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linq的创建 和 数据的增删改查
1.linq创建之前，一定要在sql做好数据表的主外键关系。
2.linq文件是以.dbml结尾，一般一个数据库的名字就是一个linq的名字
3,以实例来演示增删改查
数据库的名字为linq，里面有两个表Users（UserName,Password,Sex,NickName,Birthday,Nation）和Nation(NationCode,NationName)
（1）创建名为linq的linq。
创建完之后啥也不用改，如果需要在重新封装类和数据扩展，那就想以前重新建立Users和UserData,只需要把需要重新封装和扩展的部分写上，在这之前一定要在总类面前加上Partial,如下
（2）继续封装类（注意partial）
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 { string a = "<空>"; if (_Sex != null) { a=Convert.ToBoolean(_Sex) ? "男" : "女"; } return a; } } public string NA { get { return this.Nation1.NationName; } } }
（3）建立方法（linq的增删改查方法）
using System; using System.Collections.Generic; using System.Linq; using System.Web; /// <summary> /// UsersDate 的摘要说明 /// </summary> public class UsersDate { linqDataContext cnn = null; public UsersDate() { cnn = new linqDataContext(); } /// <summary> /// 查询全部信息 /// </summary> /// <returns>泛型集合</returns> public List<Users> quan() { return cnn.Users.ToList();//如果没有数据，返回一个count=0的泛型集合 } /// <summary> /// 删除UserName=uname的整条数据 /// </summary> /// <param name="uname">名称</param> /// <returns>bool类型</returns> public bool delete(string uname) { bool a = false; Users u = cnn.Users.Where(r => r.UserName==uname).FirstOrDefault(); if (u != null) { cnn.Users.DeleteOnSubmit(u); cnn.SubmitChanges(); a = true; } return a; } /// <summary> /// 查询单条数据 /// </summary> /// <param name="uname">名字</param> /// <returns>对象</returns> public Users dan(string uname) { Users u = cnn.Users.Where(r => r.UserName == uname).FirstOrDefault(); return u; } /// <summary> /// 修改数据信息 /// </summary> /// <param name="u">需要改的内容</param> /// <returns>bool类型</returns> public bool update(Users u) { bool a = false; Users uu = cnn.Users.Where(r => r.UserName == u.UserName).FirstOrDefault(); if (uu != null) { uu.Password = u.Password; uu.NickName = u.NickName; uu.Sex = u.Sex; uu.Birthday = u.Birthday; uu.Nation = u.Nation; } try { cnn.SubmitChanges(); a = true; } catch { } return a; } /// <summary> /// 插入数据 /// </summary> /// <param name="u">对象</param> /// <returns>bool值</returns> public bool insert(Users u) { bool a = false; cnn.Users.InsertOnSubmit(u); try { cnn.SubmitChanges(); a = true; } catch { } return a; } }
（4）主界面和功能
<%@ 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"> <asp:Repeater ID="Repeater1" runat="server"> <HeaderTemplate> <table style="width:100%; text-align:center"> <tr style="background-color:blue;"> <td>姓名</td> <td>密码</td> <td>性别</td> <td>昵称</td> <td>生日</td> <td>民族</td> <td>操作</td> </tr> </HeaderTemplate> <ItemTemplate> <tr style="background-color:gray;"> <td><%#Eval("UserName") %></td> <td><%#Eval("Password") %></td> <td><%#Eval("SexStr") %></td> <td><%#Eval("NickName") %></td> <td><%#Eval("Birthday","{0:yyyy年MM月dd日}") %></td> <td><%#Eval("NA") %></td> <td> <a href=http://www.mamicode.com/"delete.aspx?uname=<%#Eval("UserName") %>">删除</a> <a href=http://www.mamicode.com/"update.aspx?uname=<%#Eval("UserName") %>" target="_blank">修改</a> </td> </tr> </ItemTemplate> <FooterTemplate> </table> </FooterTemplate> </asp:Repeater> <a href=http://www.mamicode.com/"insert.aspx" target="_blank">添加新数据</a> </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) { Repeater1.DataSource = new UsersDate().quan(); Repeater1.DataBind(); } } }
（5）删除界面的代码（删除界面不用布局，什么也没写）
