Using variables or fields dynamically and looping through sequentially named fields

[dantheinfoman]

Hi All,

Another stumper, I think. I'd like to loop through fields once a record is selected.

If I have fields named Cri1, Cri2, Cri3 etc up until Cri15, how can I loop between them dynamically?

For example, if I was analyzing just those three (Cri1, Cri2, and Cri3), Id rather do something like this

SCAN
	IF !DELETED() then    
		WITH thisform.nsavedSC
			.AddItem(cstrptnam)
                        for x = 1 to 3
                               IF !EMPTY(cri + x)
			          .AddListItem((cri + x), .NewIndex, x+1)
                               ENDIF
                        endfor
		ENDWITH                
	ENDIF
ENDSCAN

Rather than how I think I'll have to do it. . .

SCAN
	IF !DELETED() then    
		WITH thisform.nsavedSC
			.AddItem(cstrptnam)                        
                        if !EMPTY(cri1)
                           .AddListItem(cri1, .NewIndex, 2)
                        endif
                        if !EMPTY(cri2)
                           .AddListItem(cri2, .NewIndex, 3)
                        endif
                        if !EMPTY(cri3)
                           .AddListItem(cri3, .NewIndex, 4)
                        endif
                        *!* Ad infinitum. . .
		ENDWITH                
	ENDIF
ENDSCAN

Some languages allow this type of thing using EVALUATE or INDIRECT type functions. Thoughts?

Thanks great ones!
Dan

 

[Mike Lewis]

Yes, you can do this in VFP. You can use FIELD() or AFIELDS() to loop through the fields in a record; and you can use EVALUATE() to determined the contents of a field. So you will need something like this:

FOR lnI = 1 TO FCOUNT()
  ....
  luValue = EVALUATE(FIELDS(lnI))
  IF NOT EMPTY(luValue)
    .AddListItem(luValue, .NewIndex, lnI + 1)
  ...
  ENDIF
  ...
ENDFOR

The above is not meant to be fully working code. It's just to give you the general idea.

Mike


__________________________________
Mike Lewis (Edinburgh, Scotland)

Visual FoxPro articles, tips and downloads

 

[dmusicant]

EVALUATE() is a very handy function, it's fundamental to one of my favorite apps, which is extremely extensible by virtue of that function. The app uses metadata extensively.

 

[Olaf Doschke]

Instead of cri + x you need Evaluate("cri" + transform(x)).

Even if you come from javascript you can to "cri"+x there to get either "cri1","cri2" or "cri3", but you can't do cri+x in any programming language without cri on it's own existing as field or variable.
In any case you'd need to compose a full string of the name and either evaluate it or use macro substitution.

Bye, Olaf.

 

[dantheinfoman]

Thanks all, I can't wait to try this very soon! Brilliant!
Dan