Cast from int to constants possible?

[Daniel Bass]

I've got some class which contains loads of static const int values, is
there a way that, given an int, i can quickly cast the int back to a string
representation of the const?

for eg.

MyClass contains
const int ERROR_NONE = 1
const int ERROR_NO_DRIVE = 2
const int ERROR_INSUFFICI ENT_DISK_SPACE = 3
....
etc.

and given an int value of say 3, I'm able to display an error message saying
something like:

string errMsg = "Error! Code: " + ((MyClass)(nErr orCode)).ToStri ng();

Thanks!

[Jon Skeet [C# MVP]]

Re: Cast from int to constants possible?

<"Daniel Bass" <I'm really @ sick of spam>> wrote:[color=blue]
> I've got some class which contains loads of static const int values, is
> there a way that, given an int, i can quickly cast the int back to a string
> representation of the const?
>
> for eg.
>
> MyClass contains
> const int ERROR_NONE = 1
> const int ERROR_NO_DRIVE = 2
> const int ERROR_INSUFFICI ENT_DISK_SPACE = 3
> ....
> etc.
>
> and given an int value of say 3, I'm able to display an error message saying
> something like:
>
> string errMsg = "Error! Code: " + ((MyClass)(nErr orCode)).ToStri ng();[/color]

No. Instead of having consts, use an enumeration instead - then you get
type safety *and* you can go back to the name easily.

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[Daniel Bass]

Re: Cast from int to constants possible?

[color=blue]
> No. Instead of having consts, use an enumeration instead - then you get
> type safety *and* you can go back to the name easily.[/color]

I would, but the class of constants isn't mine, stupid for me to put
"MyClass"!! !

Should've put "ClassOfConstan tsGivenToMeThat ICan'tAlter" ! ;o)

Agree that enums are far superior.

Thanks.
Dan.

[Jon Skeet [C# MVP]]

Re: Cast from int to constants possible?

<"Daniel Bass" <I'm really @ sick of spam>> wrote:[color=blue][color=green]
> > No. Instead of having consts, use an enumeration instead - then you get
> > type safety *and* you can go back to the name easily.[/color]
>
> I would, but the class of constants isn't mine, stupid for me to put
> "MyClass"!! !
>
> Should've put "ClassOfConstan tsGivenToMeThat ICan'tAlter" ! ;o)
>
> Agree that enums are far superior.[/color]

I'd define an enumeration with the same values, and use that everywhere
you can. Where you can't, just cast from the int to the enum type. Does
that help? The only problem is what happens if the set of errors
changes - do you get new versions of this class on a regular basis?

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[Daniel Bass]

Re: Cast from int to constants possible?


It's IBM's MQSeries .Net interface.
(
http://www-1.ibm.com/support/docview...&cc=us&lang=en )

I prefer MSMQ for messages, IBM's version is too clever and mucks up every
time.

So when you a catch an expection, you ask for the message and it gives you
back something like " Code: 2, Reason: 2018", which might be something like
invalid queue handle, but there's no way of easily checking that.

If i press F12 to check the definition, it brings up the object explorer for
the class which doesn't say what the values of each const int is.

Thanks for your time.
Dan.

"Jon Skeet [C# MVP]" <skeet@pobox.co m> wrote in message
news:MPG.1a240c 8450eb82c5989ac c@msnews.micros oft.com...
<"Daniel Bass" <I'm really @ sick of spam>> wrote:[color=blue][color=green]
> > No. Instead of having consts, use an enumeration instead - then you get
> > type safety *and* you can go back to the name easily.[/color]
>
> I would, but the class of constants isn't mine, stupid for me to put
> "MyClass"!! !
>
> Should've put "ClassOfConstan tsGivenToMeThat ICan'tAlter" ! ;o)
>
> Agree that enums are far superior.[/color]

I'd define an enumeration with the same values, and use that everywhere
you can. Where you can't, just cast from the int to the enum type. Does
that help? The only problem is what happens if the set of errors
changes - do you get new versions of this class on a regular basis?

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[100]

Re: Cast from int to constants possible?

[color=blue]
> Agree that enums are far superior.[/color]
Not always, though.
Imagin that we have class hierarchy for Items let say

public enum ItemType{Pencil , Notebook}
public class abstract Item
{
public abstract ItemType Type
{
get;
}
}
class Pencil: Item
{
public override ItemType Type
{
get{return ItemType.Pencil ;}
}

}
class Notebook: Item
{
public override ItemType Type
{
get{return ItemType.Notebo ok;}
}
}

If you use enums for the type as I do. You cannot extend the hierarchy with
new Items because you cannot inherit the enumeration.

But if we had
public class abstract Item
{
public abstract int Type
{
get;
}
}

and

public class ItemType
{
public const int Pencil = 1;
public const int NoteBook = 2;
}

So, we could do
class MyItemTypes: ItemType
{
public const int Staple = 3;
}

What you can do in your case is

class MyNewClass: MyClass
{
private int mErrCode;
public static explicit operator MyNewClass(int errCode)
{
MyNewClass res = new MyNewClass();
res.mErrCode = errCode;
return res;
}
public override string ToString()
{
string res = "";
switch(mErrCode )
{
case 1:
res = "ERROR_NONE ";
break;
case 2:
res = "ERROR_NO_DRIVE ";
break;
case 3:
res = "ERROR_INSUFFIC IENT_DISK_SPACE ";
break;
default:
res = "UNKNOWN ERROR";
break;
}
return res;
}
}

Now you can write

string errMsg = "Error! Code: " + ((MyNewClass)nE rrorCode).ToStr ing();

or

string errMsg = "Error! Code: " + ((MyNewClass)2) .ToString();


Ofcourse with enums it would be easier, but since you don't have control
over it this will work for you.

HTH
B\rgds
100