DugunSalonu/FrmLogin.cs

using DugunSalonu.Models;
using Microsoft.EntityFrameworkCore;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Buffers;

namespace DugunSalonu
{
    public partial class FrmLogin : Form
    {
        public FrmLogin()
        {
            InitializeComponent();
        }

        private void FrmLogin_Load(object sender, EventArgs e)
        {

        }

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

        private async void btnGiris_Click(object sender, EventArgs e)
        {
            try
            {
                using (dugunsalonuContext db = new dugunsalonuContext())
                {
                    var user = await db.kullanici.Where(k => k.KullaniciAdi == txtKullanici.Text && k.Aktif == true && k.Parola == txtSifre.Text).FirstOrDefaultAsync();
                    if (user != null)
                    {
                        FrmAddKullanici f1 = new FrmAddKullanici();
                        f1.Show();
                        this.Hide();
                    }
                    else { MessageBox.Show("Hatalý kullanýcý bilgileri.","Hata"); }
                    //Kullanici girisKullanicisi = await db.Kullanici.Where(k => k.KullaniciAdi == txtKullanici.Text && k.Parola == txtSifre.Text).FirstOrDefaultAsync();
                }
            }
            catch (Exception)
            {

                throw;
            }
        }
    }
}