Explicit Type Conversion in C #

Question

I understand type conversion. For example:

class Person { } class Student : Person { }

Implicit conversion:

 Person p = new Student();

Explicit conversion:

 Person p = new Person(); p = (Student)p;

In this case, the compiler allows the conversion, but throws an exception when executed.

So when is explicit type conversion allowed in C # and how can this be demonstrated with this example?

along the way there is a problem with materiel. A student is always a person, and a person is not always a student.
The question is: if not here, where can an explicit conversion be applied?
Well, the opposite is true, either if you are sure that p is a student (well, either check (p instanceof Student), or whatever it is in the details) Person p = new Student ();

Answer 1 · 2013-01-16T14:04:16

Explicit type conversion in C # is permissible in two cases :

A. Explicit conversion of arithmetic types. Example:

 double pi = 3.1415926; int entier = (int)pi;

B. Class conversion within the inheritance hierarchy:

 Student s = (Student)person; // тут возможно исключение

Notice that conversion between types that are not related in the inheritance hierarchy is not possible in C #:

 string s = (string)person; // ошибка компиляции

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