Untitled

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


namespace WindowsFormsApplication1
{
    public partial class frmLogin : Form
    {
        public frmLogin()
        {
            InitializeComponent();
        }

        public static string usuarioConectado;
        public static string nivelAcesso;

        private void frmLogin_Load(object sender, EventArgs e)
        {

           
        }

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

        private void btnConectar_Click(object sender, EventArgs e)
        {
            /* ligação a base de dados*/
            SqlConnection cn = new SqlConnection(Properties.Settings.Default.nivelacessoConnectionString);

            /*destino onde o comando vai ser executado + connection string */
            SqlCommand cmd = new SqlCommand("SELECT * FROM tbUsuario WHERE usuario = @usuario and senha = @senha and nivelAcesso = @nivelAcesso", cn);
            cmd.Parameters.Add("@usuario", SqlDbType.VarChar).Value = usuarioComboBox;
            cmd.Parameters.Add("@senha", SqlDbType.VarChar).Value = senhaTextBox;
            cmd.Parameters.Add("@nivelAcesso", SqlDbType.VarChar).Value = nivelAcessoComboBox;
            cn.Open();

            SqlDataReader le = null;

            le = cmd.ExecuteReader();

            if (le.Read())
            {
                this.Hide();
                usuarioConectado = usuarioComboBox.Text;
                nivelAcesso = nivelAcessoComboBox.Text;
                frmMain tela = new frmMain();
                tela.Show();
            }
            else
            {
                MessageBox.Show("Usuario e/ou senha invalida");
            }
        }

    }
}