private void btnLogin_Click(object sender, EventArgs e) { bool found = false; Operador usuario = new Operador(); if ((txbId.TextLength > 0) && (txbSenha.TextLength > 0)) { using (SqlConnection sqlConn = new SqlConnection(@"Data Source=(localdb)\Av2DotNet;Initial Catalog=estoque;Integrated Security=True")) { using (SqlCommand sqlCommand = new SqlCommand()) { sqlCommand.CommandText = "SELECT id, senha, nome, tipo FROM operador"; sqlCommand.Connection = sqlConn; sqlConn.Open(); SqlDataReader dataReader; dataReader = sqlCommand.ExecuteReader(); //para caso que retorna registros while ((found == false) && (dataReader.Read())) //encontrou registro { usuario.Id = Int32.Parse(dataReader[0].ToString()); usuario.Senha = dataReader[1].ToString(); usuario.Nome = dataReader[2].ToString(); usuario.Tipo = int.Parse(dataReader[3].ToString()); if (usuario.Id == Int32.Parse(txbId.Text)) { if (usuario.Senha == txbSenha.Text) { found = true; } } } sqlConn.Close(); } } if (found == true) { this.Hide(); FormPrincipal formPrincipal = new FormPrincipal(usuario, this); formPrincipal.Show(); } else MessageBox.Show("Login inválido!", "Erro ao efetuar login", MessageBoxButtons.OK, MessageBoxIcon.Error); } else { string errorMessage = string.Empty; if (txbId.TextLength == 0) errorMessage += "Id vazio!" + Environment.NewLine; if (txbSenha.TextLength == 0) errorMessage += "Senha vazia!" + Environment.NewLine; MessageBox.Show(errorMessage, "Erro ao efetuar login", MessageBoxButtons.OK, MessageBoxIcon.Error); } }