C#

 private void comboBox3_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {

                database = new OleDbConnection(connectionString);

                // Create a command object and then a query which accepts a papameter
                System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand("Select distinct ProductName from Products", database);
                database.Open();
                System.Data.OleDb.OleDbDataReader dr;
                dr = cmd.ExecuteReader();

                while (dr.Read())
                {
                    //comboBox3.Items.AddRange(new object[] { dr[1].ToString() });  //Change the index according to the values you want to populate in the combobox.
                    comboBox3.Items.AddRange(new Object[] { dr[1].ToString() });
                    
                }
                dr.Close();
            }
            catch (Exception ex)
            {

                MessageBox.Show(ex.Message);
                return;
            }
}

Wheels012 wrote:

It is actually in a method:

str=dgrid[colIndex,rowIndex].FormattedValue.ToString();