ghhfgh/Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        SqlConnection connection;
        SqlCommand command;
        SqlDataAdapter adapter;
        DataTable table;
        public Form1()
        {
            InitializeComponent();
            connection = new SqlConnection("Server=Class31000;Database=aero;Trusted_connection=true;");
            command = new SqlCommand();
            command.Connection = connection;
            command.CommandType = CommandType.Text;
            adapter = new SqlDataAdapter(command);
            table = new DataTable();
        }

private void ShowTable(string text)
        {
            dataGridView1.Columns.Clear();
            dataGridView1.DataSource = null;
            command.CommandText = text;
            table.Clear();
            adapter.Fill(table);
            dataGridView1.DataSource = table;
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            ShowTable("Select * From Users");
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form2 b = new Form2();
            b.Show();
            this.Hide();
        }
    }
}