base() and this() constructors best practices

Question

Under what conditions am I supposed to make the :base() and :this() constructor calls following my constructor\'s parentheses (or even in other pl

Answer 1

You use :base() when you want the constructor of the base class to be automatically called as first instruction of your constructor. :this() it's similar, but it call another constructor on the same class.

In base:() and this(): you can pass as parameters constant values , or expression based on parameters of you constructor.

It's mandatory to call the base constructor when the base class has no default constructor (one that takes no parameters). I don't know of a case in which :this() is mandatory.

public class ABaseClass
{
    public ABaseClass(string s) {}
}

public class Foo : AChildClass
{
    public AChildClass(string s) : base(s) {} //base mandatory
    public AChildClass() : base("default value") {}  //base mandatory
    public AChildClass(string s,int i) : base(s+i) {}  //base mandatory
}

public class AnotherBaseClass
{
    public ABaseClass(string s) {}
    public ABaseClass():this("default value") {} //call constructor above
}

public class Foo : AnotherChildClass
{
    public AnotherChildClass(string s) : base(s) {} //base optional

}