Solved

Automatic scrolling when dragging over TScrollBox (Delphi)

Posted on 2007-11-29
3
998 Views
Last Modified: 2010-04-21
In my Delphi application I have a TScrollBox with only the vertical scroll bar enabled.

When the scroll box is too small for its contents then the vertical scroll box appears automatically - that's fine.

I would like the scrollbox to automatically scroll up and down as necessary when the user drags an object over it (so they can find the right place to drop it).

Does anyone know how to achieve this?
0
Comment
Question by:plumothy
  • 2
3 Comments
 
LVL 21

Expert Comment

by:ziolko
ID: 20372282
try this:

procedure TForm1.ScrollBox1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
var calcX, calcY: Integer;
begin
  //calcX, calcY calculate how you want it to scroll
  ScrollBox1.ScrollBy(calcX, calcY);
end;


ziolko.
0
 
LVL 21

Accepted Solution

by:
ziolko earned 500 total points
ID: 20372548
...or even bettetr use ScrollBox.VertScrollBar.Position something like:

procedure TForm1.ScrollBox1DragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  Accept := Source is TTreeView;
  if Y < 15 then
    ScrollBox1.VertScrollBar.Position := ScrollBox1.VertScrollBar.Position - 8
  else if Y > ScrollBox1.Height  - 15 then
    ScrollBox1.VertScrollBar.Position := ScrollBox1.VertScrollBar.Position + 8;
end;

ziolko.
0
 

Author Closing Comment

by:plumothy
ID: 31411609
Perfect, thanks
0

Featured Post

3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
QRReport  TQrmemo vertical stretching 1 46
Firemonkey webbrowser scrollbars ? 1 39
Graphics32 under Delphi 10.1 Berlin 2 65
Multi-layered image in FireMonkey 9 34
The uses clause is one of those things that just tends to grow and grow. Most of the time this is in the main form, as it's from this form that all others are called. If you have a big application (including many forms), the uses clause in the in…
Have you ever had your Delphi form/application just hanging while waiting for data to load? This is the article to read if you want to learn some things about adding threads for data loading in the background. First, I'll setup a general applica…
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…
Nobody understands Phishing better than an anti-spam company. That’s why we are providing Phishing Awareness Training to our customers. According to a report by Verizon, only 3% of targeted users report malicious emails to management. With compan…

773 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question