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 uname=Request["uname"];//在delete.aspx页面接uanme bool a = new UsersDate().delete(uname); if (a) { Response.Write("<script>"); Response.Write("alert(‘删除成功‘);"); Response.Write("window.location.href=http://www.mamicode.com/‘Default.aspx‘;"); Response.Write("</script>"); } else { Response.Write("<script>"); Response.Write("alert(‘删除失败‘);"); Response.Write("window.location.href=http://www.mamicode.com/‘Default.aspx‘;"); Response.Write("</script>"); } } }
（6）插入界面的布局和代码
<%@ 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> </head> <body> <form id="form1" runat="server"> <div> 姓名<asp:TextBox ID="uname_Text" runat="server"></asp:TextBox> <asp:Label ID="unameerror_label" runat="server" Text=""></asp:Label><br /> 密码<asp:TextBox ID="pwd1_Text" runat="server" TextMode="Password"></asp:TextBox> <asp:Label ID="pwd1errpr_Label" runat="server" Text="Label"></asp:Label><br /> 确认密码<asp:TextBox ID="pwd2_Text" runat="server" TextMode="Password"></asp:TextBox><br /> 性别<asp:RadioButtonList ID="RadioButtonList1" runat="server" Width="106px" RepeatDirection="Horizontal"> <asp:ListItem Value=http://www.mamicode.com/"true" Selected="True">男</asp:ListItem> <asp:ListItem Value=http://www.mamicode.com/"false">女</asp:ListItem> </asp:RadioButtonList> 昵称<asp:TextBox ID="nickname_TextBox" runat="server"></asp:TextBox> <asp:Label ID="nicknameerror_Label" runat="server" Text="Label"></asp:Label><br /> 生日<asp:DropDownList ID="year_dd" runat="server" AutoPostBack="false"></asp:DropDownList> <asp:DropDownList ID="month_dd" runat="server" AutoPostBack="false"></asp:DropDownList> <asp:DropDownList ID="day_dd" runat="server" AutoPostBack="false"></asp:DropDownList><br /> 民族<asp:DropDownList ID="nation_dd" runat="server"></asp:DropDownList><br /> <asp:Button ID="enter" runat="server" Text="确定" /> </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 insert : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { for (int i = 2006; i >= 1990; i--) { year_dd.Items.Add(new ListItem(i.ToString(), i.ToString())); } for (int i = 12; i >= 1; i--) { month_dd.Items.Add(new ListItem(i.ToString(), i.ToString())); } for (int i = 31; i >= 1; i--) { day_dd.Items.Add(new ListItem(i.ToString(), i.ToString())); } nation_dd.DataSource = new NationData().quan(); nation_dd.DataTextField = "NationName"; nation_dd.DataValueField = "NationCode"; nation_dd.DataBind(); } enter.Click += enter_Click; } void enter_Click(object sender, EventArgs e) { Users uu = new Users(); Users u = new UsersDate().dan(uname_Text.Text); if (u != null) { unameerror_label.Text = "该用户名已被占用"; return; } unameerror_label.Text = ""; uu.UserName = uname_Text.Text; uu.Password = pwd1_Text.Text; uu.NickName = nickname_TextBox.Text; uu.Sex = Convert.ToBoolean(RadioButtonList1.SelectedValue); uu.Birthday = Convert.ToDateTime(year_dd.SelectedValue+"-"+month_dd.SelectedValue+"-"+day_dd.SelectedValue); uu.Nation = nation_dd.SelectedValue; bool a = new UsersDate().insert(uu); if (a) { Response.Write("<script>"); Response.Write("alert(‘插入成功‘);"); Response.Write("window.opener.location.href=http://www.mamicode.com/‘Default.aspx‘;"); Response.Write("window.close();"); Response.Write("</script>"); } else { Response.Write("<script>"); Response.Write("alert(‘插入失败‘);"); Response.Write("</script>"); } } }
