Skip to main content

Caz in care IValidatableObject.Validate nu este apelat

Daca in aplicatia voastra MVC in loc de Enterprise library pentru validare o sa fiti surprinsi ca exista cazuri cand metoda pentru validare nu este apelata asa cum v-ati astepta.
Folosind atributele HasSelfValidate si SelfValidate, putem sa validam un obiect. Atributul HasSelfValidate ne spune daca obiectul curent are un mecanism propiu de validare. Metoda care face validarea in interiorul obiectului nostru trebuie sa aibe atributul SelfValidation si urmatorul antet:
void numeMetoda( ValidationResults validationResults )
In cazul in care obiectul nu este valid putem sa adaugam pe validationResults mesajul dorit impreuna cu alte informatii precum: nume propietate si referinta la obiectul care nu este valid.
[HasSelfValidate]
public class Person
{
public int Age { get; set; }

public int Name { get; set; }

[SelfValidation]
public void Validate(ValidationResults validationResults)
{
if( Age < 0 )
{
validationResults.AddResult(new ValidationResult("Varsta este negativa", this, "Age", null,null);
}
if( string.IsNullOrEmpty( Name ) )
{
validationResults.AddResult(new ValidationResult("Numele nu este valid", this, "Name", null,null);
}
}
}
In cazul unei aplicatii MVC clasa noastra o sa aibe forma urmatoare:
public class Person : IValidatableObject
{
[Required]
public int Age { get; set; }

[Required]
public int Name { get; set; }

public IEnumerable[ValidationResult] Validate(ValidationContext validationContext)
{
if( Age < 0 )
{
yield return new ValidationResult("Varsta este negativa", new [] { "Age" });
}
if( string.IsNullOrEmpty( Name ) )
{
yield return new ValidationResult("Numele nu este valid", new[] { "Name"});
}
}
}
Mecanismul este exact la fel ca si cel cu atribute, doar ca implementam o interfata. Am putea spune ca cele doua implementări au același comportament pentru orice caz. Dar din pacate nu este adevarat. Pentru a doua implementare o sa apara cazuri cand metoda noastra de validare nu se apelează.
Daca Age sau Name nu este completat o observam ca metoda Validate nu este apelata. Totul apare din cauza atributului Required, care verifica daca s-a introdus o valoarea pentru propietatea marcata, iar daca valoarea nu a fost introdusa nu o sa apeleze metoda Validate. Acest comportament apare din cauza ca prima data se face validarea propietatiilor in functie de atirbutele cu care sunt decorate, iar doar apoi daca validarea a fost cu succes se apeleaza metoda noastra
Acest caz nu ar trebuii sa ne deranjeze in general. Dar trebe sa il avem in vedere pentru anumite cazuri. De exemplu faca avem o pagina unde un user se inregistreaza si acesta nu introduce numele, dar introduce parola, poate am dorii sa apara un mesaj in care sa ii se spuna ca parola nu este destul de sigura sau ceva asemanator.

Comments

Popular posts from this blog

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 4.51EF 6.0.2VS2013
It seems that there …

How to check in AngularJS if a service was register or not

There are cases when you need to check in a service or a controller was register in AngularJS.
For example a valid use case is when you have the same implementation running on multiple application. In this case, you may want to intercept the HTTP provider and add a custom step there. This step don’t needs to run on all the application, only in the one where the service exist and register.
A solution for this case would be to have a flag in the configuration that specify this. In the core you would have an IF that would check the value of this flag.
Another solution is to check if a specific service was register in AngularJS or not. If the service was register that you would execute your own logic.
To check if a service was register or not in AngularJS container you need to call the ‘has’ method of ‘inhector’. It will return TRUE if the service was register.
if ($injector.has('httpInterceptorService')) { $httpProvider.interceptors.push('httpInterceptorService&#…

Fundamental Books of a Software Engineer (version 2018)

More then six years ago I wrote a blog post about fundamental books that any software engineer (developer) should read. Now it is an excellent time to update this list with new entries.

There are 5 different categories of books, that represent the recommended path. For example, you start with Coding books, after that, you read books about Programming, Design and so on.
There are some books about C++ that I recommend not because you shall know C++, only because the concepts that you can learn from it.

Coding

Writing solid codeCode completeProgramming Pearls, more programming pearls(recommended)[NEW] Introduction to Algorithms

Programming

Refactoring (M. Fowler)Pragmatic ProgrammerClean code[NEW] Software Engineering: A Practitioner's Approach[NEW] The Mythical Man-Month[NEW] The Art of Computer Programming

Design

Applying UML and Patterns (GRASP patterns)C++ coding standards (Sutter, Alexandrescu)The C++ programming language (Stroustrup, Part IV)Object-oriented programming (Peter Coad)P…