OK, I have figured out when ScrollNextRow() fails (by sometimes jumping instead of scrolling one row): it seems to be when there is a group break with a group header. I have submitted a small sample like that to Appeon as a bug: https://www.appeon.com/standardsupport/search/view?id=7282

Hi Dan,

scrollPerRow = Int(scrollMax / dw.RowCount())

^ this calculation is actually incorrect. While VerticalScrollMaximum is indeed the maximum scroll position, it is not usually possible to scroll so far that the last row is also the first row on page. Thus, the divisor will be off by the number of rows displayed on the last possible page of the DW. The result might be just accurate enough if you have a large enough number of rows in your DW but on low rowcounts it will be *way* off.
Now we could calculate the scroll value per row this way but this is much easier to solve because the scroll value per row is actually equivalent to DataWindow.Detail.Height.

Hence, this code should do the trick:

long scrollMax
long detailHeight

scrollMax = Integer( dw.Describe( "DataWindow.VerticalScrollMaximum" ) )
detailHeight = Integer( dw.Describe ( "DataWindow.Detail.Height" ) )
dw.Modify( "DataWindow.VerticalScrollPosition='" + String( min( scrollMax , ( row - 1 ) * detailHeight ) ) + "'" )

The check for values above scrollMax is optional. From my experience, trying to set VerticalScrollPosition to anything above the VerticalScrollMaximum will just set it to the maximum instead. But safety first, I guess. :) 

But if you'd like, you could reduce the whole thing to a one-liner:

dw.Modify( "DataWindow.VerticalScrollPosition='" + String( ( row - 1 ) * Integer( dw.Object.DataWindow.Detail.Height ) ) + "'" )

This will obviously fall apart if there's any dynamic resizing or AutoHeight going on, though.

Hi Dan,

Here's a workaround that I've used:

// Assume that ll_desiredRow is the row you want to appear at the top of the DW control

long ll_row

// First get the row on the page to minimize the number of iterations of the loop below

dw_list.scrollToRow(ll_desiredRow)

ll_row = long(dw_list.describe("datawindow.firstRowOnPage"))

DO WHILE ll_row <> ll_desiredRow

  dw_list.scrollNextRow()

  ll_row = long(dw_list.describe("datawindow.firstRowOnPage"))

LOOP

OK finally came up with a solution after a hint from Mike Searer offline (thanks!) and using something I had been reluctant to use because it seemed so unconnected from the actual rows:

// make row number "row" the first shown row in the DW, if possible
DWObject dwo
long scrollPos, scrollMax, scrollPerRow, firstRow, i

dwo = dw.Object
dw.ScrollToRow(row)

scrollPos = Integer(dwo.DataWindow.VerticalScrollPosition)
scrollMax = Integer(dwo.DataWindow.VerticalScrollMaximum)
scrollPerRow = Int(scrollMax / dw.RowCount())
firstRow = Integer(dwo.DataWindow.FirstRowOnPage)

for i = firstRow to row + 1
    scrollPos += scrollPerRow
    if scrollPos < 1 then EXIT
    dwo.DataWindow.VerticalScrollPosition = String(scrollPos)
    // make sure we haven't gone too far
    if row < Integer(dwo.DataWindow.FirstRowOnPage) then
        dwo.DataWindow.VerticalScrollPosition = String(scrollPos - scrollPerRow)
        EXIT
    end if
next

Hi Dan;

  Have you tried ... for example, say the first row on the last page, as follows;

• String ls_row
• DC.ScrollToRow ( DC.RowCount() )
• ls_row = DC.Describe("DataWindow.FirstRowOnPage")
• DC.ScrollToRow ( Long (ls_row) )

Regards ... Chris

If you know how many rows fit in the control, you could calculate the row number to pass to ScrollToRow.