运用.NIT将数据存入数据库、读取数据库（运用封装）陈老师作业

我基础不好，根据所学的知识，书本的例题修改的，也不知道我理解的是否符合老师要求

运用C#将数据存入数据库、并且可以读取数据库里的数据，此项目我运用了封装。我运用了一个窗体将数据存读数据。

我首先创建了一个数据库，库名“数学题库” ，然后创建了一个表“tiku1”,

添加一个类Class1

class Class1
    {
        public string strCon = @"Data Source=.;Initial Catalog=数学题库;Integrated security=true";
        public SqlConnection sqlcon = new SqlConnection();
        public SqlDataAdapter sda = new SqlDataAdapter();
        public DataSet ds = new DataSet();
        public DataTable dt = new DataTable();
        public SqlDataReader sdr;
        public void suanshu()
        {
            try
            {
                sqlcon = new SqlConnection(strCon);
            }
            catch (Exception e)
            {
                MessageBox.Show("数据库连接不成功：" + e.ToString());
            }
        }
        public void suanFill(string selstr)
        {
            dt.Clear();
            sda = new SqlDataAdapter(selstr, strCon);
            sda.Fill(ds,"tiku1");
            dt = ds.Tables["tiku1"];
        }
        public void suanselect(string showtnfo)
        {
            sqlcon.Open();
            SqlCommand sqlcmd = new SqlCommand(showtnfo, sqlcon);
            sdr = sqlcmd.ExecuteReader();
        }
        public void suanInsert(string insertinfo)
        {
            sqlcon.Open();
            SqlCommand sqlcmd = new SqlCommand(insertinfo, sqlcon);
            try
            {
                sqlcmd.ExecuteNonQuery();
            }
            catch (Exception e)
            {
                MessageBox.Show("数据插入失败：" + e.ToString());
            }
            sqlcon.Close();
        }
        public void suanGridViewUpd()
        {
            SqlCommandBuilder scb = new SqlCommandBuilder(sda);
            DialogResult result;
            result = MessageBox.Show("确定保存修改过的数据吗？", "操作提示", MessageBoxButtons.OKCancel, MessageBoxIcon.Question);
            if (result == DialogResult.OK)
            {
                dt = ds.Tables["tuku1"];
                sda.Update(dt);
                dt.AcceptChanges();
            }
        }
        public void suanDelete(string delStr)
        {
            sqlcon.Open();
            SqlCommand sqlcmd = new SqlCommand(delStr, sqlcon);
            try
            {
                sqlcmd.ExecuteNonQuery();
                MessageBox.Show("数据删除成功！");
            }
            catch (Exception ex)
            {
                MessageBox.Show("数据删除失败" + ex.ToString());
            }
            sqlcon.Close();
        }
    }
}

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        string selstr = @"select * from tiku1 ";
        Class1 db = new Class1();

private void Form1_Load(object sender, EventArgs e)
        {
            db.suanshu();
            db.suanFill(selstr);
            comboBox1.ValueMember = "序号";
            comboBox1.DataSource = db.dt.DefaultView;
        }

private void button4_Click(object sender, EventArgs e)
        {
            db.suanshu();
            db.suanFill(selstr);
            dataGridView1.DataSource = db.dt;
        }

private void button1_Click(object sender, EventArgs e)
        {
            db.suanshu();
            string insertinfo = "insert into tiku1(序号,第一个数,符号一,第二个数,符号二,第三个数,符号三,结果) values('" + comboBox1.Text + "','" + textBox1.Text +
            "','" + textBox2.Text +
            "','" + textBox3.Text + "','" + textBox4.Text + "','" + textBox5.Text + "','" + textBox6.Text +
            "','" + textBox7.Text +
            "')";
            db.suanInsert(insertinfo);
            db.suanFill(selstr);
            dataGridView1.DataSource = db.dt;
        }

private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            string selinfo = "select 第一个数,符号一,第二个数,符号二,第三个数,符号三,结果 from tiku1 where 序号='" + comboBox1.Text.ToString().Trim() + "'";
            db.suanshu();
            db.suanselect(selinfo);
            while (db.sdr.Read())

{

textBox1.Text = db.sdr["第一个数"].ToString();

textBox2.Text = db.sdr["符号一"].ToString();

textBox3.Text = db.sdr["第二个数"].ToString();

textBox4.Text = db.sdr["符号二"].ToString();

textBox5.Text = db.sdr["第三个数"].ToString();

textBox6.Text = db.sdr["符号三"].ToString();

textBox7.Text = db.sdr["结果"].ToString();

}

db.sdr.Close();
        }

private void button3_Click(object sender, EventArgs e)
        {
            db.suanshu();
            string strupd = "delete from tiku1 where 序号='" + comboBox1.Text.Trim() + "'";
            db.suanDelete(strupd);
          
            db.suanFill(selstr);
            dataGridView1.DataSource = db.dt;
        }

private void button2_Click(object sender, EventArgs e)
        {
            db.suanshu();
            db.suanGridViewUpd();
        }

}

}

说明

每道题我都编辑了序号，可以根据序号选题，改题，（序号我设置了下拉列表）

1、点击查询可以查询数据库里表里数据

2、点击添加可以添加数据

3、删除数据，更新数据