（7）修改界面的布局和代码
<%@ 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> </head> <body> <form id="form1" runat="server"> <div> 姓名<asp:TextBox ID="uname_Text" runat="server"></asp:TextBox><br /> 密码<asp:TextBox ID="pwd1_Text" runat="server" TextMode="Password"></asp:TextBox> <asp:Label ID="pwd1errpr_Label" runat="server" Text="Label"></asp:Label><br /> 确认密码<asp:TextBox ID="pwd2_Text" runat="server" TextMode="Password"></asp:TextBox><br /> 性别<asp:RadioButtonList ID="RadioButtonList1" runat="server" Width="106px" RepeatDirection="Horizontal"> <asp:ListItem Value=http://www.mamicode.com/"true">男</asp:ListItem> <asp:ListItem Value=http://www.mamicode.com/"false">女</asp:ListItem> </asp:RadioButtonList> 昵称<asp:TextBox ID="nickname_TextBox" runat="server"></asp:TextBox> <asp:Label ID="nicknameerror_Label" runat="server" Text="Label"></asp:Label><br /> 生日<asp:DropDownList ID="year_dd" runat="server" AutoPostBack="false"></asp:DropDownList> <asp:DropDownList ID="month_dd" runat="server" AutoPostBack="false"></asp:DropDownList> <asp:DropDownList ID="day_dd" runat="server" AutoPostBack="false"></asp:DropDownList><br /> 民族<asp:DropDownList ID="nation_dd" runat="server"></asp:DropDownList><br /> <asp:Button ID="enter" runat="server" Text="确定" /> </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 update : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { Users u = new UsersDate().dan(Request["uname"]); if (u != null) { uname_Text.Text = u.UserName; if (u.Sex==null) { } else { if (u.Sex == true) { RadioButtonList1.Items[0].Selected = true; } else { RadioButtonList1.Items[1].Selected = true; } } nickname_TextBox.Text = u.NickName; for (int i = 2006; i >= 1990; i--) { year_dd.Items.Add(new ListItem(i.ToString(),i.ToString())); } for (int i = 12; i >= 1; i--) { month_dd.Items.Add(new ListItem(i.ToString(), i.ToString())); } for (int i = 31; i >= 1; i--) { day_dd.Items.Add(new ListItem(i.ToString(), i.ToString())); } nation_dd.DataSource = new NationData().quan(); nation_dd.DataTextField = "NationName"; nation_dd.DataValueField = "NationCode"; nation_dd.DataBind(); year_dd.SelectedValue = u.Birthday.Value.Year.ToString(); month_dd.SelectedValue = u.Birthday.Value.Month.ToString(); day_dd.SelectedValue = u.Birthday.Value.Day.ToString(); nation_dd.SelectedValue = u.Nation; } } enter.Click += enter_Click; } void enter_Click(object sender, EventArgs e) { Users u = new Users(); u.UserName = uname_Text.Text; u.Password = pwd1_Text.Text; u.NickName = nickname_TextBox.Text; u.Sex = Convert.ToBoolean(RadioButtonList1.SelectedValue); u.Birthday = Convert.ToDateTime(year_dd.SelectedValue+"-"+month_dd.SelectedValue+"-"+day_dd.SelectedValue); u.Nation = nation_dd.SelectedValue; bool a = new UsersDate().update(u); if (a) { Response.Write("<script>"); Response.Write("alert(‘修改成功‘);"); Response.Write("window.opener.location.href=http://www.mamicode.com/‘Default.aspx‘;"); Response.Write("window.close();"); Response.Write("</script>"); } else { Response.Write("<script>"); Response.Write("alert(‘修改失败‘);"); Response.Write("window.opener.location.href=http://www.mamicode.com/‘Default.aspx‘;"); Response.Write("window.close();"); Response.Write("</script>"); } } }
以上名称，密码或者其他的内容的格式没有做限制。特别是日期的三级联动也没做！
完！！
linq的创建 和 数据的增删改查
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