[Lazarus] TBufDataset issues

[Werner Pamler]

Am 30.04.2020 um 10:45 schrieb Michael Van Canneyt via lazarus:
> I added several menus:
> - Create dataset (what you need)
> - Save data to file (allows to save data in memory to file)
> - Load data from file (allows to load data from a file into memory) - 
> Copy data from another dataset (what it says on the tin :-))
Thank you.

>>> (2) Persistent fields: Wanting to create persistent fields at design 
>>> time I do this: Make sure that the BufDataset is active. Right-click 
>>> on the component to add the Fields Editor. I see the fields created. 
>>> But how do I make them persistent? In Delphi I select both fields 
>>> and click the '+'. Here the field list which opens is empty and the 
>>> "Create" button is disabled. In other datasets everything is working 
>>> correctly here, but TBufDataset seems to be incomplete.
> Works fine here, be sure to set correct properties for the fields you 
> add.
> If any of the fields has incorrectly configured properties, it won't 
> work.
>
> But I did this when the dataset was not yet active. Maybe that is your
> problem.

Although I had it working some time after I had sent my mail I now have 
the same issue again and I don't know why- see attached demo. I had 
entered two field defs, clicked the new "CreateDataset" option (which 
automatically set the Dataset to Active, however, not immediately, only 
after clicking somewhere else). I saved the project in this state. When 
you load it into Lazarus you must first create the dataset again, 
because i did not specify a filename since it must be absolute and won't 
fit to your directory structure. The FieldsEditor and trying to add 
persistent fields always leads me to the state with the empty field list 
and disabled "Create" button.

I should note also that when I experimented with FileName specified the 
IDE was in a pretty unstable state and crashed easily. I cannot 
reproduce, however, what I did exactly. But it happened rather 
frequently, at some stage the IDE crashed when I tried to click off the 
Active property, but this was gone after I reloaded the project.


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