LevelOS-Core/DAL/DALBancos.cs

using Microsoft.Data.SqlClient;
using MLL;
using System;
using System.Collections.Generic;
using System.Data;

namespace DALL
{
    public class DALBancos
    {
        private readonly string _conexao;

        public DALBancos(string conexao)
        {
            _conexao = conexao;
        }

        #region INSERT
        public bool Inserir(string numero, string nome)
        {
            try
            {
                using (SqlConnection conn = new SqlConnection(_conexao))
                {
                    string sql = @"INSERT INTO Bancos (NUMERO, NOME)
                                   VALUES (@NUMERO, @NOME)";

                    using (SqlCommand cmd = new SqlCommand(sql, conn))
                    {
                        cmd.Parameters.AddWithValue("@NUMERO", (object?)numero ?? DBNull.Value);
                        cmd.Parameters.AddWithValue("@NOME", (object?)nome ?? DBNull.Value);

                        conn.Open();
                        return cmd.ExecuteNonQuery() > 0;
                    }
                }
            }
            catch
            {
                return false;
            }
        }//Inserir
        #endregion

        #region UPDATE
        public bool Alterar(int id, string numero, string nome)
        {
            try
            {
                using (SqlConnection conn = new SqlConnection(_conexao))
                {
                    string sql = @"UPDATE Bancos 
                                   SET NUMERO = @NUMERO,
                                       NOME = @NOME
                                   WHERE ID_BANCOS = @ID";

                    using (SqlCommand cmd = new SqlCommand(sql, conn))
                    {
                        cmd.Parameters.AddWithValue("@ID", id);
                        cmd.Parameters.AddWithValue("@NUMERO", (object?)numero ?? DBNull.Value);
                        cmd.Parameters.AddWithValue("@NOME", (object?)nome ?? DBNull.Value);

                        conn.Open();
                        return cmd.ExecuteNonQuery() > 0;
                    }
                }
            }
            catch
            {
                return false;
            }
        }//alterar
        #endregion

        #region DELETE
        public bool Excluir(int id)
        {
            try
            {
                using (SqlConnection conn = new SqlConnection(_conexao))
                {
                    string sql = "DELETE FROM Bancos WHERE ID_BANCOS = @ID";

                    using (SqlCommand cmd = new SqlCommand(sql, conn))
                    {
                        cmd.Parameters.AddWithValue("@ID", id);

                        conn.Open();
                        return cmd.ExecuteNonQuery() > 0;
                    }
                }
            }
            catch
            {
                return false;
            }
        }//Excluir
        #endregion

        #region SELECT TODOS (DataTable)
        public DataTable LocalizarTodos()
        {
            DataTable tabela = new DataTable();

            using (SqlConnection conn = new SqlConnection(_conexao))
            {
                string sql = "SELECT * FROM Bancos ORDER BY NOME";

                using (SqlDataAdapter da = new SqlDataAdapter(sql, conn))
                {
                    da.Fill(tabela);
                }
            }

            return tabela;
        }//LocalizarTodos
        #endregion

        #region SELECT LISTA (opcional - forte tipagem)
        public List<(int id, string numero, string nome)> ListarLista()
        {
            var lista = new List<(int, string, string)>();

            using (SqlConnection conn = new SqlConnection(_conexao))
            {
                string sql = "SELECT ID_BANCOS, NUMERO, NOME FROM Bancos ORDER BY NOME";

                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    conn.Open();

                    using (SqlDataReader dr = cmd.ExecuteReader())
                    {
                        while (dr.Read())
                        {
                            lista.Add((
                                Convert.ToInt32(dr["ID_BANCOS"]),
                                dr["NUMERO"]?.ToString(),
                                dr["NOME"]?.ToString()
                            ));
                        }
                    }
                }
            }

            return lista;
        }//ListarLista
        #endregion

        #region SELECT POR NUMERO
        public string ObterNomePorNumero(string numero)
        {
            try
            {
                using (SqlConnection conn = new SqlConnection(_conexao))
                {
                    string sql = "SELECT NOME FROM Bancos WHERE NUMERO = @NUMERO";

                    using (SqlCommand cmd = new SqlCommand(sql, conn))
                    {
                        cmd.Parameters.AddWithValue("@NUMERO", numero);

                        conn.Open();

                        object result = cmd.ExecuteScalar();

                        return result != null ? result.ToString() : null;
                    }
                }
            }
            catch
            {
                return null;
            }
        }//ObterNomePorNumero
        #endregion
        public ModeloBancos CarregarModeloBanco(int cod)
        {
            ModeloBancos banco = null;

            using (SqlConnection conn = new SqlConnection(_conexao))
            {
                string sql = "SELECT * FROM Bancos WHERE ID_BANCOS = @ID";

                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    cmd.Parameters.AddWithValue("@ID", cod);

                    conn.Open();

                    using (SqlDataReader dr = cmd.ExecuteReader())
                    {
                        if (dr.Read())
                        {
                            banco = new ModeloBancos
                            {
                                ID_BANCOS = Convert.ToInt32(dr["ID_BANCOS"]),
                                NUMERO = dr["NUMERO"]?.ToString(),
                                NOME = dr["NOME"]?.ToString()
                            };
                        }
                    }
                }
            }

            return banco;
        }//CarregarModeloBanco

    }
}