDataContext con = new masterDataClassesDataContext())
        {
            string uname = TextBox1.Text;
            string pwd = TextBox2.Text;
            users u = con.users.Where(r => r.username == uname && r.password == pwd).FirstOrDefault();
            if (u != null)
            {

                Response.Write("<script>alert('登录成功！'); window.location.href='Default.aspx';</script>");

            }
            else
            {
                Response.Write("<script>alert('用户名或密码错误！');</script> ");
            }
        }
    }
}
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="insert.aspx.cs" Inherits="insert" %>

<!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>
    <script src="DatePicker/WdatePicker.js"></script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <h1>用户注册</h1>
        用户名：<asp:TextBox ID="txt_uname"  runat="server"></asp:TextBox><br /><br />
        密码：<asp:TextBox ID="txt_pwd" TextMode="Password" runat="server"></asp:TextBox><br /><br />
        昵称：<asp:TextBox ID="txt_nick" runat="server"></asp:TextBox><br /><br />
        性别：<asp:RadioButtonList ID="ra_sex" runat="server" RepeatLayout="Flow" RepeatDirection="Horizontal">
            <asp:ListItem Text="男" Selected="True" Value="True"></asp:ListItem>
            <asp:ListItem Text="女" Value="False"></asp:ListItem>
           </asp:RadioButtonList><br /><br />
        
        生日：<asp:TextBox ID="txt_bir" runat="server"></asp:TextBox><br /><br />
        民族：<asp:DropDownList ID="dr_nation" runat="server"></asp:DropDownList><br /><br />
        <asp:Button ID="Button1" runat="server" Text="确认注册" />
    </div>
    </form>
</body>
</html>
<script type="text/javascript">
    document.getElementById("txt_bir").onfocus = function () {
        WdatePicker({ readOnly: true, maxDate: '%y-%M-%d' });
    }


</script>
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="insert.aspx.cs" Inherits="insert" %>

<!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>
    <script src="DatePicker/WdatePicker.js"></script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <h1>用户注册</h1>
        用户名：<asp:TextBox ID="txt_uname"  runat="server"></asp:TextBox><br /><br />
        密码：<asp:TextBox ID="txt_pwd" TextMode="Password" runat="server"></asp:TextBox><br /><br />
        昵称：<asp:TextBox ID="txt_nick" runat="server"></asp:TextBox><br /><br />
        性别：<asp:RadioButtonList ID="ra_sex" runat="server" RepeatLayout="Flow" RepeatDirection="Horizontal">
            <asp:ListItem Text="男" Selected="True" Value="True"></asp:ListItem>
            <asp:ListItem Text="女" Value="False"></asp:ListItem>
           </asp:RadioButtonList><br /><br />
        
        生日：<asp:TextBox ID="txt_bir" runat="server"></asp:TextBox><br /><br />
        民族：<asp:DropDownList ID="dr_nation" runat="server"></asp:DropDownList><br /><br />
        <asp:Button ID="Button1" runat="server" Text="确认注册" />
    </div>
    </form>
</body>
</html>
<script type="text/javascript">
    document.getElementById("txt_bir").onfocus = function () {
        WdatePicker({ readOnly: true, maxDate: '%y-%M-%d' });
    }


</script>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class insert : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            using (masterDataClassesDataContext con = new masterDataClassesDataContext())
            {
                dr_nation.DataSource = con.nation.ToList();
                dr_nation.DataTextField = "nationname";
                dr_nation.DataValueField = "nationcode";
                dr_nation.DataBind();
                
              
               


            }
        }
        Button1.Click += Button1_Click;
    }

    void Button1_Click(object sender, EventArgs e)
    {
        users u = new users();
        u.username = txt_uname.Text;
        u.password = txt_pwd.Text;
        u.nickname = txt_nick.Text;

        u.sex = ra_sex.Items[0].Selected;
        u.birthday = Convert.ToDateTime(txt_bir.Text);
        u.nation = dr_nation.SelectedValue;
        using (masterDataClassesDataContext con = new masterDataClassesDataContext())
        {
            con.users.InsertOnSubmit(u);
            con.SubmitChanges();
            Response.Write("<script>alert('注册成功！'); window.location.href='denglu.aspx';</script>");
        }
    }
}
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="update.aspx.cs" Inherits="update" %>

