why enum members need conversion

[Nikhil Patel]

Hi all,
I am a VB6 programmer and learning C#. I am currently reading a chapter
on types. I have question regarding enums. Why do we need to convert enum
members to the value that they represent?

Thanks in advance...

-Nikhil

[Nikhil Patel]

Thanks for the reply.
I think I didnt give more details on my question. Let me give an
example:

public enum Numbers
{
zero=0,
one=1,
two=2
}

now if I want to use Numbers.two in mathematical calculations, I need to
explicitly convert it to int as follows,

MessageBox.Show(((int)Numbers.two * 2).ToString()); //Displays 4

But if we use the Numbers enum in switch statement, we dont have to convert
it.

So my question is why do we have to convert the members in some cases.
VB.Net does not require the implicit conversion of the enum numbers even if
you use them in mathematical calculations.

Thanks...

-Nikhil

"Dmitri Shvetsov" <ds*******@cox.net> wrote in message
news:F%ESa.7423$Ne.7231@fed1read03...

It can be very helpful when you send these enums through interfaces for
example and these enum types are unknown in another objects.
Then if you use integer values for example in pairs to these enums you can
convert these values to integers and back, use in switch statements,
somewhere else. In 2 words - it's more flexible.

My example. I use these enums to define some errors in method parameters and can send these eror codes through the COM+ interface if I need. Then I can
use a switch based method to get an error string for any defined enum
values.

public enum Parameter {
E_Invalid = 1000,
E_IsNull = 1001,
E_IsEmpty = 1002,
E_NothingToDo = 1003
};

It depends what really do you need. Sometimes you can use an array of enums without integer analogs and this will also work.

Regards,
Dmitri.

"Nikhil Patel" <ni********@aol.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

Hi all,
I am a VB6 programmer and learning C#. I am currently reading a

chapter

on types. I have question regarding enums. Why do we need to convert enum members to the value that they represent?

Thanks in advance...

-Nikhil

[rubber21]

why? why?

SECURITY man. More RULES. RED TAPE. Or incapacitation if you look closer.
Don't enter the MATRIX! Don't lose your freedom! Stay with VB or better jump
to C++ if you want to know what FREESTYLE is.

open your eyes!

"Nikhil Patel" <ni********@aol.com> wrote in message
news:#u**************@tk2msftngp13.phx.gbl...

Hi all,
I am a VB6 programmer and learning C#. I am currently reading a chapter on types. I have question regarding enums. Why do we need to convert enum
members to the value that they represent?

Thanks in advance...

-Nikhil

[Jon Skeet]

[If this post comes through twice, but with a different last sentence,
take this one as the more correct one :) ]

Nikhil Patel <ni********@aol.com> wrote:

I am a VB6 programmer and learning C#. I am currently reading a chapter
on types. I have question regarding enums. Why do we need to convert enum
members to the value that they represent?

Type safety, basically. You have to prove to the compiler that you
really know that the variable in question is an enum and not an int,
but that in this case you want to treat it as an int, or vice versa.

Sometimes it gets in the way, other times it's useful.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet/
If replying to the group, please do not mail me too

[Jay B. Harlow [MVP - Outlook]]

Nikhil,
Learn to use Option Strict On in VB.NET! :-)

With option strict on VB.NET does require the explicit conversion of enums,
to perform math. The only 'math' operator defined for Enum types in VB.NET
is the Or operator to combine Enums that have the Flags attribute applied
for example. Of course you can compare two Enums and assign an Enum also.

You should normally use Option Strict On at the top of each of your VB.NET
files, to ensure compile time errors over run time errors. As Jon Skeet
stated, type safety!

Hope this helps
Jay

"Nikhil Patel" <ni********@aol.com> wrote in message
news:OU**************@TK2MSFTNGP10.phx.gbl...

error in last post.

Please read this line...
I said VB.Net does not require the implicit conversion of the enum
numbers even if you use them in mathematical calculations. Please read it
as, VB.Net does not require the explicit conversion of the enum numbers even if you use them in mathematical calculations.

Sorry about that.

"Nikhil Patel" <ni********@aol.com> wrote in message
news:u9**************@TK2MSFTNGP10.phx.gbl...

Thanks for the reply.
I think I didnt give more details on my question. Let me give an
example:

public enum Numbers
{
zero=0,
one=1,
two=2
}

now if I want to use Numbers.two in mathematical calculations, I need to
explicitly convert it to int as follows,

MessageBox.Show(((int)Numbers.two * 2).ToString()); //Displays 4

But if we use the Numbers enum in switch statement, we dont have to

convert

it.

So my question is why do we have to convert the members in some cases.
VB.Net does not require the implicit conversion of the enum numbers even

if

you use them in mathematical calculations.

Thanks...

-Nikhil

"Dmitri Shvetsov" <ds*******@cox.net> wrote in message
news:F%ESa.7423$Ne.7231@fed1read03...

It can be very helpful when you send these enums through interfaces for example and these enum types are unknown in another objects.
Then if you use integer values for example in pairs to these enums you can convert these values to integers and back, use in switch statements,
somewhere else. In 2 words - it's more flexible.

My example. I use these enums to define some errors in method

parameters

and

can send these eror codes through the COM+ interface if I need. Then I

can use a switch based method to get an error string for any defined enum
values.

public enum Parameter {
E_Invalid = 1000,
E_IsNull = 1001,
E_IsEmpty = 1002,
E_NothingToDo = 1003
};

It depends what really do you need. Sometimes you can use an array of

enums

without integer analogs and this will also work.

Regards,
Dmitri.

"Nikhil Patel" <ni********@aol.com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...
> Hi all,
> I am a VB6 programmer and learning C#. I am currently reading a
chapter
> on types. I have question regarding enums. Why do we need to convert

enum

> members to the value that they represent?
>
> Thanks in advance...
>
> -Nikhil
>
>