Need to Update a file after a DBGrid Double-Click - delphi

Question

I seem to have a mental block with this one.
I need to save recent changes to a Record. I am doing it OK with buttons for "New" "Edit" "Post" "Next" etc but when a user double-clicks a DBGrid, it is now too late to make changes as the DBGrid selection has moved the database cursor to the selected record.
I can't use AutoUpdate as the data that may have been changed is not something the user would have directly entered, it is a value that is changing all the time.
I'll try to describe it better: While the user is reading a Test-page, a timer is counting down or up. When they click the "Next" or "Prior" buttons I can save the timer setting. But, if they Double-Click the DBGrid I have no way of first changing the current Record before the selection moves to the clicked-Record.
I tried using the
Procedure TForm1.tblTestOnBeforeScroll(...
begin
tblTest.Edit;
tblTest.FieldByName('TimerCt').AsInteger:=ClockCtr;
tblTest.Post;
end;
But, that crashed the database, not surprisingly, but I thought I would give it a try before asking here.
How do I deal with the current record? I do not want to disallow the double-click if possible as it seems nice and intuitive for the user.

Answer 1

I'm afraid that what you do on DBGrid is a wrong in concept action.
Key point is DBGrid is a data aware control. So everything you do on it must based on it's datasource then it's dataset.
There is a DblClick event on TDBgrid. But still you have to check it's dataset to see what record is active.
The code you shown above clearly lead you to an endless loop.
When you doing a scroll, the dbgrid will call OnBeforeScroll event, moving the active record
and call OnAfterScroll. Your OnBeforeScroll code does an data update. Then dbgrid abort its operation cause of data change. Then after data update, it try to scroll again, and the data change happen again. Endless loop happen here.
best regard

Answer 2

Apologies in advance if I'm misunderstanding you, but it seems to me that either the premise of your question is wrong or there is something relevant you haven't told us about what you're doing. Please try the following:
If you don't have one already, please temporarily add a DBNavigator to your form and connect it to the same DataSource as your DBGrid. The point of doing this is so that you can more clearly see what's going on.
Then, in your DBGrid's Options, set dgEditing to True.
Finally, comment out or disable your BeforeScroll handler, save and run your program.
Now, click once in some cell in your DBGrid that contains a value which it's ok to change. Click it a second time so that it selects the value in the cell rather than the cell per se.
Make some change to the cell value, but do nothing else for the time being. You should notice that a) the current record indicator of the DBGrid has changed from a black triangle to an I-Beam graphic, like ][ and b) that the tick and cross buttons of the DBNavigator are now enabled.
Now, without doing anything else on the form, click in another row of the DBGrid. You should find that a) the change to what was the current record in step 5 has been saved and b) the current row indicator reverts to the black triangle and the DBNav's tick and cross buttons are disabled.
(If you don't get the behaviour I've just described, create a minimal new project and try that instead, as some other change you've made in your existing project may be interfering with it).
What I've described in 5 & 6 is the default behaviour of a DBGrid and insofar as I understand your q, that seems to be the behaviour you're trying to achieve. If that's not the behaviour you want, please explain exactly how what you do want differs. It's not clear to me where the user double-clicking on the grid comes into your q, except that that action may move the dataset's cursor (if the dbl-click is on a different row than the current one), but as the default DBGrid behaviour will save changes to the current row before it moves the dataset's cursor, it will do what you seem to want automatically.
Btw, what "AutoUpdate" do you mean? Did you mean TDataSource's AutoEdit property?