passing a value through a for..next loop

[Silvio.Falconi]

If I have a loop For ..Next
and on this cicle I have create checkboxes ...and on change I call a function passing the value of n of for..next loop
but the n is allway 3

Code: Select all  Expand view

 For n= 1 to len(aFilters)
        @ nRow, nCol CHECKBOX aCheck[n] VAR aFilters[n][1]  ;
               PROMPT aFilters[n][2]  OF  oBox[1] SIZE 150,15 PIXEL;
                 ON CHANGE Filtrare( n, oBrw, oDbf,oBox )

               aCheck[n]:lTransparent:=.t.
               ncol+=160
               if n=3
                  exit
                  endif
              Next

the problem is n is allways 3 , so how I can make to pass the n different for each checkbox ?

[Antonio Linares]

Creating controls in a loop from array is very tricky. It does not work as expected.

Let me show why:

Wrong code:

for n := 1 to 20
@ n * 20, 50 GET aVar[ n ] OF oWnd <clauses>
next n

After this loop the present value of " n " is 21.
When the dialog is activated and controls are to be shown, the value of "n" is 21 and naturally we get runtime error as subscript out of range.

Correct way:

for n := 1 to 20
aGet[ 1 ] := MakeGet( n * 20, 50, aVar, n, oWnd )
next n

ACTIVATE WINDOW ....
//--------------
static function MakeGet( nRow, nCol, aVar, n, oWnd )

local oget

@ nRow, nCol GET oGet VAR aVar[ n ] of oWnd <clauses>

// note this value of "n" remains the same till oGet goes out of scope
// the principle is called "detached locals"

return oGet

[Silvio.Falconi]

Yes
But the valute Is the Number of object
On your test there was allways oget[1]
I have oget[n]

[paquitohm]

Code: Select all  Expand view

For n= 1 to len(aFilters)

b:= {|n|
        @ nRow, nCol CHECKBOX aCheck[n] VAR aFilters[n][1]  ;
               PROMPT aFilters[n][2]  OF  oBox[1] SIZE 150,15 PIXEL;
                 ON CHANGE Filtrare( n, oBrw, oDbf,oBox )
      }
               Eval(b, n)
               
               aCheck[n]:lTransparent:=.t.
               ncol+=160
               if n=3
                  exit
                  endif
              Next

[Silvio.Falconi]

Code: Select all  Expand view

For n= 1 to len(aFilters)

b:= {|n|
        @ nRow, nCol CHECKBOX aCheck[n] VAR aFilters[n][1]  ;
               PROMPT aFilters[n][2]  OF  oBox[1] SIZE 150,15 PIXEL;
                 ON CHANGE Filtrare( n, oBrw, oDbf,oBox )
      }
               Eval(b, n)
               
               aCheck[n]:lTransparent:=.t.
               ncol+=160
               if n=3
                  exit
                  endif
              Next

Compiling 'test.prg'...
test.prg(183) Error E0030 Syntax error "syntax error at '@'"
test.prg(188) Error E0018 EXIT statement with no loop in sight
test.prg(190) Error E0013 NEXT does not match FOR
test.prg(203) Error E0017 Unclosed control structure '{||...}*'
test.prg(203) Error E0017 Unclosed control structure 'FOR*'
test.prg(204) Error E0030 Syntax error "syntax error at '*'"
test.prg(208) Error E0030 Syntax error "syntax error at '*'"
test.prg(358) Error E0030 Syntax error "syntax error at '*'"
8 errors

[nageswaragunupudi]

Mr. paquitohm
Trying to define control this way inside a codeblock will result "variable out of reach" compilation error.

[nageswaragunupudi]

The problem of creating controls using loop variables in a loop is well known and was discussed many times in this forum.
The solution is to create each control in a separate function using the principle of detached locals.
Search for detached locals in this forum.
The sample provided by Mr. Antonio above is the right way to go.
This is a working program using the above principle
Build and run this program in fwh samples folder.

