Match content of two objects

Question

Use the method below to update a given table:

public int alteraBem(tb_bens itemBem)
{
    try
    {
        using (GestaoAtivoEntities db = new GestaoAtivoEntities())
        {
            var bem = db.tb_bens.Where(v => v.int_id_bem.Equals(itemBem.int_id_bem)).FirstOrDefault();

            bem.txt_tag_rfid = itemBem.txt_tag_rfid;
            bem.txt_codigo = itemBem.txt_codigo;
            bem.txt_descricao = itemBem.txt_descricao;
            bem.txt_modelo = itemBem.txt_modelo;
            bem.int_id_local = itemBem.int_id_local;
            bem.int_id_obra = itemBem.int_id_obra;
            bem.int_id_proprietario = itemBem.int_id_proprietario;

            ..... aqui vão os campos restantes......


            db.SaveChanges();

It would have to create a method to match the contents of objects dynamically, without having to be done manually one by one, with Reflection or something similar?

It may even seem more complicated to create a method than to move line by line, but I would like something like this IgualarConteúdo(origem, destino).

I am using classes generated by Entityframework through the database.

Answer 1

Hello,

There is a simple way to 'Inject' information from one object to another, there is an API called Valueinjecter, which does what you want. Simply put, Valueinjecter checks which fields have the same name between two objects and then transfers their values to an object.

Example of use:

Include the API namespace.

using Omu.Valueinjecter;

After that, inject the information through the Injectfrom extension.

objetoQueIraReceberOsDados.InjectFrom(objetoQueJaPossuiOsDados);

Anyway, there are examples of what else you can do with it in https://github.com/omuleanu/ValueInjecter

Answer 2

I don’t know how you’re dealing with competition in your project, but it doesn’t seem to me to be the safest way the way you’re doing.

If you’re working in a multi-user environment and multiple people take the same record (almost) at the same time, take time to update, if you’re not dealing with the competition, the last person you save will always beat the others.

But back to your question, your object (Row) should be Untracked. The best way to do this might not be to get the object again, by setting column by column and then saving, it would be better to get entities without tracking. This article is great to explain ways to do this.

  // quando obter a entidade, obtenha assim....
  var entidadeOrinal = Context.MinhaColecao
                              .AsNoTracking()
                              .FirstOrDefault(e => e.Id == 1);

  // (...)
  // aqui você deixa ser usado no seu MVC, WPF... 

  // na hora de salvar, faça isso (sem copiar)
  Context.MinhaColecao.Add(originalEntity);
  Context.SaveChanges();

The trick here is to make the context not track the modifications. It will think it is a new but modified entity. The cool thing is that it will end up discovering all the associated objects (daughter tables) and updating all of them in the bank as well.

I didn’t go into the details of the competition here, but I think it would be important for you to investigate. If the system is multi-user, either it will constantly fail or there will be a continuous loss of information.

EDITION

Doing a survey, I found this answer: https://stackoverflow.com/questions/2185155/cloning-data-on-entity-framework

There are two ways to make the copy.

1. Serialization

     private static T DataContractSerialization<T>(T entidade) {
         DataContractSerializer dcSer = new DataContractSerializer(entidade.GetType());
         MemoryStream memoryStream = new MemoryStream();
   
         dcSer.WriteObject(memoryStream, entidade);
         memoryStream.Position = 0;
   
         T entidadeCopiada = (T)dcSer.ReadObject(memoryStream);
         return entidadeCopiada;
     }
   

2. Reflection - In this case, it is necessary to accompany Article: http://blogs.msmvps.com/matthieu/2008/05/31/entity-cloner/