dlDlistToIcon result is not usable in a form

I added some code around it so that I could debug the problem. The issue was in this line:

arrayGenForm->arrayGenTopFrame->summaryLayout->iconLabel->labelIcon=icon

It should have been:

arrayGenForm->arrayGenTopFrame->summaryLayout->iconLabel->value=icon

Here's the modified code (with the additional fields to help me debug):

dl=dlMakeDisplayList()
penTable=dlMakePenTable(5)
dlSetPenTable(dl penTable)
colorIndex=hiMatchColor(nameToColor("red"))
dlSetPenColor(1 colorIndex penTable)
dlSetPenFillStyle( 1 "SolidFill" penTable)
dlAddBox(dl 1 list(0 0) list(200 200) 'bigBox)
dlAddBox(dl 4 list(20 20) list(180 180) 'littleBox)
/* just checking what the icon would have looked like
let(((w 50) (h 30))
  dlClearDisplayList(dl)
  dlAddBox(dl 1 list(0 0) list(round(w) round(h)) 'extentBox)
)
*/

icon=dlDlistToIcon(dl 200 200)
enterLayout=hiCreateHorizontalBoxLayout('enterLayout
  ?frame "Debug"
  ?margins list(50 20 50 20)
  ?spacing 50
  ?items list(
    hiCreateFloatField(
      ?name 'width
      ?prompt "Width:"
    )
    hiCreateFloatField(
      ?name 'height
      ?prompt "Height:"
    )
    hiCreateButton(
      ?name 'updateIt
      ?buttonText "Update"
      ?callback "updateIcon()"
      )
  )
)

summaryLayout=hiCreateHorizontalBoxLayout('summaryLayout
  ?frame "Summary"
  ?margins list(50 20 50 20)
  ?spacing 50
  ?items list(
    hiCreateFloatField(
      ?name 'totalWidth
      ?prompt "Total Width:"
      ?editable 'nil
    )
    hiCreateFloatField(
      ?name 'totalHeight
      ?prompt "Total Height:"
      ?editable 'nil
    )
    hiCreateLabel(
      ?name 'iconLabel
      ?labelIcon icon
    )
  )
)

sep1=hiCreateSeparatorField(?name 'sep1)
sep2=hiCreateSeparatorField(?name 'sep2)

arrayGenTopFrame=hiCreateFormLayout('arrayGenTopFrame
  ?frame "Top Frame"
;?items list(coreLayout sep1 ewLayout nsLayout cornerLayout sep2 summaryLayout)
  ?items list(sep1 enterLayout sep2 summaryLayout)
)

hiCreateLayoutForm('arrayGenForm "arrayGen Compound Array Generator" arrayGenTopFrame
  ?callback 'arrayGenFormCB
  ?minSize 800:10
)

procedure(coreLCVCB()
  size=getCellSize(
    arrayGenForm->arrayGenTopFrame->coreLayout->coreLCVLayout->coreL->value
    arrayGenForm->arrayGenTopFrame->coreLayout->coreLCVLayout->coreC->value
    arrayGenForm->arrayGenTopFrame->coreLayout->coreLCVLayout->coreV->value
  )
  arrayGenForm->arrayGenTopFrame->coreLayout->coreWidthLayout->coreCellWidth->value=car(size)
  arrayGenForm->arrayGenTopFrame->coreLayout->coreHeightLayout->coreCellHeight->value=cadr(size)
  ddsUpdateSyncWithForm()
  updateIcon()
)

procedure(updateIcon()
  let((lib cell view file w h icon)
    /*
    lib=arrayGenForm->arrayGenTopFrame->coreLayout->coreLCVLayout->coreL->value
    cell=arrayGenForm->arrayGenTopFrame->coreLayout->coreLCVLayout->coreC->value
    view=arrayGenForm->arrayGenTopFrame->coreLayout->coreLCVLayout->coreV->value

    w=arrayGenForm->arrayGenTopFrame->coreLayout->coreWidthLayout->coreTotalWidth->value
    h=arrayGenForm->arrayGenTopFrame->coreLayout->coreHeightLayout->coreTotalHeight->value
    */
    w=arrayGenForm->width->value
    h=arrayGenForm->height->value

    ; method 1: this does not work - the image stays blank regardless of cell selection 
    dlClearDisplayList(dl)
    dlAddBox(dl 1 list(0 0) list(round(w) round(h)) 'extentBox)
    icon=dlDlistToIcon(dl 200 200)
    printf("setting icon: %L w=%L h=%L\n" icon w h)
    ; THIS LINE WAS INCORRECT...
    ;arrayGenForm->arrayGenTopFrame->summaryLayout->iconLabel->labelIcon=icon
    arrayGenForm->arrayGenTopFrame->summaryLayout->iconLabel->value=icon

    ; method 2: this works - the image is refreshed every time you select a different cell
    ; whether you use hiLoadIconFile or hiLoadImageFile
    ; file=ddGetObj(lib cell view hiGetThumbnailFilename())->readPath
    ; when(file
    ; icon=hiLoadIconFile(file 200 200)
    ; printf("setting icon: %L\n" icon)
    ; arrayGenForm->arrayGenTopFrame->summaryLayout->iconLabel->value=icon
    ; )
  )
)

; to test
; hiDisplayForm(arrayGenForm)

When initially displaying the form, it appears like this (so the display list icon is clearly being used):

If I enter some values in the Debug fields and hit Update, the form updates:

Here's a second update:

So I think it's just down to the statement above. I didn't quite get what  you meant about "just a black box" - for me before this tweak to the code, the icon remained as it did initially (the first image above).

Merry Christmas and a Happy New Year!

Regards,

Andrew.

Thanks, that works - I thought I had tried that before, but, clearly I had not!