面向对象——数据库增删改查2015年6月2日22:11:52

 public class method

    {   //成员变量

        private SqlConnection conn; 

        private SqlCommand cmd;

        public method() //通过构造函数给变量赋值

        {

            conn = new SqlConnection("server=.;database=Linkdatabase;user=sa;pwd=123");

            cmd = conn.CreateCommand();

        }

        public List<bianliang> Select() //全部查询

        {

            List<bianliang> list = null; //泛型集合，包含集合的集合

            conn.Open();

            cmd.CommandText = "select * from wwz";

            SqlDataReader dr=cmd.ExecuteReader();

            if(dr.HasRows) //如果反馈的dr里面有值，才会执行下面的代码

            {

                list = new List<bianliang>(); //创建一个新的泛型集合

                while (dr.Read()) //只要返回的结果为true dr.read()即为true

                {   

                    //将数据一条条增加到集合中

                    bianliang s = new bianliang(); 

                    s.Code = dr["Code"].ToString();

                    s.Name = dr["Name"].ToString();

                    s.Class = dr["Class"].ToString();

                    s.Score = dr["Score"].ToString();

                    list.Add(s);

                }

            }

            return list;    

        }

      }

  private void button1_Click(object sender, EventArgs e) //全部查询

        {

           List<bianliang>  x= new method().Select(); //调用函数 将结果反馈给x

           listView1.Items.Clear();//将原来listview1表的内容清空一下

           for (int i = 0; i < x.Count; i++) //一次次将获得的数据显示在listview1中

           {

               listView1.Items.Add(x[i].Code); //items代表的是行

               listView1.Items[i].SubItems.Add(x[i].Name); //Items[i].SubItems代表的是Items这一行剩下的内容

               listView1.Items[i].SubItems.Add(x[i].Class);

               listView1.Items[i].SubItems.Add(x[i].Score);

           }

        }

 public bianliang Select(string code)  //根据编号查询(条件查询)，是为了以后的修改用的(加载页面时)

        {

            bianliang s = null;

            conn.Open();

            cmd.CommandText = "select * from wwz where Code="+code+"";

            SqlDataReader dr = cmd.ExecuteReader();

            if (dr.HasRows) //如果反馈的dr里面有值，才会执行下面的代码

            {    

                if (dr.Read()) //只要返回的结果为true才会执行下面的代码。 dr.read()即为true

                { 

                    s = new bianliang();

                    s.Code = dr["Code"].ToString();

                    s.Name = dr["Name"].ToString();

                    s.Class = dr["Class"].ToString();

                    s.Score = dr["Score"].ToString();             

                }

            }

            return s;

        }



        public List<bianliang> Select(string x,string y) //模糊查询(条件查询)

        {

            List<bianliang> list = null; //泛型集合，包含集合的集合

            conn.Open();

            cmd.CommandText = "select * from wwz where Class like '%"+x+"%' and Score like '%"+y+"%' ";

            SqlDataReader dr = cmd.ExecuteReader();

            if (dr.HasRows) //如果反馈的dr里面有值，才会执行下面的代码

            {

                list = new List<bianliang>(); //创建一个新的泛型集合

                while (dr.Read()) //只要返回的结果为true dr.read()即为true

                {

                    //将数据一条条增加到集合中

                    bianliang s = new bianliang();

                    s.Code = dr["Code"].ToString();

                    s.Name = dr["Name"].ToString();

                    s.Class = dr["Class"].ToString();

                    s.Score = dr["Score"].ToString();

                    list.Add(s);

                }

            }

            return list;

        }

 

  public void Insert(bianliang z) //增加

        {

            conn.Open();

            cmd.CommandText = "insert into wwz values(@code,@name,@class,@score)"; //@code 代位符

            cmd.Parameters.Clear();//清空原来代位符的内容

            cmd.Parameters.Add("@code",z.Code);//给代位符赋值

            cmd.Parameters.Add("@name",z.Name);

            cmd.Parameters.Add("@class",z.Class);

            cmd.Parameters.Add("@score",z.Score);

            cmd.ExecuteNonQuery();

            cmd.Dispose();

            conn.Close();

        }



 private void button1_Click(object sender, EventArgs e) //增加

        {

            if (textBox1.Text != null && textBox2.Text != null&&textBox3.Text != null&&textBox4.Text != null)

            {

            bianliang x = new bianliang();

            x.Code = textBox1.Text;

            x.Name = textBox2.Text;

            x.Class = textBox3.Text;

            x.Score = textBox4.Text;

            new method().Insert(x);

            MessageBox.Show("增加成功");

            }

        }

  private void button3_Click(object sender, EventArgs e) //增加

        {   

            add f = new add();

            f.Show();

        }

 

 

 

 

 

 

 

  public void Update(bianliang x) //修改

        {

            conn.Open();

            cmd.CommandText = "update wwz set Name='"+x.Name+"', Class='"+x.Class+"',Score='"+x.Score+"' where Code="+x.Code+"";

            cmd.ExecuteNonQuery();

            cmd.Dispose();

            conn.Close();

        }

public partial class update : Form

    {

        private string S;

        public update(string s)

        {

            InitializeComponent();

            S = s;

        }



        private void update_Load(object sender, EventArgs e) //加载页面时

        {

            bianliang load = new method().Select(S); //将调用Select(string s)函数后获取到的结果放在load里

            textBox1.Text =load.Code;

            textBox2.Text =load.Name;

            textBox3.Text = load.Class;

            textBox4.Text = load.Score;

        }



        private void button1_Click(object sender, EventArgs e) //点击修改窗体上的修改按钮

        {  //创建一个变量，将文本框内的值放在这个变量中

            bianliang update = new bianliang();  

            update.Code = textBox1.Text;

            update.Name = textBox2.Text; 

            update.Class = textBox3.Text;

            update.Score = textBox4.Text;

            new method().Update(update);

            MessageBox.Show("修改成功");   



        }

    }

private void button5_Click(object sender, EventArgs e)//修改
{

if(listView1.SelectedItems.Count>0)
{
string s = listView1.SelectedItems[0].Text;
update f = new update(s);
f.Show();
}
}

 

 

 

  public void Delete(string code) //删除

        {

            conn.Open();

            cmd.CommandText = "delete from wwz where code="+code+"";

            cmd.ExecuteNonQuery();

            cmd.Dispose();

            conn.Close();

        }



 private void button4_Click(object sender, EventArgs e) //删除

        {

            if(listView1.SelectedItems.Count>0)

            {

            string code = listView1.SelectedItems[0].Text;

            new method().Delete(code);

            //执行完删除后再执行一次全部查询

            List<bianliang> x = new method().Select(); //调用函数 将结果反馈给x

            listView1.Items.Clear();//将原来listview1表的内容清空一下

            for (int i = 0; i < x.Count; i++) //一次次将获得的数据显示在listview1中

            {

                listView1.Items.Add(x[i].Code); //items代表的是行

                listView1.Items[i].SubItems.Add(x[i].Name); //Items[i].SubItems代表的是Items这一行剩下的内容

                listView1.Items[i].SubItems.Add(x[i].Class);

                listView1.Items[i].SubItems.Add(x[i].Score);

            }

            }

        }