Defining and using enums

[JScannell]

According to Microsoft:

The enum keyword is used to declare an enumeration, a distinct type that consists of a set of named constants called the enumerator list.

Usually it is best to define an enum directly within a namespace so that all classes in the namespace can access it with equal convenience. However, an enum can also be nested within a class or struct.


However, if I try placing several enums inside a namespace but before any classes are defined, I can't use the enum.

Here's an example of what doesn't work:
namespace CommonFunctions
{
public enum fldsJobSpecs
{
fldJOBSPECS_JobNumber,
fldJOBSPECS_Nuclear,
fldJOBSPECS_PlusMinus
};

public class CommFuncs
{
.
.
.


This seems to be the only thing that works:
namespace CommonFunctions
{
public class CommFuncs
{
public enum fldsJobSpecs
{
fldJOBSPECS_JobNumber,
fldJOBSPECS_Nuclear,
fldJOBSPECS_PlusMinus
};
.
.
.

Why?

Also, when I reference the enum, I have to fully qualify the value like:

dr[(int)CommFuncs.fldsJobSpecs.fldJOBSPECS_LastUpdated].ToString()

even though I have this declarative:

using CommonFunctions;


and this code:
public CommFuncs cf = new CommFuncs();

I can't reference the enum utilizing the 'cf'

Thanks in advance,



Jerry Scannell

 

[Qik3Coder]

You have to have the class to contain the enum.
if you make the class STATIC, you can reference it without a new.
You will need the class name regardless, so that there's no confusion which enum you wanted.

HTH,
Lodlaiden

If [blue]you have problems[/blue], I want [green]source code[/green] AND [green]error messages[/green], none of this [red]"there was an error crap"[/red]

 

[JScannell]

Thanks. Can you give me an example of what a static class would look like as it pertains to having enums in it?


Jerry Scannell

 

[jmeckley]

he's talking about the static keyword.

class Foo
{
   public enum Fu {a,b,c};
}

static class Bar
{
   public enum Bu {e,f,g};
}

Fu fus = new Foo().Fu;
Bu bus = Bar.Bu;

Jason Meckley
Programmer

faq855-7190
faq732-7259

 

[JScannell]

I did what you suggested. It works, however, there is compiler warning error that reads:
Warning 3 Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated. C:\Documents and Settings\cransca\My Documents\Visual Studio 2005\Projects\PSDS\PSDS\frmJobCopy.vb 38 31 PSDS

Here's what I did:
1. I created a separate .cs file that has
using System;
using System.Collections.Generic;
using System.Text;

public static class dbColumnEnums
{
public enum fldsJobSpecs : int
{
fldJOBSPECS_JobNumber,
fldJOBSPECS_Nuclear,
fldJOBSPECS_PlusMinus,
.
.
.
.

Referencing this class (which is part of a .dll) is like this:
Public dbJS As New dbColumnEnums.fldsJobSpecs()

Then using them is like this:
dim s as string = dr(dbJS.fldJOBSPECS_JobNumber).ToString()

That's where I get the warning error. Why?

Thanks in advance,



Jerry Scannell

 

[jmeckley]

I would avoid static references as much as possible. they make testing and debugging more difficult. there are few times you would need to nest an enum/class/struct within another class.

I would keep the classes as instance types and move the enum outside the scope of the class.

namespace ...
{
   public enum Fu
   {
       Bar,
       Baz
   }

   public class Foo
   {
      public void DosomethingWith(Fu f)
      {
          ....
      }
   }
}

var foo = new Foo();
foo.DosomethingWith(Fu.Bar);

Jason Meckley
Programmer

faq855-7190
faq732-7259