Code: Select all  Expand view

#include "fivewin.ch"

REQUEST DBFCDX

function Main()

   local oDlg, oBrw
   local cFilter  := ""
   local aFilters := { { .f., "AGE>40" }, { .f., "STATE='NY'" }, { .f., "MARRIED" } }
   local aCheck[ 3 ], n
   local nRow  := 40
   local nCol  := 40

   USE CUSTOMER NEW SHARED VIA "DBFCDX"

   DEFINE DIALOG oDlg SIZE 600,400 PIXEL TRUEPIXEL

   for n := 1 to Len( aFilters )

      aCheck[ n ] := CreateChk( nRow, nCol, oDlg, aFilters, n )
      aCheck[ n ]:bChange := { || cFilter := ResetFilter( aFilters ), oDlg:Update() }
      aCheck[ n ]:lTransparent := .t.

      nCol  += 150
      if n == 3
         EXIT
      endif
   next

   @  80, 40 SAY { || "FILTER : " + cFilter } SIZE 400, 25 PIXEL OF oDlg CENTER UPDATE

   @ 115, 40 XBROWSE oBrw SIZE -40,-40 PIXEL OF oDlg ;
      DATASOURCE ALIAS() ;
      COLUMNS "ID", "CITY", "STATE", "MARRIED", "AGE" ;
      CELL LINES NOBORDER UPDATE
   oBrw:SetChecks()
   oBrw:CreateFromCode()

   ACTIVATE DIALOG oDlg CENTERED

return nil

static function CreateChk( nRow, nCol, oDlg, aFilters, nIndex )

   local oChk

    @ nRow, nCol CHECKBOX oChk VAR aFilters[ nIndex, 1 ] ;
       PROMPT aFilters[ nIndex, 2 ] SIZE 150,15 PIXEL OF oDlg

return oChk

static function ResetFilter( aFilters )

   local cFilter  := ""
   local af  := {}

   AEval( aFilters, { |a| If( a[ 1 ], AAdd( af, a[ 2 ] ), nil ) } )
   cFilter  := FW_ArrayAsList( af, " .AND. " )

   if Empty( cFilter )
      SET FILTER TO
   else
      SET FILTER TO &cFilter
   endif
   GO TOP

return cFilter

[paquitohm]

Mr. paquitohm
Trying to define control this way inside a codeblock will result "variable out of reach" compilation error.

Hi to all,

That's right, mr. nageswaragunupudi
IMHO something is wrong in harbor codeblocks because SI should function at least as a LOCAL variable.

The problem is in the double codeblock generated by the fivewin.ch preprocessor, but which harbour, as I commented above, does not know how to solve even though it is helped with the LOCAL

All this quite limits the use of extended codeblocks with commands

Code: Select all  Expand view

For n= 1 to len(aFilters)

b:= {|nParam|

        LOCAL n:= nParam
        @ nRow, nCol CHECKBOX aCheck[n] VAR aFilters[n][1]  ;
               PROMPT aFilters[n][2]  OF  oBox[1] SIZE 150,15 PIXEL;
                 ON CHANGE Filtrare( n, oBrw, oDbf,oBox )
      }
               Eval(b, n)
               
               aCheck[n]:lTransparent:=.t.
               ncol+=160
               if n=3
                  exit
                  endif
              Next

Regards

[Marc Venken]

This is a interesting sample for filtering....

Mr. Rao,

Would you please be so kind to enhance this sample so that there is a second combobox selecting ages like (20 - 40 - 50 etc)
and state like (NY, WY etc) Any small sample with more combo's will de ok. Please use the array's as data because I want to fill
the arrys with data from my xbrwowse dbf filter settings.

v Age v State
>20 NY
v>30 <WY
>40

How good will it look that when Age is selected the extra combo is show and when not, no combo.

[Silvio.Falconi]

The problem of creating controls using loop variables in a loop is well known and was discussed many times in this forum.
The solution is to create each control in a separate function using the principle of detached locals.
Search for detached locals in this forum.
The sample provided by Mr. Antonio above is the right way to go.
This is a working program using the above principle
Build and run this program in fwh samples folder.

Code: Select all  Expand view

#include "fivewin.ch"

REQUEST DBFCDX

function Main()

   local oDlg, oBrw
   local cFilter  := ""
   local aFilters := { { .f., "AGE>40" }, { .f., "STATE='NY'" }, { .f., "MARRIED" } }
   local aCheck[ 3 ], n
   local nRow  := 40
   local nCol  := 40

   USE CUSTOMER NEW SHARED VIA "DBFCDX"

   DEFINE DIALOG oDlg SIZE 600,400 PIXEL TRUEPIXEL

   for n := 1 to Len( aFilters )

      aCheck[ n ] := CreateChk( nRow, nCol, oDlg, aFilters, n )
      aCheck[ n ]:bChange := { || cFilter := ResetFilter( aFilters ), oDlg:Update() }
      aCheck[ n ]:lTransparent := .t.

