Lars Fosdal

Can you offer an example?

I am trying to improve my tendency to spin off a discussion in a thread focused on something else, so here we are. To reiterate, my preference for classes over records with regards to generics, is that read-only generics for records works perfectly for its use, but when you need to update the content in the record, it becomes a very different exercise. You either need to have structure specific methods to change the record field values, or you must copy the entire record, modify it, and the copy it back. The first option wreaks havoc on reuse, and the second option can become a performance bottleneck if the record is large. Even more so, if the record is multidimensional, containing records with arrays of records. The same kind of change in a multidimensional class, is trivial in comparison. @David Heffernan - hence my "the amount of reuse" argument.

Moved my digressions to

"the amount of reuse" was my point.

We also know that the two need to be handled differently when it comes to changing their contents.

I splitted this thread off this

Splitted off the Interposer discussion.

If I did the my own component approach - I would need multiple versions of the design time components to deal with the different methods of feeding data to the controls, and every time I upgraded TMS, or made a change to the wrapper, I would have to rebuild them. Since the wrapper code is continuously evolving - switching between Live, Pilot and Trunk would be very cumbersome if I had to swap the components used as well. Since the data side of the wrapper is not linked to visual code and the events are connected to the wrapper and not the component, it is easy to write non-visual test code that can simulate UI events. Custom components are an option, but. I personally prefer the wrapper approach.

We use interposers or wrapper classes to populate third party components such as the grid, list and combo controls from TMS. It started with us having hundreds of grids, and to get a normalized look, it was better to use a wrapper class to set them up, than to manually configure each class in each form. This class eventually evolved into several wrappers, most of them being data-aware so that we had unified ways of populating a grid, list or combo - straight from SQL, from object lists, or direct fill from "hard code", as well as handling selection events, etc. Another benefit is that if TMS should happen to make changes or add features - we only need to deal with it in the wrappers.

https://larsfosdal.blog/2019/08/06/generic-command-line-parser-for-delphi-10-3-x/ Also, this thread contains numerous other parsers.

Start a new topic. Give some examples.

Another benefit of using generic classes over records is the amount of reuse.

True that.

I agree. If we consider the current example, what would be your choice?

Exactly. Which is why I use objects.

TList<^TDataRec>?

Which is why I don't use dictionaries with records. It is rare that I load up a dictionary and do not need to change some of the content later. If I was insistent on doing records, I would probably write code that ordered the array by the key and did binary lookup to a pointer to the record.

@David Heffernan The last time I tried that, I was changing copies of what I had put into the dictionary. Perhaps I was doing it wrong?

How many elements in Data ?

@Larry Hengen - did you change the access rights (chmod) on the db file as well? What are the access rights?

Have you tested without extra IDE extensions?

Found a somewhat related case to my issue in QP: https://quality.embarcadero.com/browse/RSP-28514 Added my comments to it.

See comments #1 Ctrl+Shift+ArrowUp/Down does not work. Seems to be due to typed constant. See comments #2: Broken class completion, seemingly due to same cause as #1. program SydneyCodeNav; {$APPTYPE CONSOLE} {$R *.res} uses System.SysUtils; type TRec = record a: Integer; // procedure Test; // #2 Uncomment line and press Ctrl+Shift+C to complete code end; TMyObject = class const TR:TRec = (a:1); private procedure InternalTest; // #1 Place cursor here, try Ctrl+Shift+ArrowDown does not work public procedure Test; end; TUnrelated = class // procedure Unrelated; // #2 Uncomment line and press Ctrl+Shift+C to complete code end; { TMyObject } procedure TMyObject.InternalTest; begin Writeln('InternalTest'); // #1 Place cursor here, Ctrl+Shift+ArrowDown end; procedure TMyObject.Test; begin Writeln('Test'); // #1 Place cursor here, Ctrl+Shift+ArrowDown does not work InternalTest; // Ctrl-Clicking InternalTest works end; procedure Test; // Chtrl+Shift+ArrowUp/Down works here var o: TMyObject; begin o := TMyObject.Create; // Chtrl+Shift+ArrowUp/Down works here try o.Test; finally o.Free; end; end; begin try try Test; except on E: Exception do Writeln(E.ClassName, ': ', E.Message); end; finally Write('Press Enter: '); Readln; end; end.

I haven't seen that specific problem, but I have some units where Ctrl+Shift+Arrow up/down simply refuses to work in 10.4.1 as well as 10.3.3. I need to try to make a minimal example and report it.

Is this to navigate between interface and implementation for a class method?