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Remy Lebeau (TeamB)
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 Posted: Mon Aug 18, 2003 11:27 pm Post subject: Re: how to manage focus on an aggregate (composite) componen |
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"Dennis Jones" <djones (AT) nospam (DOT) com> wrote
| Quote: | I have an aggregate component which is made up of several
sub-components, the most critical of which are a string grid and
a scroll bar. When I click on the scroll bar, it recevies (and keeps)
the focus, so all keyboard input starts going to it.
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Any particular reason why you are not simply using the TStringGrid's native
scrollbars?
| Quote: | How can I keep the focus on the string grid, and yet still allow
mouse events to occur on the scroll bar?
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Have you tried shifting the focus back to the TStringGrid after the mouse
button has been released?
Gambit
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Dennis Jones
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| Posted: Tue Aug 19, 2003 12:44 am Post subject: Re: how to manage focus on an aggregate (composite) componen |
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"Dennis Jones" <djones (AT) nospam (DOT) com> wrote
| Quote: |
"Remy Lebeau (TeamB)" <gambit47 (AT) yahoo (DOT) com> wrote in message
news:3f415f5b$1 (AT) newsgroups (DOT) borland.com...
"Dennis Jones" <djones (AT) nospam (DOT) com> wrote in message
news:3f414ef2$1 (AT) newsgroups (DOT) borland.com...
Have you tried shifting the focus back to the TStringGrid after the
mouse
button has been released?
No. I thought about it though. I figured doing that was a "hack" and
that
there must be a better, more standard (and elegant) way to handle this
situation. If that is what I have to do, however, then that is what I will
do.
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Oops...TScrollBar doesn't make the OnMouseUp event visible. Any
suggestions?
- Dennis
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Remy Lebeau (TeamB)
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| Posted: Tue Aug 19, 2003 2:18 am Post subject: Re: how to manage focus on an aggregate (composite) componen |
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"Dennis Jones" <djones (AT) nospam (DOT) com> wrote
| Quote: | Oops...TScrollBar doesn't make the OnMouseUp event visible. Any
suggestions?
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Simply derive a new class from TScrollBar and promote the event to
public/__published manually:
class TMyScrollBar
{
__published:
__property OnMouseUp;
};
Then create an instance of your derived class instead of TScrollBar itself.
Gambit
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system ([url]http://www.grisoft.com)[/url].
Version: 6.0.510 / Virus Database: 307 - Release Date: 8/14/03
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Dennis Jones
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| Posted: Tue Aug 19, 2003 2:39 am Post subject: Re: how to manage focus on an aggregate (composite) componen |
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"Remy Lebeau (TeamB)" <gambit47 (AT) yahoo (DOT) com> wrote
| Quote: |
"Dennis Jones" <djones (AT) nospam (DOT) com> wrote in message
news:3f417306$1 (AT) newsgroups (DOT) borland.com...
Simply derive a new class from TScrollBar and promote the event to
public/__published manually:
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Yeah, I thought of that too. I guess I usually have the right idea, just
not always sure if it is the most sound approach.
Thanks Remy.
- Dennis
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Dennis Jones
Guest
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| Posted: Tue Aug 19, 2003 4:47 am Post subject: Re: how to manage focus on an aggregate (composite) componen |
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"Remy Lebeau (TeamB)" <gambit47 (AT) yahoo (DOT) com> wrote
| Quote: |
"Dennis Jones" <djones (AT) nospam (DOT) com> wrote in message
news:3f417306$1 (AT) newsgroups (DOT) borland.com...
Simply derive a new class from TScrollBar and promote the event to
public/__published manually:
class TMyScrollBar
{
__published:
__property OnMouseUp;
};
Then create an instance of your derived class instead of TScrollBar
itself. |
Well, it was a good idea, but it doesn't work. The OnMouseUp event gets
called for right and middle mouse button clicks, but not for left mouse
button clicks. I'm guessing that the WM_LBUTTONDOWN/WM_LBUTTONUP messages
are handled by the Windows scrollbar control and are therefore never heard
from again (a left-mouse-click black hole?).
However, I did find a solution that works. I use TScrollBar's OnChange
event to set the focus back to the grid. This was initially problematic
because I kept getting "control has no parent window" errors during my
component's construction (whether at design time or runtime). But if I
assign the OnChange event handler very late in the component's constructor
(after a call to Loaded()), that problem goes away. And the OnChange event
seems to give me what I needed to handle mouse events in the scrollbar and
still give the focus back to the grid when I'm done.
- Dennis
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