using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace LinqToSqlFrom1 { using DBSpace; using System.Data.Linq; public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { DBConn conn = new DBConn("database=Jiang;User ID = Jiang;pwd=admin;server=JIANG-PC\\SQL2010"); var user = from u in conn.CreateUser where u.Uid < 3 orderby u.Uid select u; foreach (var v in user) this.listBox1.Items.Add(v.Name.ToString()); } private void listBox1_SelectedIndexChanged(object sender, EventArgs e) { this.listBox2.Items.Clear(); DBConn conn = new DBConn("database=Jiang;User ID = Jiang;pwd=admin;server=JIANG-PC\\SQL2010"); var users = from u in conn.CreateUser from us in u.Userid where u.Name == this.listBox1.SelectedItem.ToString() select us; foreach (var v in users) this.listBox2.Items.Add(v.UserName.ToString()); } } } namespace DBSpace { using System.Data.Linq; using System.Data.Linq.Mapping; public class DBConn : DataContext { public Table<CDB_MEMBERS> CreateUser; public DBConn(string connectionstring) : base(connectionstring) { } public DBConn(IDbConnection connectionstring) : base(connectionstring) { } } [Table(Name = "cdb_members")] public class CDB_MEMBERS { [Column(IsPrimaryKey = true)] public int Uid; [Column] public string Name; [Column] public string Pass; private EntitySet<CDB_MEMBERSINFO> userid; [Association(Storage = "userid", OtherKey = "Uid")] public EntitySet<CDB_MEMBERSINFO> Userid { get { return this.userid; } set { this.userid.Assign(value); } } [Table(Name = "cdb_membersinfo")] public class CDB_MEMBERSINFO { [Column(IsPrimaryKey = true)] public int Fid; [Column] public string UserName; [Column] public string Sex; [Column] public string Age; [Column] public string Address; [Column] public string Tel; [Column] public string Phone; [Column] public int Uid; private EntityRef<CDB_MEMBERS> uid; [Association(Storage = "uid", ThisKey = "Uid")] public CDB_MEMBERS Members { get { return this.uid.Entity; } set { this.uid.Entity = value; } } } } }