TDBControlGrid question/Issue

[patyigit]

Hi !

Theoretically, can TDBControlGrid be used with other DataSets (e.g. Zeos8) and not just IBX ?
I have a project that was implemented with Zeos8, now I need to make a small extension, TDBControlGrid would be ideal for this.
I created the form, everything is nice and good, but I can't create a new record inside the TDBControlGrid, it only flashes one and jumps back to the first record.

I tried the following, but it doesn't work either :

procedure TForm.DBNavigator1Click(Sender: TObject; Button: TDBNavButtonType);
begin
  if Button = nbInsert then begin
    ZQuery.Append;
    ZQuery.Post;
    ZQuery.Last;
  end;
end;

TDBControlGrid.Options := [dgpIndicator] // dgpDisableInsert is not in it !

[patyigit]

I forgot to mention that ZQuery.OnNewRecord populates the appropriate fields with data ...

[patyigit]

Also forgot to mention the Database is MySQL

[MWASoftware]

In principle, TDBControlGrid should work with any database driver; it has no IBX dependencies.

Your problem is probably due to processing the TDBNavigator event. When you click on the insert button, it should always call the TDataset.Insert method itself. There is no need to override the event and call append.

[patyigit]

Yes, for the first and many attempts I did not modify the TDBNavigator button event.
What I feel is that when opening a new record (insert or append) the data link interrupts the insert !
There is some difference between the behavior of the IBX and Zeos8 dataset cases, because it behaves well with IBX.
It is easy to test, you need a MySql table, TZQuery, TDatasource, TDBControlGrid, TDBNavigator, ...

[MWASoftware]

Using Tdataset.insert used to be a problem with IBX. That is until I brought in the new buffer management strategy. Maybe Zeos has a similar problem with insert. Try using a separate TButton to call Append and don't call post. That should be a separate action.

[patyigit]

I tried the suggested method, but unfortunately the result is the same, it just flashes as if there is a new record for a moment, but it is deleted immediately ...

[MWASoftware]

Are you assigning a unique primary key?

[patyigit]

Yes, Primary key, AutoIncrement.

[MWASoftware]

Does it work if you are using an ordinary TDBGrid?

[patyigit]

I did an experiment: I put a DBGrid, a DBControlGrid and a DBNavigator on the form.
I connected them to the DataSource (and the other accessories).
Working together, they produce the same error, it flashes on Insert and nothing !
When I delete the DataSource property of the DBControlGrid, i.e. "turn it off", the insert works perfectly with the plain DBGrid !

So the conclusion is the following:

1. it works with the plain DBGrid.
2. it doesn't work with the DBControlGrid.
3. Both together on the same DataSource, neither of them works, the DBControlGrid kills the insert of the plain DBGrid too !

[MWASoftware]

Looks like there is a built in assumption somewhere about the way IBX works and zeos doesn't. It would be useful to know if this is a first record insert problem, or if it applies to any record insert.

[patyigit]

As I see, wherever I try to insert a new record, it doesn't work, it doesn't matter if it's the first record or any other. I haven't tried it on an empty table, although there's not much hope, but I might try that too...
And I tried it with the FPC SQLDB package, it doesn't work the same way as with Zeos !

[MWASoftware]

Ok. I'll look at it ans try and see what the problem is.

[patyigit]

I tested it on an empty table, the following happens:

• Empty table (0 records), I press the Insert button of the DBNavigator and nothing happens on the DBControlGrid (the plain DBGrid puts its first row in Edit mode). But then I start typing something in one of the DBEdit fields on the DBControlGrid panel, then it goes into Edit mode and I can (Post the record and I have 1 new record !
• I have a new record, and I want to add another one, but I can't, because of the previously described phenomenon. From here I can only modify the first record, but I can't create a new record.

[MWASoftware]

I believe that this may be to do with the setting of the TDataset.Modified flag after calling insert.

What I suggest you do is to comment out line 739 of DBControlGrid.pas

  if aDataSet.State = dsInsert then
  begin
    FRequiredRecNo := aDataSet.RecNo + 1;
//    Application.QueueAsyncCall(@DoSelectNext,0);
  end;
  UpdateActive
end;           

and try again.
This is not intended to be a complete fix and may not select the newly inserted line. It's to see if we are on the correct path.