[置顶] 最近研究了下接口，对interface的有关总结

C#中定义接口：

    public interface Sk_usersCL
    {
        int Uid { get;}
        string UserName { set;get;}
        string PassWord { set;get;}
        string Sex { set;get;}
        string Connectionstring { set;get;}
        int InsusersCL();
        int GetdatausersCl();

    }

实现接口的类：

public class sk_usersclsCL : Sk_usersCL
    {
        private int puid;
        private string pusername;
        private string ppassword;
        private string psex;
        private string pconnectionstring;
        private SqlConnection conn;

        public int Uid
        {
            get { return puid; }
        }
        public string UserName
        {
            set { pusername = value; }
            get { return pusername; }
        }
        public string PassWord
        {
            set { ppassword = value; }
            get { return ppassword; }
        }
        public string Sex
        {
            set { psex = value; }
            get { return psex; }
        }
        public string Connectionstring
        {
            set { pconnectionstring = value; }
            get { return pconnectionstring; }
        }
        public void Open()
        {
            conn = new SqlConnection(pconnectionstring);
            if (conn.State == System.Data.ConnectionState.Closed)
            {
                conn.Open();
            }
        }
        public void Close()
        {
            if (conn.State == System.Data.ConnectionState.Open)
            {
                conn.Close();
            }
        }
        public int InsusersCL()
        {
            Open();
            string strinssql = "insert into users (user_name,pwd,sex) values('"+UserName+"','"+PassWord+"','"+Sex+"')";
            SqlCommand cmd = new SqlCommand(strinssql, conn);
            int intnum = cmd.ExecuteNonQuery();
            Close();
            return intnum;
        }

        public int UpdusersCL()
        {
            Open();
            string strupdsql = "update users set pwd='"+PassWord+"' where user_name='"+UserName+"'";
            SqlCommand cmd = new SqlCommand(strupdsql,conn);
            int rcount = cmd.ExecuteNonQuery();
            Close();
            return rcount;
        }
创建一个逻辑层：

        //创建接口
        Sk_usersCL.Sk_usersCL userCL;
        #region 定义属性，
        private int puid;
        private string pusername;
        private string ppassword;
        private string psex;
        private string pconnstr;
        public int Uid
        {
            get { return puid; }
            set { puid = value; }
        }
        public string UserName
        {
            get { return pusername; }
            set { pusername = value; }
        }
        public string PassWord
        {
            get { return ppassword; }
            set { ppassword = value; }
        }
        public string Sex
        {
            get { return psex; }
            set { psex = value; }
        }
        public string Connectionstring
        {
            get { return pconnstr; }
            set { pconnstr = value; }
        }
        #endregion
        public string GetConnstr()
        {
            return "server=Data-11;User id=11; Pwd=11;database=11";
        }
        public int insusers()
        {
            sk_usersclsCL users = new sk_usersclsCL();
            userCL = users;
            userCL.UserName = pusername;
            userCL.PassWord = ppassword;
            userCL.Sex = psex;
            userCL.Connectionstring = GetConnstr();
            return userCL.InsusersCL();
        }
       
        public int Updusers()
        {
            sk_usersclsCL users = new sk_usersclsCL();//创建数据层的对象
            userCL = users;  //赋值给接口对象，接口调用继承该接口的类
            userCL.UserName = pusername;
            userCL.PassWord = ppassword;
            userCL.Sex = psex;
            userCL.Connectionstring = GetConnstr();
            return userCL.UpdusersCL();
        }
    }

表现层调用逻辑层：

        Sk_usersBL.Class1 us = new Sk_usersBL.Class1();  //声明逻辑层的对象
        us.UserName = TBusername.Text;
        us.PassWord = TBpassword.Text;
        if (us.Updusers() > 0)
        {
            Response.Write("<script language=javascript>alert('修改成功！')</script>");
        }
        else
        {
            Response.Write("<script language=javascript>alert('修改失败！')</script>");
        }