将在combobox中选择的数据检索到datagridview

Question

我如何检索在组合框中选择的数据并从数据库中检索该数据的信息到datagridview

Answer 1

using System;
using System.Data;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace WindowsFormsApplication12
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        SqlConnection cn = new SqlConnection("data source=localhost;initial catalog=acc;uid=sa;pwd=emotions");
        private void Form1_Load(object sender, EventArgs e)
        {
            SqlDataAdapter da = new SqlDataAdapter("select ClassId, Class from Class order by ClassId", cn);
            DataTable dt = new DataTable();            
            da.Fill(dt);
            comboBox1.DataSource = dt;
            comboBox1.DisplayMember = "Class";
            comboBox1.ValueMember = "ClassId";
        }
        private void comboBox1_SelectionChangeCommitted(object sender, EventArgs e)
        {
            SqlDataAdapter da = new SqlDataAdapter("select SNAme, FName, SPhoneNo from Students where ClassId =" + comboBox1.SelectedValue, cn);
            DataTable dt = new DataTable();
            da.Fill(dt);
            dataGridView1.DataSource = dt;
        }
    }
}