C#

George_George wrote:

Could we unbox to a type's base type?

public class TypeX {}

public class TypeY : TypeX {}

TypeY y = new TypeY();
object o = y;
TypeX x = (TypeX)o;

public class Animal {}
public class Dog : Animal {}
public class Horse : Animal {}

Animal hero = new Horse();
object o = hero;
Animal horsie = (Animal)o;

George_George wrote:

"A value type can not inherit another value type" -- so Object is just the base for all reference type, not value type?

George_George wrote:

I do not agree with it, since all value types inherit from System.ValueType, and System.ValueType inherits from Object. Any comments?

// this is allowed<br />
enum MyEnum : int { asdf }<br />
<br />
// but not this<br />
enum MyEnum : System.Int32 { asdf }

George_George wrote:

Good to learn from you. I have never used type information after Enum to restrict the type of Enum -- and just use the default one -- I think it is int type?

George_George wrote:

what types could be used with Enum definition to define the type of the Enum?

George_George wrote:

I read the link and find there is a comment like this -- "Notice that if you remove the initializer from Sat=1, the result will be ...", my confusion is in the related sample, are there any Enum element named Sat?

int i = 100;
object b = (object)i;
long l = (long)b;

John Simmons / outlaw programmer wrote:

What you should have done was:

int i = 100;
object b = (object)i;
long l = (long)b;

int i = 100;
object b = i;
long l = (int)b;

John Simmons / outlaw programmer wrote:

Nope - it'll still fail.