      nCol  += 150
      if n == 3
         EXIT
      endif
   next

   @  80, 40 SAY { || "FILTER : " + cFilter } SIZE 400, 25 PIXEL OF oDlg CENTER UPDATE

   @ 115, 40 XBROWSE oBrw SIZE -40,-40 PIXEL OF oDlg ;
      DATASOURCE ALIAS() ;
      COLUMNS "ID", "CITY", "STATE", "MARRIED", "AGE" ;
      CELL LINES NOBORDER UPDATE
   oBrw:SetChecks()
   oBrw:CreateFromCode()

   ACTIVATE DIALOG oDlg CENTERED

return nil

static function CreateChk( nRow, nCol, oDlg, aFilters, nIndex )

   local oChk

    @ nRow, nCol CHECKBOX oChk VAR aFilters[ nIndex, 1 ] ;
       PROMPT aFilters[ nIndex, 2 ] SIZE 150,15 PIXEL OF oDlg

return oChk

static function ResetFilter( aFilters )

   local cFilter  := ""
   local af  := {}

   AEval( aFilters, { |a| If( a[ 1 ], AAdd( af, a[ 2 ] ), nil ) } )
   cFilter  := FW_ArrayAsList( af, " .AND. " )

   if Empty( cFilter )
      SET FILTER TO
   else
      SET FILTER TO &cFilter
   endif
   GO TOP

return cFilter

Nages,

I use tdatabase and I have modify

 if Empty( cFilter )
      oDbf:Clearfilter()
   else
      odbf:dbsetfilter( cFilter)
   endif


But Not work

then another question

you made

Code: Select all  Expand view

 local aFilters := { { .f., "AGE>40" }, { .f., "STATE='NY'" }, { .f., "MARRIED" } }

But I wish insert the possibily to select the states, the age amd if the end user want married or not married

how I must make ?

[nageswaragunupudi]

Mr Silvio

The main question was about creating controls in for/next loop.
That is answered satisfactorily.

You can take care of the rest yourself

[Silvio.Falconi]

Mr Silvio

The main question was about creating controls in for/next loop.
That is answered satisfactorily.

You can take care of the rest yourself

Nages

the main question was not about creating controls in for/next loop but to passa a value to bchange function

I tried to pass nIndex in the for next loop to bchange and the value is always the same

I made modifies on you sample https://forums.fivetechsupport.com/viewtopic.php?f=3&t=44513&sid=ca68d176cc14f86e1359d15301a5e80f&sid=c0aafd02f5ba6f3455e4d2dd7f46a2b6#p270092

[nageswaragunupudi]

I use tdatabase and I have modify

if Empty( cFilter )
oDbf:Clearfilter()
else
odbf:dbsetfilter( cFilter)
endif


But Not work

It should be simple to change and make it work.
I made these 6 minor changes and it works well.

Code: Select all  Expand view

#include "fivewin.ch"

REQUEST DBFCDX

function Main()

   local oDlg, oBrw
   local cFilter  := ""
   local aFilters := { { .f., "AGE>40" }, { .f., "STATE='NY'" }, { .f., "MARRIED" } }
   local aCheck[ 3 ], n
   local nRow  := 40
   local nCol  := 40
   local oDbf  // 1. Add this line

//   USE CUSTOMER NEW SHARED VIA "DBFCDX"
   oDbf  := TDataBase():Open( nil, "CUSTOMER", "DBFCDX", .t. ) // 2. Replace

   DEFINE DIALOG oDlg SIZE 600,400 PIXEL TRUEPIXEL

   for n := 1 to Len( aFilters )

      aCheck[ n ] := CreateChk( nRow, nCol, oDlg, aFilters, n )
      aCheck[ n ]:bChange := { || cFilter := ResetFilter( aFilters, oDbf ), oDlg:Update() } // 3. add oDbf param
      aCheck[ n ]:lTransparent := .t.

      nCol  += 150
      if n == 3
         EXIT
      endif
   next

   @  80, 40 SAY { || "FILTER : " + cFilter } SIZE 400, 25 PIXEL OF oDlg CENTER UPDATE

   @ 115, 40 XBROWSE oBrw SIZE -40,-40 PIXEL OF oDlg ;
      DATASOURCE oDbf; // ALIAS() ;  // 4. change to oDbf
      COLUMNS "ID", "CITY", "STATE", "MARRIED", "AGE" ;
      CELL LINES NOBORDER UPDATE
   oBrw:SetChecks()
   oBrw:CreateFromCode()

