Important!!! entity classes, data access classes

Create a two class:

Users Category:

Using system;using system.collections.generic;using system.linq;using System.text;namespace entity Class _ Data Access class.        app_code{public class Users {private int _ids; <summary>//IDs//</summary> public int IDs {get {return _ids ;        } set {_ids = value;}        } private string _username; <summary>///user name///</summary> public string UserName {get {ret Urn _username;        } set {_username = value;}        } private string _password; <summary>//password///</summary> public string PassWord {get {Retu RN _password;        } set {_password = value;}        } private string _nickname; <summary>//Nickname///</summary> public string Nickname {get {Retu RN _nickname; } set {_nickname = ValUe        }} private bool _sex; <summary>///gender///</summary> public bool Sex {get {return _sex ;        } set {_sex = value;}        } private DateTime _birthday; <summary>//Birthdays///</summary> public DateTime Birthday {get {RE Turn _birthday;        } set {_birthday = value;}        } private string _nation;  <summary>//National///</summary> public string Nation {get {return} _nation;        } set {_nation = value;}        } private string _class; <summary>///class///</summary> public string class {get {return _class;        } set {_class = value;} }    }}

Usersdata:

Using system;using system.collections.generic;using system.linq;using system.text;using System.Data.SqlClient; Namespace entity class _ Data Access class.        app_code{public class Usersdata {SqlConnection conn = null;        SqlCommand cmd = null; Public Usersdata () {conn = new SqlConnection ("server=.;            Database=data0928;user=sa;pwd=123 "); CMD = conn.        CreateCommand (); }///<summary>///Add data to the Users table, return True to add success///</summary>//<param name= "        U "> Users object to add to datasheet </param>//<returns></returns> public bool Insert (Users u)            {bool OK = false;            int count = 0;            Cmd.commandtext = "INSERT into Users values (@a,@b,@c,@d,@e,@f,@g)"; Cmd.            Parameters.clear (); Cmd.            Parameters.addwithvalue ("@a", u.username); Cmd.            Parameters.addwithvalue ("@b", U.password); Cmd.            Parameters.addwithvalue ("@c", u.nickname); CmD.parameters.addwithvalue ("@d", u.sex); Cmd.            Parameters.addwithvalue ("@e", u.birthday); Cmd.            Parameters.addwithvalue ("@f", u.nation); Cmd.            Parameters.addwithvalue ("@g", U.class); try {Conn.                Open (); Count = cmd.            ExecuteNonQuery ();            } catch {ok = false;} finally {Conn.            Close ();            } if (Count > 0) ok = true;        return OK; }//Querying all data in database tables public list<users> Select () {list<users> List = new List<u            Sers> ();            Cmd.commandtext = "Select *from Users"; Conn.            Open (); SqlDataReader dr = cmd.            ExecuteReader (); if (Dr. HasRows) {while (Dr.                    Read ()) {Users u = new Users ();                    U.ids = Convert.ToInt32 (dr["Ids"]); U.username = dr["UsErname "].                    ToString (); U.password = dr["PassWord"].                    ToString (); U.nickname = dr["nickname"].                    ToString ();                    U.sex = Convert.toboolean (dr["Sex"]);                    U.birthday = Convert.todatetime (dr["Birthday"]); U.nation = dr["Nation"].                    ToString (); U.class = dr["Class"].                    ToString (); List.                ADD (U); }} conn.            Close ();        return list;            }//Query the data for the specified user name bool Select (string username) {bool ok = false;            Cmd.commandtext = "Select *from Users where UserName = @a"; Cmd.            Parameters.clear (); Cmd.            Parameters.Add ("@a", username);            Users u = new users (); Conn.            Open (); SqlDataReader dr = cmd.            ExecuteReader (); if (Dr. HasRows) {while (Dr. Read ()) {u.ids = Convert.toInt32 (dr["IDs"]); U.username = dr["UserName"].                    ToString (); U.password = dr["PassWord"].                    ToString (); U.nickname = dr["nickname"].                    ToString ();                    U.sex = Convert.toboolean (dr["Sex"]);                    U.birthday = Convert.todatetime (dr["Birthday"]); U.nation = dr["Nation"].                    ToString (); U.class = dr["Class"].                    ToString ();                OK = true; }} conn.            Close ();        return OK; }//delete data public void Delete (string uname) {cmd.            CommandText = "Delete from Users where UserName = @a"; Cmd.            Parameters.clear (); Cmd.            Parameters.Add ("@a", uname); Conn.            Open (); Cmd.            ExecuteNonQuery (); Conn.        Close (); }    }}

The method is called in the main function:

Using system;using system.collections.generic;using system.linq;using system.text;using entity Class _ Data Access class. App_code;namespace entity Class _ Data Access class {class program {static void Main (string[] args) {//list<u            Sers> ulist=new list<users>;            UserData da=new UserData ();            Ulist=da.select (); list<users> ulist = new Usersdata ().            Select (); foreach (Users uuu in Ulist) {Console.WriteLine (UUU. Ids + "" + UUU. UserName + "" + UUU. PassWord + "" + UUU. Nickname + "" + UUU. Sex + "" + UUU. Birthday + "" + UUU. Nation + "" + UUU.            Class);            } console.write ("Please enter the user name to delete:");            String uname = Console.ReadLine (); if (new Usersdata (). Select (uname)) {Console.WriteLine ("This user information has been found, do you want to delete it?")                (y/n) ");                String yn = Console.ReadLine (); if (yn. ToUpper () = = "Y") {new Usersdata (). DelEte (uname); Console.WriteLine ("Delete succeeded!                ");            }} The users user = new users ();            Console.Write ("Please enter user name:"); User.            UserName = Console.ReadLine ();            Console.Write ("Please enter password:"); User.            PassWord = Console.ReadLine ();            Console.Write ("Please enter a nickname:"); User.            Nickname = Console.ReadLine ();            Console.Write ("Please enter Gender:"); User.            Sex = Convert.toboolean (Console.ReadLine ());            Console.Write ("Please enter your Birthday:"); User.            Birthday = Convert.todatetime (Console.ReadLine ());            Console.Write ("Please enter the Nation:"); User.            Nation = Console.ReadLine ();            Console.Write ("Please enter class:"); User.            Class = Console.ReadLine ();            Usersdata ud = new Usersdata (); BOOL isOK = UD.            Insert (user); if (isOK) Console.WriteLine ("Add success!            "); else Console.WriteLine ("Add failed!            ");        Console.readkey (); }    }}

Important!!! entity classes, data access classes