In general, it's considered good practice to have a constructor require the parameters needed in order to completely setup an object, so that it's impossible to create an object in an invalid state. However, there are often "extra" properties that could be set, but are not required. This could be handled through overloaded constructors, but leads to having lots of constructors that aren't necessarily useful in the majority of circumstances.
This leads to object initializers - An Object Initializer lets you set properties or fields on your object after it's been constructed, but before you can use it by anything else. However, in multi-threaded environments the atomicity of the object initializer may be beneficial, since it prevents the object from being in a not-fully initialized state see this answer for more details - it's either null or initialized like you intended.
Also, object initializers are simpler to read especially when you set multiple values , so they give you the same benefit as many overloads on the constructor, without the need to have many overloads complicating the API for that class.
A constructor is a defined method on a type which takes a specified number of parameters and is used to create and initialize an object. An object initializer is code that runs on an object after a constructor and can be used to succinctly set any number of fields on the object to specified values.
The setting of these fields occurs after the constructor is called. You would use a constructor without the help of an object initializer if the constructor sufficiently set the initial state of the object.
An object initializer however must be used in conjunction with a constructor. The syntax requires the explicit or implicit use VB. Net and C of a constructor to create the initial object. Now this facilitates behaviour like this. Knowing how object initializers work is important. If you have properties that MUST be set on your object for it to work properly, one way is to expose just a single constructor which requires those mandatory properties as parameters.
In that case, you cannot create your object without specifying those mandatory properties. Something like that cannot be enforced by object initializers.
Object initializers are really just a "syntax convenience" to shorten initial assignments. Nice, but not really very functionally relevant. A constructor is a method possibly accepting parameters and returning a new instance of a class. It may contain initialization logic. Below you can see an example of a constructor. You could achieve the same result as in the first example using an object initializer, assuming that you can access SomeClass, with the following code:. As you can see, an object initializer allows you to specify values for public fields and public settable properties at the same time construction is performed, and that's especially useful when the constructor doesn't supply any overload initializing certain fields.
Please mind, however that object initializers are just syntactic sugar and that after compilation won't really differ from a sequence of assignments. Follow C on Twitter! Also included is a virtual method that demonstrates why you should NOT call virtual methods from a constructor. This program writes to the console as each field and constructor is initialized so you can see the initialization order. Following is the console output from this sample program:. Field1 Derived. Field2 Derived.
Constructor Derived. Field2 Base. Field1 Base. Constructor Base. Field3 Derived. Virtual Derived. In this section, we will discuss the syntax for object initialization in more and more detail. Also, one practice example for beginners to make use of this while programming. To make use of object initialization in C , we have to follow some rules, which are defined as follows:.
We first have to create the object of the class or collection which we want, as we normally do in C. Immediately after the object creation, we are bound to assign the values to the class variable if you want to implement object initialization in C.
It is not mandatory to pass or assign values to all the variables to the object initialization; it depends upon the requirement. We have given force here because we are not using any constructor here to assign them the values. Object initialization also reduces the lines of code that is required to initialize the variable.
Also, we do not require to create the default and parameterized constructor for this. It also makes our code more readable and less in the number of lines. After this, we can assign any type of variable to it. Whether it is a string, number, or anything.
Now we will see one sample example for beginners to understand its internal working and implementation in a real scenario see below;. C Object Initializer is a new way to assign values at the time of object creation. It does not require constructor call to assign fields values. Object Initializer is enclosed in braces and values are separated by commas. Collection Initializer allows us to initialize a collection type that implements IEnumerable interface. The following example implements collection initializer.
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