   ACTIVATE DIALOG oDlg CENTERED

return nil

static function CreateChk( nRow, nCol, oDlg, aFilters, nIndex )

   local oChk

    @ nRow, nCol CHECKBOX oChk VAR aFilters[ nIndex, 1 ] ;
       PROMPT aFilters[ nIndex, 2 ] SIZE 150,15 PIXEL OF oDlg

return oChk

static function ResetFilter( aFilters, oDbf ) // 5. add oDbf

   local cFilter  := ""
   local af  := {}

   AEval( aFilters, { |a| If( a[ 1 ], AAdd( af, a[ 2 ] ), nil ) } )
   cFilter  := FW_ArrayAsList( af, " .AND. " )
/*
   if Empty( cFilter )
      SET FILTER TO
   else
      SET FILTER TO &cFilter
   endif
   GO TOP
*/
   oDbf:SetFilter( cFilter ) // 6. change here
   oDbf:GoTop()

return cFilter

[nageswaragunupudi]

I tried to pass nIndex in the for next loop to bchange and the value is always the same

We need to keep in mind at all times, NOT to use loop variables in building code-blocks inside a loop.
Build the code-block in a separate function using the loop variable as one of the parameters of the function.
Please search for detached locals in this forum.

Keeping this principle in mind, I am sure you can yourself modify the program to use the index in bChange also.
For now, I am modifying the above program.

Code: Select all  Expand view

#include "fivewin.ch"

REQUEST DBFCDX

function Main()

   local oDlg, oBrw
   local cFilter  := ""
   local aFilters := { { .f., "AGE>40" }, { .f., "STATE='NY'" }, { .f., "MARRIED" } }
   local aCheck[ 3 ], n
   local nRow  := 40
   local nCol  := 40
   local oDbf

   oDbf  := TDataBase():Open( nil, "CUSTOMER", "DBFCDX", .t. )

   DEFINE DIALOG oDlg SIZE 600,400 PIXEL TRUEPIXEL

   for n := 1 to Len( aFilters )

      aCheck[ n ] := CreateChk( nRow, nCol, oDlg, aFilters, n, oDbf, @cFilter )
      aCheck[ n ]:lTransparent := .t.

      nCol  += 150
      if n == 3
         EXIT
      endif
   next

   @  80, 40 SAY { || "FILTER : " + cFilter } SIZE 400, 25 PIXEL OF oDlg CENTER UPDATE

   @ 115, 40 XBROWSE oBrw SIZE -40,-40 PIXEL OF oDlg ;
      DATASOURCE oDbf;
      COLUMNS "ID", "CITY", "STATE", "MARRIED", "AGE" ;
      CELL LINES NOBORDER UPDATE
   oBrw:SetChecks()
   oBrw:CreateFromCode()

   ACTIVATE DIALOG oDlg CENTERED

return nil

static function CreateChk( nRow, nCol, oDlg, aFilters, nIndex, oDbf, cFilter )

   local oChk

    @ nRow, nCol CHECKBOX oChk VAR aFilters[ nIndex, 1 ] ;
       PROMPT aFilters[ nIndex, 2 ] SIZE 150,15 PIXEL OF oDlg ;
       ON CHANGE ( cFilter := ResetFilter( aFilters, oDbf, nIndex ), oDlg:Update() )

return oChk

static function ResetFilter( aFilters, oDbf, nIndex )

   local cFilter  := ""
   local af  := {}

   ? "you do whatever you want with nIndex = ", nIndex

   AEval( aFilters, { |a| If( a[ 1 ], AAdd( af, a[ 2 ] ), nil ) } )
   cFilter  := FW_ArrayAsList( af, " .AND. " )
   oDbf:SetFilter( cFilter )
   oDbf:GoTop()

return cFilter
 

[Silvio.Falconi]

I tried to pass nIndex in the for next loop to bchange and the value is always the same

We need to keep in mind at all times, NOT to use loop variables in building code-blocks inside a loop.
Build the code-block in a separate function using the loop variable as one of the parameters of the function.
Please search for detached locals in this forum.

Keeping this principle in mind, I am sure you can yourself modify the program to use the index in bChange also.
For now, I am modifying the above program.

