Using a subform to provide a summary is pretty heavy, structurally. Why don't you show the summary with a multiline text editor instead? Much lighter and easier.

Here's what I came up with - it works!  But I'll gladly take suggestions on how to improve it.  Many thanks, Hammer.

AddNewLineItem:: On Element Entry

var vTemp as Int
var vLine as String
var vItemNum as String
var vItemQty as String
var vItemUoM as String
var vItemDesc as String
var vSumView1 as String

vItemNum = ItemNum
vItemQty = ItemQty
vItemUoM = ItemUoM
vItemDesc = ItemDesc


     If (@Mode() = 0) or (@Mode() = 1)
           
           {  // add a string array line to SummaryView1, create a new POLines record, throwFocus(ItemNum)
              vLine = vItemNum + " ** " +  vItemQty + " " + vItemUoM + " ** " +  vItemDesc + @Newline() + "==========" + @Newline()
              vSumView1 = @FormFieldValue("Purch", "SummaryView1", 0)
              vSumView1 = @AppendStringArray(vSumView1, vLine)
              FormFieldValue("Purch", "SummaryView1", 0, vSumView1)
              //WriteLn(vLine)
              vTemp = @CreateNewRecord()
              ThrowFocus(ItemNum)
           }

Bob_Hansen wrote on Mar 10^th, 2009 at 3:34am:

Since he wants it on the same parent at the same time, synching issues can present. Text is the safer choice in this case.

Main form "Purch" ... Subform "POLines" ... SummaryView is a text editor field on main form "Purch" ...

I'm having trouble building my SummaryView (text editor box) of PO line items placed.  The following code builds the summary view just fine, but after the 2nd line item is inserted, the programming throws the focus back to the first or second POLines record, instead of the 'next' record to be placed (3rd record, then 4th record, then ...) .  If I /* out this code, then the POLines programming works perfectly, taking me from the 1st record to the 2nd, then the 3rd, then the 4th, etc), but of course I don't get a summaryview field that's filled with line items ordered.

           vLine = vItemNum + " ** " +  vItemQty + " " + vItemUoM + " ** " +  vItemDesc + @Newline() + "==========" + @Newline()
           vSumView = @FormGetValues("Purch", "SummaryView")
           vSumView1 = vSumView + vLine
           vSumView = vSumView1
           FormFieldValue("Purch", "SummaryView", 0, vSumView)
           
           If ((@Mode() = 1) and (POLinesYN = 1) and (@FormViewType("") = 0))
           {
                 throwFocus(NextRecord1)
           }

The following code works great.  It is invoked as the PO is being built (but not 'placed' yet), line item by line item.  It plugs each line item into a SummaryView1 text editor field on PURCH that shows a list of items that have been entered into the PO, but not called in yet. 

     If (@Mode() = 0) or (@Mode() = 1)
           
           {  // add a string array line to SummaryView1, create a new POLines record, throwFocus(ItemNum)
              vLine = vItemNum + " ** " +  vItemQty + " " + vItemUoM + " ** " +  vItemDesc + @Newline() + "==========" + @Newline()
              vSumView1 = @FormFieldValue("Purch", "SummaryView1", 0)
              vSumView1 = @AppendStringArray(vSumView1, vLine)
              FormFieldValue("Purch", "SummaryView1", 0, vSumView1)
              //WriteLn(vLine)
              vTemp = @CreateNewRecord()
              ThrowFocus(ItemNum)
           }

I suspect the problem is that this code that works is always working on the 'sole' record that is being added, while the above above code that isn't working is throwing the focus back to the 1st record in the set.  My stumbling block is in not knowing how to tell the focus to go to the next record in the set that has not been placed yet (the next record in which the POLinesYN field is blank)