How to Populate DataGridView Combobox C#.net

This tutorial will teach you how to Populate DataGridView based on Combobox selected using C#.net and Microsoft SqlServer.

Import the Namespace

using System.Data.SqlClient;

Establish the database Connection

SqlConnection con = new SqlConnection("server=.;database=ads;user id=sa;password=123;");
SqlCommand cmd;
SqlDataAdapter dr;
DataSet ds;

ComboBox Selected Event

        if (comboBox1.SelectedItem.ToString() == "Students")
            {
                try
                {
                    dataGridView1.Refresh();
                    con.Open();
                    DataTable dt = new DataTable();
                    dr = new SqlDataAdapter("select * from student", con);
                    dr.Fill(dt);
                    dataGridView1.DataSource = dt;
                    con.Close();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }

            }
            else if (comboBox1.SelectedItem.ToString() == "Courses")
            {
                try
                {
                    dataGridView1.Refresh();
                    con.Open();
                    DataTable dt = new DataTable();
                    dr = new SqlDataAdapter("select * from course", con);
                    dr.Fill(dt);
                    dataGridView1.DataSource = dt;
                    con.Close();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }