Skip to main content

Default value and TryParse

Ce vi se pare ciudat in urmatorul cod?
int value;
if(!int.TryParse(text.ToString(), out value))
{
value = 0;
}
In mod default, toate tipurile de numere de tip value type au valoarea default 0. Din aceasta cauza nu mai este nevoie sa setam value 0. Ajunge sa avem doar urmatorul cod:
int value;
int.TryParse(text.ToString(), out value);
In cazul in care vrem sa obtinem valoarea default pentru orice tip de data putem sa ne folosim de "default". Acest keyword returneaza null pentru toate tipurile referinta si 0 (zero) pentru value type. In cazul structuriilor acesta o sa returneze structura noastra, iar fiecare element din structura o sa fie inializat cu default value pentru acesta.
var value1 = default(int);        // 0
var value2 = default(double); // 0
public struct Point
{
public int x, y;
public Point(int x, int y)
{
this.x = x;
this.y = y;
}
}
var value3 = default(Point); // X si Y o sa fie 0
var value 4 = default(MyCustomClass) // null

In cazul in care vrem ca codul nostru sa fie mai usor de inteles putem ca in momentul in care il declaram pe value sa il setam cu default(int) sau cu 0. Eu prefer a doua varianta deoarece este mult mai usor de citit.

Comments

  1. Problema cu bucata nr.2 de cod (`int value;
    int.TryParse(text.ToString(), out value);`) este ca daca iti vine zero nu stii daca zero era efectiv in string-ul respectiv sau a esuat parse-area...

    ReplyDelete
    Replies
    1. Drept. In primul exemplu, se seta valoarea default la 0 daca parsa a esuat (nu mai era nevoie sa executam sau sa logam ceva daca aceasta a eusat). In al doilea exemplu se obtine acelasi comportament, valoarea default fiind setata pe 0.

      Delete

Post a Comment

Popular posts from this blog

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&#…

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 …

Run native .NET application in Docker (.NET Framework 4.6.2)

Scope
The main scope of this post is to see how we can run a legacy application written in .NET Framework in Docker.

Context
First of all, let’s define what is a legacy application in our context. By a legacy application we understand an application that runs .NET Framework 3.5 or higher in a production environment where we don’t have any more the people or documentation that would help us to understand what is happening behind the scene.
In this scenarios, you might want to migrate the current solution from a standard environment to Docker. There are many advantages for such a migration, like:

Continuous DeploymentTestingIsolationSecurity at container levelVersioning ControlEnvironment Standardization
Until now, we didn’t had the possibility to run a .NET application in Docker. With .NET Core, there was support for .NET Core in Docker, but migration from a full .NET framework to .NET Core can be costly and even impossible. Not only because of lack of features, but also because once you…