InfoTracks/InfoTrack/FormAutorization.cs

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

namespace InfoTrack
{
    public partial class FormAutorization : Form
    {
        DataBase dataBase = new DataBase();

        public FormAutorization()
        {
            InitializeComponent();
            StartPosition = FormStartPosition.CenterScreen;
        }

        private void buttonEnter_Click(object sender, EventArgs e)
        {
            SqlDataAdapter adapter = new SqlDataAdapter();
            DataTable table = new DataTable();

            var login = textBoxForLogin.Text;
            var password = textBoxForPass.Text;

            if (login == "логин")
            {
                MessageBox.Show("Введите логин");
                return;
            }
            if (password == "пароль")
            {
                MessageBox.Show("Введите пароль");
                return;
            }

            string zapros = $"select Login from Users where Login = '{login}' and Password = '{password}'";

            SqlCommand command = new SqlCommand(zapros, dataBase.getConnection());

            adapter.SelectCommand = command;
            adapter.Fill(table);

            if (table.Rows.Count == 1)
            {
                GlobalValues.login = login;
                this.Hide();
                FormMenu form = new FormMenu();
                form.Show();
            }
            else
            {
                MessageBox.Show("Неверный логин или пароль");
            }
        }

        private void textBoxForLogin_TextChanged(object sender, EventArgs e)
        {
            if (textBoxForLogin.Text == "логин")
            {

                textBoxForLogin.Text = "";

            }

            if (textBoxForPass.Text == "")
            {

                textBoxForPass.UseSystemPasswordChar = false;
                textBoxForPass.Text = "пароль";
            }
        }

        private void textBoxForPass_TextChanged(object sender, EventArgs e)
        {

            if (textBoxForPass.Text == "пароль")
            {
                textBoxForPass.Text = "";

                textBoxForPass.UseSystemPasswordChar = true;
            }

            if (textBoxForLogin.Text == "")
            {

                textBoxForLogin.Text = "логин";
            }
        }

        private void labelForExit_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}