Re: mixed struct with constant and variable data

[Alberto Poblacion]

"markus wolfgart" <ma*************@dlr.dewrote in message
news:6n************@mid.dfncis.de...

public struct PFD_Order_T
{
[...]
public const string key_order_id = "order_id";
[...]
PFD_Order_T PfdOrder;
[...]
pfdorder.order_id =
extract_from_order_line(fileLine,pfdorder.key_orde r_id); <=== My problem
[...]
I could not select my constant part of my struct like I demonstrate above.
Means pfdorder.key_order_id is for me not visible in vs2005 where
as pfdorder.order_id could be selected.

Any hints whats wrong with my definition of the struct PFD_Order_T.

Nothing wrong with the struct, but with the code that accesses the
constant. The "const" is automatically considered "static", which means that
you have to access it like a static member, using the name of the struct
instead of the instance:

PFD_Order_T.key_order_id instead of pfdorder.key_order_id.

[markus wolfgart]

Alberto Poblacion schrieb:

"markus wolfgart" <ma*************@dlr.dewrote in message
news:6n************@mid.dfncis.de...

>public struct PFD_Order_T
{
[...]
public const string key_order_id = "order_id";
[...]
PFD_Order_T PfdOrder;
[...]
pfdorder.order_id =
extract_from_order_line(fileLine,pfdorder.key_ord er_id); <=== My problem
[...]
I could not select my constant part of my struct like I demonstrate
above. Means pfdorder.key_order_id is for me not visible in vs2005 where
as pfdorder.order_id could be selected.

Any hints whats wrong with my definition of the struct PFD_Order_T.

Nothing wrong with the struct, but with the code that accesses the
constant. The "const" is automatically considered "static", which means
that you have to access it like a static member, using the name of the
struct instead of the instance:

PFD_Order_T.key_order_id instead of pfdorder.key_order_id.

Thanks Alberto for your reply.

My understanding was that every object of type PFD_Order_T created by
the new operator is a clone of my struct 'PFD_Order_T' placed in memory.
Is in this case every constant part of my struct only one time allocated
in the memory, whereas the dynamic part will be created every time I use
the new operator?

My intension was to bundle the keys for data extraction with the
structure where my dynamic data will be stored.

But when I have to use an other name to access my keys then to access my
data, which sense makes it to encapsulate my keys and my data in one
structure.

Should I separate the constant keys (patterns) from my extracted data?
Bye

Markus

[Alberto Poblacion]

"markus wolfgart" <ma*************@dlr.dewrote in message
news:6n************@mid.dfncis.de...

My understanding was that every object of type PFD_Order_T created by
the new operator is a clone of my struct 'PFD_Order_T' placed in memory.
Is in this case every constant part of my struct only one time allocated
in the memory, whereas the dynamic part will be created every time I use
the new operator?

Yes, the dynamic parts are allocated each time, but since the "const" is
invariable, it is treated as "static", that is, it is allocated a single
time.

My intension was to bundle the keys for data extraction with the
structure where my dynamic data will be stored.

But when I have to use an other name to access my keys then to access my
data, which sense makes it to encapsulate my keys and my data in one
structure.

It would make sense if you wanted to encapsulate the whole functionality
together: the data, the keys, and the method that operate on the data and
keys. However, this is more typically done with a class instead of a struct.

Should I separate the constant keys (patterns) from my extracted data?

Possibly, depending on how your program is intended to operate. It may
make sense to create a "decoder" class which has the const keys and the
methods that access the data by means of those keys, and then create a very
simple separate struct to contain only the data values upon which the class
methods operate. These stucts would not contain any methods or constants.
The class could be entirely static, if it doesn't need to maintain any
state.