asked on

Scrolling a Memo by 5 lines using code

I want to scroll a memo component to a particular line, say, line 5 -
and when I try

memo1.scrollby(0,10);

I get the text scrolling (but not by a complete line - so I get a blur
effect). Obviously I need to replace the 10 by the font height in
pixels (multiplied by the number of lines to scroll by).

But the problem seems deeper - when I do a
memo1.repaint;
the effect of the scroll goes away viz. the scroll has not 'really'
happened - it is just a visual illusion.

I obviously need to send a EM_ message of some sort, and found the
following routine which I experimentally HACKED:

procedure ScrollMemoToTop(Memo: TCustomMemo);
var
topLine : integer;
begin
topLine := SendMessage(Memo.Handle, EM_GETFIRSTVISIBLELINE,
0, 0);

// Experimentally override with the line to scroll to
topLine := 5;

SendMessage(Memo.Handle, EM_LINESCROLL,
0, MAKELONG(word(-topLine),0));
end;

But this doesn't seem to actually do anything. Can anyone help me out
here? I just want to be able to simply say
memo1.scrollToLine(5);

--
Andy Bulka
WindowWare Multimedia

ronit051397

When you scroll to line 5 you want to see it as the first line displayed in the memo?

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mirek071497

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abulka

ASKER

Thanks. The actual problem in my code was the minus sign

SendMessage(Memo.Handle, EM_LINESCROLL,
0, MAKELONG(word(-topLine),0));

which should have been removed. I'm not sure why the original code I based the algorithm on had it there. Anyway - problem fixed.