using System.Data.SqlClient; SqlConnection conn; //连接数据库 private void Form1_Load(object sender, EventArgs e) { string constr = "server=ACER-PC\\LI;database=db_test;uid=sa;pwd=123"; conn = new SqlConnection(constr); //数据库连接 }
查询：
//这里只要连接数据库即可，不必打开数据库 private void button1_Click(object sender, EventArgs e) { SqlCommand cmd = new SqlCommand("select * from tb_ls", conn); SqlDataAdapter sda = new SqlDataAdapter(); sda.SelectCommand = cmd; DataSet ds = new DataSet(); sda.Fill(ds, "cs"); dataGridView1.DataSource = ds.Tables[0]; }
删除：
private void button2_Click(object sender, EventArgs e) { if (this.dataGridView1.SelectedRows.Count > 0) { DataRowView drv = dataGridView1.SelectedRows[0].DataBoundItem as DataRowView; drv.Delete(); } conn.Open();//打开数据库 SqlCommand cmd = new SqlCommand("delete from tb_ls where 编号="+this.dataGridView1.CurrentRow.Cells["编号"].Value+"",conn); cmd.ExecuteNonQuery(); conn.Close();//关闭数据库 }
添加：
private void button3_Click(object sender, EventArgs e) { conn.Open(); SqlCommand cmd = new SqlCommand("insert into tb_ls values('"+textBox1.Text+"','"+textBox2.Text+"','"+textBox3.Text+"','"+textBox4.Text+"')",conn); cmd.ExecuteNonQuery(); conn.Close(); }
更新:
private void button4_Click(object sender, EventArgs e) { conn.Open(); SqlCommand cmd = new SqlCommand("update tb_ls set 姓名='"+textBox2.Text+"',性别='"+textBox3.Text+"',年龄='"+textBox4.Text+"' where 编号='"+textBox1.Text+"'",conn); textBox1.ReadOnly = false; cmd.ExecuteNonQuery(); conn.Close(); }