Re: Types of constructors

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I private constructor is a constructor that is only available to the same class. They can be useful in factory scenarios, where a class creates other instances of its own class and you don't want other classes to be able to instantiate the class in the same way.

For example:

public class Foo {
  string name;

  // this is the only constructor available to other classes
  // other classes cannot set the name field directly
  public Foo(){
    this.name = "DefaultName";
  }

  // this constructor is not available to other classes
  // it allows the name field to be set
  private Foo(string name){
    this.name = name;
  }

  // other classes can call this factory method
  public Foo CreateFoo(string fooName){
    // calls the private constructor
    // and returns a new Foo with the name "fooName"
    return new Foo(fooName);
  }

  public string Name { get { return this.name; } }
}


You can also have static constructors, which can be used to initialize static fields of the class.
static Foo() { // initialize static fields }


Joshua Flanagan
http://flimflan.com/blog

Sathyaish wrote: 
What is a private constructor, and why would a class have one? What are
the other kinds of constructors besides:

(1) public constructors; and
(2) parameterized constructors

And I understand that they are not mutually exclusive of one another.
The above classification assimilates my knowledge of having used
constructors in both the above manners.

.

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