Skip to main content

Fields vs properties

De unde a pornit totul:
De la o discutie in care se spunea ca la inceput este mai bine sa folosim field-uri si nu proprietatiile, iar in cazul in care ajungem sa avem nevoie de ele, le putem înlocuii in orice moment cu propietati.

Aici apare o problema. Din punct de vedere a framework-ului field-urile si proprietatiile sunt total diferite (sunt binar incompatibile). Din aceasta cauza o sa fim nevoiti sa recompilam toate assembly-urile care folosesc obiectul nostru.
In cazul in care folosim reflection la accesarea field-urilor trebuie modificat, deoarece modul in care proprietatiilese acceseaza este diferit.
Singurul avantaj care apare la field-uri este performanta, care poate sa fie îmbunătățita foarte mult. Totodata field-urile pot sa fie folosite ca si parametri ref sau out.
Cand se folosesc propietati se poate controla modul in care valoarea se seteaza (validare) sau se obtine (get,set). In cazul in care modifiarea unei proprietati produce modificarea altor valori, acest lucru poate sa fie foarte usor de facut cu o proprietate.
Problema s-ar pune intre proprietăți automate si field-uri publice. Din punct de vedere a implementarii, este mult mai usor sa schimbam implementarea la o proprietate daca vrem sa facem ceva mai special, fara sa fim nevoiti sa recompilam toata solutia. De exemplu sa avem private setter.
Cea ce nu putem face cu proprietati, este sa le setam o valurea de default in mod automat. Acest lucru trebuie facut in constructor sau intr-o metoda de initializare.
  • Ca si concluzie o sa enumar avantajele pe care le avem daca folosim proprietati publice si nu field-uri publice:
  • lazy loading;
  • propietatiile pot sa arunce erori;
  • daca lucram cu data binding trebuie sa folosim propietati;
  • se poate adauga validare cand o valoare se seteaza;
  • fine-grained control (logging intr-un fisier de exemplu, validare);
  • pot sa fie virtual si se poate face overwritten;
  • pot sa apara in interfata;
Ce parere aveti? Exista un motiv pentru care am putea sa avem field-uri publice?

Comments

  1. Sunt putine cazuri in care e suficient un field public: de ex. clase care sigur vor fi folosite doar ca DTO-uri "dummy"..
    Altfel, overheadul unui property autoimplemented e neglijabil..

    ReplyDelete

Post a Comment

Popular posts from this blog

Windows Docker Containers can make WIN32 API calls, use COM and ASP.NET WebForms

After the last post , I received two interesting questions related to Docker and Windows. People were interested if we do Win32 API calls from a Docker container and if there is support for COM. WIN32 Support To test calls to WIN32 API, let’s try to populate SYSTEM_INFO class. [StructLayout(LayoutKind.Sequential)] public struct SYSTEM_INFO { public uint dwOemId; public uint dwPageSize; public uint lpMinimumApplicationAddress; public uint lpMaximumApplicationAddress; public uint dwActiveProcessorMask; public uint dwNumberOfProcessors; public uint dwProcessorType; public uint dwAllocationGranularity; public uint dwProcessorLevel; public uint dwProcessorRevision; } ... [DllImport("kernel32")] static extern void GetSystemInfo(ref SYSTEM_INFO pSI); ... SYSTEM_INFO pSI = new SYSTEM_INFO(

ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded

Today blog post will be started with the following error when running DB tests on the CI machine: threw exception: System.InvalidOperationException: The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application. See http://go.microsoft.com/fwlink/?LinkId=260882 for more information. at System.Data.Entity.Infrastructure.DependencyResolution.ProviderServicesFactory.GetInstance(String providerTypeName, String providerInvariantName) This error happened only on the Continuous Integration machine. On the devs machines, everything has fine. The classic problem – on my machine it’s working. The CI has the following configuration: TeamCity .NET 4.51 EF 6.0.2 VS2013 It see

Navigating Cloud Strategy after Azure Central US Region Outage

 Looking back, July 19, 2024, was challenging for customers using Microsoft Azure or Windows machines. Two major outages affected customers using CrowdStrike Falcon or Microsoft Azure computation resources in the Central US. These two outages affected many people and put many businesses on pause for a few hours or even days. The overlap of these two issues was a nightmare for travellers. In addition to blue screens in the airport terminals, they could not get additional information from the airport website, airline personnel, or the support line because they were affected by the outage in the Central US region or the CrowdStrike outage.   But what happened in reality? A faulty CrowdStrike update affected Windows computers globally, from airports and healthcare to small businesses, affecting over 8.5m computers. Even if the Falson Sensor software defect was identified and a fix deployed shortly after, the recovery took longer. In parallel with CrowdStrike, Microsoft provided a too