<!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>
    <script src="DatePicker/WdatePicker.js"></script>
</head>
<body>
    <form id="form1" runat="server">
    <div>

        <h1>用户修改</h1>
        用户名：<asp:TextBox ID="txt_uname" ReadOnly="true" runat="server"></asp:TextBox><br /><br />
        密码：<asp:TextBox ID="txt_pwd" TextMode="Password" runat="server"></asp:TextBox><br /><br />
        昵称：<asp:TextBox ID="txt_nick" runat="server"></asp:TextBox><br /><br />
        性别：<asp:RadioButtonList ID="ra_sex" runat="server" RepeatLayout="Flow" RepeatDirection="Horizontal">
            <asp:ListItem Text="男" Selected="True" Value="True"></asp:ListItem>
            <asp:ListItem Text="女" Value="False"></asp:ListItem>
           </asp:RadioButtonList><br /><br />
        
        生日：<asp:TextBox ID="txt_bir" runat="server"></asp:TextBox><br /><br />
        民族：<asp:DropDownList ID="dr_nation" runat="server"></asp:DropDownList><br /><br />
        <asp:Button ID="Button1" runat="server" Text="确认修改" />
    </div>
    </form>
</body>
</html>
<script type="text/javascript">
    document.getElementById("txt_bir").onfocus = function ()
    {
        WdatePicker({ readOnly: true, maxDate: '%y-%M-%d' });
    }


</script>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class update : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Button1.Click += Button1_Click;
        string id=Request["id"];
        if(!IsPostBack)
        {
            using (masterDataClassesDataContext con = new masterDataClassesDataContext()) 
            {
                dr_nation.DataSource = con.nation.ToList();
                dr_nation.DataTextField = "nationname";
                dr_nation.DataValueField = "nationcode";
                dr_nation.DataBind();

                users u = con.users.Where(r=>r.ids.ToString()==id).FirstOrDefault();
                if (u == null) { Response.Write("<Script>alert('未查到此用户！') window.history.go(-1);</Script>"); }
                else 
                {
                    txt_uname.Text = u.username;
                    txt_nick.Text = u.nickname;
                    if(u.sex==false)
                    {
                        ra_sex.Items[1].Selected = true;
                    }
                    txt_bir.Text =Convert.ToDateTime( u.birthday).ToString("yyyy-MM-dd");

                    foreach (ListItem li in dr_nation.Items)
                    {
                        if(li.Value==u.nation)
                        {
                            li.Selected = true;
                        }
                    }
                }
            }
        }
    }

    void Button1_Click(object sender, EventArgs e)
    {
        string id = Request["id"];
        using (masterDataClassesDataContext con = new masterDataClassesDataContext())
        {
            users u = con.users.Where(r => r.ids.ToString() == id).FirstOrDefault();
            if(u!=null)
            {
                if(txt_pwd.Text.Length>0)
                {
                    u.password = txt_pwd.Text;
                    u.nickname = txt_nick.Text;
                    u.sex = ra_sex.Items[0].Selected;
                    u.birthday =Convert.ToDateTime( txt_bir.Text);
                    u.nation = dr_nation.SelectedValue;
                    con.SubmitChanges();
                    Response.Write("<script>alert('修改成功！'); window.location.href='Default.aspx';</script>");
                }
            }
        }
    }
}
<?xml version="1.0"?>
<!--
  有关如何配置 ASP.NET 应用程序的详细信息，请访问
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <connectionStrings>
    <add name="masterConnectionString" connectionString="Data Source=.;Initial Catalog=master;User ID=sa;Password=123"
      providerName="System.Data.SqlClient" />
  </connectionStrings>
  <system.web>
    <compilation debug="false" targetFramework="4.0">
      <assemblies>
        <add assembly="System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
      </assemblies>
    </compilation>
  </system.web>
</configuration>

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原文地址：https://www.cnblogs.com/zhengqian/p/6934995.html