3月12日 增删改查

初始数据库

winform设计图

以面向对象的思想，先封装两个类：userDate类存属性，userDA类存方法

userDate类：

public class userDate     {         private int _code;

        public int Code                //封装类         {             get { return _code; }             set { _code = value; }         }         private string _uname;

        public string Uname         {             get { return _uname; }             set { _uname = value; }         }         private string _upass;

        public string Upass         {             get { return _upass; }             set { _upass = value; }         }     }

userDA类：

class userDA     {         private SqlConnection _Conn;         private SqlCommand _Cmd;

        public userDA()         {             _Conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");         }         //添加            public void Insert(userDate data)         {         }         //修改         public void Update(userDate data)         {         }         //删除         public void Delete(int code)         {         }         //查询全部         public List<userDate> Select2()         {          }         //按用户名查询         public List<userDate> Select2(string uname)         {          }     }

一、增加：

核心代码：

点击添加时：

private void button1_Click(object sender, EventArgs e)        {            userDate data = new userDate();

           data.Uname = textBox2.Text;            data.Upass = textBox1.Text;

           new userDA().Insert(data);        }

userDA类中：Insert方法

public void Insert(userDate data)         {             _Conn.Open();             _Cmd = _Conn.CreateCommand();             _Cmd.CommandText = "insert into table1 VALUES (@uname, @upass)";

            _Cmd.Parameters.Clear();             _Cmd.Parameters.Add("@uname",data.Uname);             _Cmd.Parameters.Add("@upass",data.Upass);             _Cmd.ExecuteNonQuery();             _Conn.Close();         }

1. 点增加                                            2.查询一下，添加上了

   

3.数据库里有了

二、查询：

核心代码：

点击查询时：

private void select2_Click(object sender, EventArgs e)         {            List<userDate> list= new userDA().Select2(textBox1.Text);             Binding(list);         }

//封装数据函数

private void Binding(List<userDate> list)        {            listView1.Columns.Clear();

           listView1.Columns.Add("编号");            listView1.Columns.Add("用户名");            listView1.Columns.Add("密码");

           listView1.Items.Clear();

           foreach (userDate date in list)            {                ListViewItem lt = new ListViewItem();                lt.Text = date.Code.ToString();                lt.SubItems.Add(date.Uname);                lt.SubItems.Add(date.Upass);

               listView1.Items.Add(lt);            }        }

userDA类中：两个查询函数（重载）

     //查询全部        public List<userDate> Select2()        {            List<userDate> list=new List<userDate>();

           _Conn.Open();            _Cmd = _Conn.CreateCommand();            _Cmd.CommandText = "select*from table1";

           SqlDataReader dr = _Cmd.ExecuteReader();

           while (dr.Read())            {                userDate data = new userDate();                data.Code = int.Parse(dr["code"].ToString());                data.Uname = dr["uname"].ToString();                data.Upass = dr["upass"].ToString();

               list.Add(data);            }

            return list;        }        //按用户名查询（条件查询）        public List<userDate> Select2(string uname)        {            List<userDate> list = new List<userDate>();

           _Conn.Open();            _Cmd = _Conn.CreateCommand();            _Cmd.CommandText = "select * from table1 where uname like '%"+uname+"%'";

           SqlDataReader dr = _Cmd.ExecuteReader();

           while (dr.Read())            {                userDate data = new userDate();                data.Code = int.Parse(dr["code"].ToString());                data.Uname = dr["uname"].ToString();                data.Upass = dr["upass"].ToString();

               list.Add(data);            }

           return list;        }

1.全部显示：                                           2.按用户名模糊查询

      

 

三、修改

核心代码：

点击时：

private void button1_Click(object sender, EventArgs e)        {            userDate data = new userDate();

           data.Code = int.Parse(textBox3.Text);            data.Uname = textBox2.Text;            data.Upass = textBox1.Text;

           new userDA().Update(data);        }

userDA类中：

public void Update(userDate data)     {         _Conn.Open();         _Cmd = _Conn.CreateCommand();         _Cmd.CommandText = "update table1 set uname='"+data.Uname+"',upass='"+data.Upass+"' where code="+data.Code;

        _Cmd.ExecuteNonQuery();         _Conn.Close();     }

1.点击修改                                         2.查询后改变了                                 3。数据库也变了

       

 

四、删除

核心代码：

点击时：

private void delete1_Click(object sender, EventArgs e)        {            if (listView1.SelectedItems.Count > 0)  // SelectedItems选中项            {                int code = int.Parse(listView1.SelectedItems[0].Text);                new userDA().Delete(code);            }            else            {                MessageBox.Show("请先选中，再删除！");            }            List<userDate> list = new userDA().Select2();            Binding(list);        }

userDA类：

public void Delete(int code)         {             _Conn.Open();             _Cmd = _Conn.CreateCommand();             _Cmd.CommandText = "delete from table1 where code="+code;

            _Cmd.ExecuteNonQuery();

            _Conn.Close();         }

1.点击删除时：                                     2.点击删除后：

        

转载于:https://www.cnblogs.com/tzq9308/p/4332924.html