Re: Using enumerated types - C# Discussion Boards

6-Jun-07 3:56

OK, this is probably the C++ programmer in me still trying to break through the C# fog (so far it's been quite a pleasant learning curve though).

I woud like to "give names" to the values that my functions return. In my C++ days I would have used something like

#define OK                0<br />
#define ERR_PORT_NOT_OPEN -100<br />
#define ERR_NO_CARRIER    -101

etc.

A function can then return ERR_PORT_NOT_OPEN if the port is not open as opposed to a meaningless int value of -100.

So I thought I'd go with enumerated types in C# and while it works I do feel that it could be a little more elegant.

I wrote a class called Defines with an enumerated type resembling this:

public enum ERR<br />
{<br />
   OK = 0,<br />
   PORT_NOT_OPEN = -100,<br />
   NO_CARRIER = -101,<br />
}

so now a function can return Defines.ERR.PORT_NOT_OPEN as opposed to -100.

My gripe with this approach is that I'm constantly having to typecast this enumerated type to (int). In other words the function has to return (int)Defines.ERR.PORT_NOT_OPEN and if I want to compare the outcome of a function with a switch for instance I have to do something like:

switch (myFunc())<br />
{<br />
   case (int)Defines.ERR.PORT_NOT_OPEN:<br />
      ...<br />
      break;<br />
   case (int)Defines.ERR.NO_CARRIER:<br />
      ...<br />
      break;<br />
}

I don't want to change the return type of the functions from int to Defines.ERR because I still have to use native functions which return int values (corresponding to the #define values of course).

So what do you guys do to achieve what I'm trying to?

DavidNohejl6-Jun-07 4:05

DavidNohejl

6-Jun-07 4:05

Dewald wrote:
#define OK 0
#define ERR_PORT_NOT_OPEN -100
#define ERR_NO_CARRIER -101

static class ErrCodes
{
const int ERR_PORT_NOT_OPEN = -100;
const int ERR_NO_CARRIER -101;
...
}

"Throughout human history, we have been dependent on machines to survive. Fate, it seems, is not without a sense of irony. " - Morpheus
"Real men use mspaint for writing code and notepad for designing graphics." - Anna-Jayne Metcalfe

Dewald6-Jun-07 4:57

6-Jun-07 4:57

Thanks dnh, this looks great. Do you have any idea what the implications on memory usage is of this approach? The whole reason why, in C++ #defines were used is to save the memory that would have been allocated had the defines been constants or variables.

Guffa6-Jun-07 4:10

6-Jun-07 4:10

Dewald wrote:
I don't want to change the return type of the functions from int to Defines.ERR

This is your problem. As long as you want to use an int value, the coding will be somewhat painful.

If you want to avoid writing (int) here and there, you can create constants instead of using an enum. That would work pretty much as using #define in C++.

---
single minded; short sighted; long gone;

Dewald6-Jun-07 4:49

6-Jun-07 4:49

Thanks Guffa,

The reason I steered away from constants is because that would take up memory. I know memory conservation is probably not a big deal nowadays but I still tend to cringe when unneccesary memory is being taken up.

Dave Kreskowiak6-Jun-07 5:06

Dave Kreskowiak

6-Jun-07 5:06

Constants are only stored once, like a static. If you have a constant defined in a class and multiple objects created from that class, the runtime won't create multiple copies of the same constants. There will only be one copy of the constants in memory usable by every instance of the class.

In a world where a machine comes with 128M minumum, a few constants, or a few hundred constants, are not going to break the bank. An int32 constant is just 4 bytes. Even if you have 1,000 constants in a class and a thousand objects created from that class, you're still only using 4K for the constants.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Guffa6-Jun-07 9:05

6-Jun-07 9:05

Dave Kreskowiak wrote:
Constants are only stored once, like a static.

That is only true for reference type constants. Value type constants, like in this case, isn't stored anywhere. They are inlined in the code that uses it, producing the same code as if a literal value had been used.

Dave Kreskowiak wrote:
Even if you have 1,000 constants in a class and a thousand objects created from that class, you're still only using 4K for the constants.

Nope. Zero bytes.

---
single minded; short sighted; long gone;

Dewald6-Jun-07 20:50

6-Jun-07 20:50

Thanks guys,

That's very interesting and really god to know.

Guffa6-Jun-07 8:59

6-Jun-07 8:59

Dewald wrote:

The reason I steered away from constants is because that would take up memory.

No, they don't. Constants are inlined at compile time, so they don't take up more memory than literal values.

I prefer using an enum rather than constants in a case like this, as an enum says a lot more about what a method returns than an int does. When a method returns an enum value, you don't have to read a lot of documentation to find out what constants to use to compare the return value with.

If you want the int value you can easily cast the enum to int, and use that with any existing code that requires an int.

---
single minded; short sighted; long gone;

DavidNohejl6-Jun-07 21:23

DavidNohejl

6-Jun-07 21:23

Guffa wrote:
I prefer using an enum rather than constants in a case like this, as an enum says a lot more about what a method returns than an int does. When a method returns an enum value, you don't have to read a lot of documentation to find out what constants to use to compare the return value with.