Code: Select all  Expand view

#include "fivewin.ch"

REQUEST DBFCDX

function Main()

   local oDlg, oBrw
   local cFilter  := ""
   local aFilters := { { .f., "AGE>40" }, { .f., "STATE='NY'" }, { .f., "MARRIED" } }
   local aCheck[ 3 ], n
   local nRow  := 40
   local nCol  := 40
   local oDbf

   oDbf  := TDataBase():Open( nil, "CUSTOMER", "DBFCDX", .t. )

   DEFINE DIALOG oDlg SIZE 600,400 PIXEL TRUEPIXEL

   for n := 1 to Len( aFilters )

      aCheck[ n ] := CreateChk( nRow, nCol, oDlg, aFilters, n, oDbf, @cFilter )
      aCheck[ n ]:lTransparent := .t.

      nCol  += 150
      if n == 3
         EXIT
      endif
   next

   @  80, 40 SAY { || "FILTER : " + cFilter } SIZE 400, 25 PIXEL OF oDlg CENTER UPDATE

   @ 115, 40 XBROWSE oBrw SIZE -40,-40 PIXEL OF oDlg ;
      DATASOURCE oDbf;
      COLUMNS "ID", "CITY", "STATE", "MARRIED", "AGE" ;
      CELL LINES NOBORDER UPDATE
   oBrw:SetChecks()
   oBrw:CreateFromCode()

   ACTIVATE DIALOG oDlg CENTERED

return nil

static function CreateChk( nRow, nCol, oDlg, aFilters, nIndex, oDbf, cFilter )

   local oChk

    @ nRow, nCol CHECKBOX oChk VAR aFilters[ nIndex, 1 ] ;
       PROMPT aFilters[ nIndex, 2 ] SIZE 150,15 PIXEL OF oDlg ;
       ON CHANGE ( cFilter := ResetFilter( aFilters, oDbf, nIndex ), oDlg:Update() )

return oChk

static function ResetFilter( aFilters, oDbf, nIndex )

   local cFilter  := ""
   local af  := {}

   ? "you do whatever you want with nIndex = ", nIndex

   AEval( aFilters, { |a| If( a[ 1 ], AAdd( af, a[ 2 ] ), nil ) } )
   cFilter  := FW_ArrayAsList( af, " .AND. " )
   oDbf:SetFilter( cFilter )
   oDbf:GoTop()

return cFilter
 

Thanks Nages , I means somethig of this

I insert only a selection ( states)

Code: Select all  Expand view

static function ResetFilter( aFilters, oDbf, nIndex )

   local cFilter  := ""
   local af  := {}

   local cState:= space(25)
   local lMarried:=.f.
   local nAge:=0


   //? "you do whatever you want with nIndex = ", nIndex

   If nIndex==1
      //Selection_Age(@nAge)
      nAge:=40  //sample
      cFilter:= 'AGE<'+ltrim(str(nAge))
       aFilters[1][2]:= cFilter
   elseif nIndex==2
      Selection_State( @cstate )
      cFilter:= 'STATE='+ "'"+cState+"'"
      aFilters[2][2]:= cFilter
    elseif nIndex==3
      // Selection_Married(@lMarried)
       lMarried:=".t." //sample
       cFilter:= 'MARRIED='+ lMarried
       aFilters[3][2]:= cFilter
   endif


  AEval( aFilters, { |a| If( a[ 1 ], AAdd( af, a[ 2 ] ), nil ) } )
   cFilter  := FW_ArrayAsList( af, " .AND. " )
   oDbf:SetFilter( cFilter )
   oDbf:GoTop()

return cFilter
//----------------------------------------------------------------//

 Function  Selection_State( cstate )
    local oList
    local oDlg,oBrw
    local lOk    := .f.

    local nArea := Select()

       olist  := TDataBase():Open( nil, "STATES", "DBFCDX", .t. )
       olist:Gotop()

    DEFINE DIALOG oDlg SIZE 600,400 PIXEL TRUEPIXEL

    @ 115, 40 XBROWSE oBrw SIZE -40,-40 PIXEL OF oDlg ;
      DATASOURCE oList ;
      COLUMNS "CODE", "NAME" ;
      CELL LINES NOBORDER UPDATE

    oBrw:CreateFromCode()

   aEval( oBrw:aCols, { |oCol| oCol:bLDClickData := { || lOk := .T., oDlg:End() } } )

   ACTIVATE DIALOG oDlg CENTERED

   if lOK
       cstate :=oList:code
    Endif

    Select (nArea)
    oList:close()

    return nil
//-----------------------------------------------------------------//

 

so the end user can select what he needs to search for, the procedure rewrites the filters and executes them

when you click on a checkbox for example the states is activated true and you can select the state but when you click again from true it becomes false and should not ask you to select the state