Subject Re: Control passing back and fro in a form sub routine
From Milind Nighojkar <milinigh@yahoo.com>
Date Wed, 26 Jul 2023 18:33:39 -0400
Newsgroups dbase.getting-started

Your suggestion noted on decribing  the issue...

Thanks for your solution....

Mervyn Bick Wrote:

> On 2023/07/26 03:19, Milind Nighojkar wrote:
 >
> > Mevin to clarify myslef I want to build scenerio on your example itself
 > >
> > You have used set procedure to square.prg. I want to put something like this
 > >
> > function square(nVal)
 > >       local retVal
 > >       do while nVal < = 5
 > >            retVal = nVal*nVal
 > >            *Display nVal onto the form and come baclk
 > >
> >            nVal = nVal+1
 > >        endd
 > >    return retVal
 > >
> > here I want to go to square.form and display nVal onto the
 > >            *form and come back for next nVal
 > >
> > Hope I clarify
 > >
>
> Milind (and Akshat and anyone else out there :-) ), it helps if you
> quote only the relevant parts from a message when you reply but it is
> counter productive to quote the entire message.  Using Web-News makes it
> worse as it includes the text from any attachements as well.  Having to
> scroll through literally pages of meaningless text to get to your input
> is a nuisance.  Please take the time to delete irrelevant text.
 >
> Once again, there is more than one way to address your problem and it
> really depends on how you want to display the returned values.  A
> function returns 1 value but this can be an array so you could do
> something like the following..
 >
> function square1(nVal)
 >     local n, nVal, aArray
 >     aArray = new array()
 >     for n = nVal to nVal + 4 //will calculate 5 values
 >       aArray.add(n*n)
 >     next
 >     return aArray
 >
>
> In your form, say in a pushbutton's onClick event handler,
 >
>       form.squares = square1(nStartvalue)
 >
> This would place the values calculated in the program in an array stored
> in a user-defined property of the form.  It would then be up to you to
> write code in the form to display the values in the array.  See
> squares1.wfm
 >
> It is, however, more usual to pass the values to be processed to the
> function one by one and deal with displaying them as each value is
> returned.  See squares2.wfm  In this case the loop to increment the
> values to be calculated is in the form rather than in the function.
 >
> Neither way is "right" and neither way is "wrong" although my preference
> is to do things "one by one" with multiple calls to the function.  By
> making the decision in the form of how many values to calculate gives
> the programmer far more control.  If, after you have used the function
> that returns 5 values in several forms, you find you now need 7 values
> there is no problem if the number of iterations is detemined in
> individual forms.  If you have to change the function this may cause
> problems in forms expecting only 5 values.  It means you may need to
> write a new function.  Having two fuctions that are almost, but not
> completely, identical is not good programming practice.
 >
> Mervyn.
 >
>
>
>
>
>
> function square1(nVal)
 >    local n, nVal, aArray
 >    aArray = new array()
 >    for n = nVal to nVal + 4
 >      aArray.add(n*n)
 >    next
>    return aArray** END HEADER -- do not remove this line
 > //
 > // Generated on 2023-07-26
 > //
 > parameter bModal
 > local f
 > f = new square2Form()
 > if (bModal)
 >    f.mdi = false // ensure not MDI
 >    f.readModal()
 > else
 >    f.open()
 > endif
 >
> class square2Form of FORM
 >    with (this)
 >       onOpen = class::FORM_ONOPEN
 >       height = 16.0
 >       left = 7.4286
 >       top = 1.6818
 >       width = 67.5714
 >       text = ""
 >    endwith
 >
>    this.PUSHBUTTON1 = new PUSHBUTTON(this)
 >    with (this.PUSHBUTTON1)
 >       onClick = class::PUSHBUTTON1_ONCLICK
 >       height = 2.0909
 >       left = 13.0
 >       top = 7.4091
 >       width = 15.2857
 >       text = "Calculate squares"
 >    endwith
 >
>    this.EDITOR1 = new EDITOR(this)
 >    with (this.EDITOR1)
 >       height = 8.1818
 >       left = 37.2857
 >       top = 3.5909
 >       width = 20.0
 >       value = ""
 >    endwith
 >
>
>    function ENTRYFIELD1_onGotFocus()
 >       this.value = ''
 >       form.entryfield2.value = ''
 >       return
 >
>    function PUSHBUTTON1_onClick()
 >      nStart = 3
 >      form.squares = square1(nStart)
 >      crlf = chr(13)+chr(10)
 >       for n = 1 to 5
 >            form.editor1.value += (n-1+nStart)+'  * '+(n-1+nStart)+' = '+ form.squares[n]+CRLF
 >       next
 >       return
 >
>    function form_onOpen()
 >       set procedure to square1.prg
 >       return
 >
> endclass
 >
> ** END HEADER -- do not remove this line
 > //
 > // Generated on 2023-07-26
 > //
 > parameter bModal
 > local f
 > f = new square2Form()
 > if (bModal)
 >    f.mdi = false // ensure not MDI
 >    f.readModal()
 > else
 >    f.open()
 > endif
 >
> class square2Form of FORM
 >    with (this)
 >       onOpen = class::FORM_ONOPEN
 >       height = 16.0
 >       left = 7.4286
 >       top = 1.6818
 >       width = 67.5714
 >       text = ""
 >    endwith
 >
>    this.PUSHBUTTON1 = new PUSHBUTTON(this)
 >    with (this.PUSHBUTTON1)
 >       onClick = class::PUSHBUTTON1_ONCLICK
 >       height = 2.0909
 >       left = 13.0
 >       top = 7.4091
 >       width = 15.2857
 >       text = "Calculate squares"
 >    endwith
 >
>    this.EDITOR1 = new EDITOR(this)
 >    with (this.EDITOR1)
 >       height = 8.1818
 >       left = 37.2857
 >       top = 3.5909
 >       width = 20.0
 >       value = ""
 >    endwith
 >
>
>    function ENTRYFIELD1_onGotFocus()
 >       this.value = ''
 >       form.entryfield2.value = ''
 >       return
 >
>    function PUSHBUTTON1_onClick()
 >      crlf = chr(13)+chr(10)
 >      nStart = 3
 >       for n = nStart to 4+nStart
 >            form.editor1.value += str(n,2)+'  * '+str(n,2)+' = '+ square(n)+CRLF
 >       next
 >       return
 >
>    function form_onOpen()
 >       set procedure to square.prg
 >       return
 >
> endclass
 >