If you want the int value you can easily cast the enum to int, and use that with any existing code that requires an int.

Agreed, he said it's native method (so he can't quite change the method return ~~value~~ type itself), but wrapper returning enum would do.

sending SMS

faldupuja6-Jun-07 3:42

faldupuja

6-Jun-07 3:42

I Don't know how to send SMS..
Is it requires any network protocols like http etc...or just adding code..
We don't want to use any type of hardware in our project..
Our site simply send sms to the user..

Re: sending SMS

Dave Herren6-Jun-07 6:36

Dave Herren

6-Jun-07 6:36

Here is a solution[^] using Api calls.

Or you could try this[^].

topcoderjax - Remember, Google is your friend.

Favourite Icon

vibhas19826-Jun-07 2:49

vibhas1982

6-Jun-07 2:49

how to add a favourite icon in url .

hello every one

Re: Favourite Icon

I Believe In GOD6-Jun-07 2:57

6-Jun-07 2:57

hi

just bring an icon

and rename it as
"favicon.ico" or "favico.ico" I don't remmber which one (sorry)

then put it in your site home dir (near your main index page)

P.S
I am not sure of this , but may be you can put an animated gif image like "favicon.gif" to do an animated icon ( I don't try this yet ) .......

have a good day ....

I know nothing , I know nothing

Re: Favourite Icon

I Believe In GOD6-Jun-07 3:01

6-Jun-07 3:01

I remembered it Roll eyes | :rolleyes:

it's "favicon.ico"

I know nothing , I know nothing

Re: Favourite Icon

Guffa6-Jun-07 3:59

6-Jun-07 3:59

This is quite comprehensive:

Wikipedia: favicon[^]

---
single minded; short sighted; long gone;

updating data

sneha016-Jun-07 2:19

sneha01

6-Jun-07 2:19

Hi,

I m working on ASP.net 2.0 with SQL 2005 as backend , how can i form a loop so that , for every row present in datatable, a stored procedure Should be executed and the output obtain should update each row from datatable in my original table in database .

foreach (DataRow rows in dt.Rows)

{

SqlCommand SpCmd = new SqlCommand("Select * from Table ");

SpCmd.Connection = MyConn;

SpCmd.CommandType = System.Data.CommandType.StoredProcedure;

SpCmd.CommandText = "usp_Calc_SP";

Com.ExecuteNonQuery();

}

I hve tried using for each cell row in datatable . But i think my loop is not working fine
Can anyone help me in this .
Thanks in advance D'Oh! | :doh:

Re: updating data

I Believe In GOD6-Jun-07 2:48

6-Jun-07 2:48

hi ...
I think your code is fine

but

sneha01 wrote:
Com.ExecuteNonQuery();

????

sorry for this , check what you wrote here Com

I know nothing , I know nothing

Re: updating data

ganti.r7-Jun-07 0:21

ganti.r

7-Jun-07 0:21

SqlCommand SpCmd = new SqlCommand("Select * from Table ");
this is may be wrong. When CommanType is StoredProcdure, you have to give the stor proc name:
though u are setting CommandText later check it out.

The culprit i feel is ExecuteNonQuery(). it should have been ExecuteQuery()

rAm
i Think, i Wait, i Fast -- Siddartha

Start process

gapfulgence6-Jun-07 2:18

gapfulgence

6-Jun-07 2:18

Hi,

I start a process using the Process.Start method with appropriate arguments.
I can see that the process is created.
However, when I try to get a handler on the process's main window , I get 0.
It seems to be because the process doesn't already have finished drawing itself.

How can I resolve this problem ?

Thanks !

p.f. Goudjo-Ako

Bringing our energy together !

I Believe In GOD6-Jun-07 2:40

6-Jun-07 2:40

Hi

Hope this will help you
even if I had a feel that my way is stupid ...

bool GetHandle;<br />
			GetHandle= false;<br />
			// Wait for 100 MillliSecond Before Get the Handle <br />
			int WaitingTime = 100;<br />
			Process pr = Process.Start("NotePad.exe");<br />
			while (GetHandle)<br />
			{<br />
				if (pr.StartTime.Ticks <= (DateTime.Now.Ticks - WaitingTime))<br />
				{<br />
					 GetHandle = true;<br />
				}<br />
			}<br />
			// Getting Handle ( as String just to know it's value )<br />
			MessageBox.Show (Handle.ToString());

Have a good day ....

I know nothing , I know nothing

gapfulgence6-Jun-07 2:49

gapfulgence

6-Jun-07 2:49

I'm going to try ur suggestion.
There's no stupid idea ! never !
Thanks a lor for helping.
I'll be back with comments.

p.f. Goudjo-Ako

Bringing our energy together !

gapfulgence6-Jun-07 3:04

gapfulgence

6-Jun-07 3:04

Since you start by intializing GetHandle to false, we'll never enter in the while loop. No ?

p.f. Goudjo-Ako

Bringing our energy together !

I Believe In GOD6-Jun-07 3:11