Suggestion on TExtendedStringList
lazarus / 7-LCL

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Sieben · 2020-10-14 12:25

Just trying to re-inject this non-performing discussion at a more
suitable place. Due to minor flaws of TExtendedStringList I'd like to
make the following suggestion to the maintainers of LazUtils and
StdCtrls:

- rewrite TExtendedStringList to a new class TRecordStringList that
corrects some minor flaws - for instance a CheckIndex as first line of
CreateRecord so that no memory is allocated for an index that might
not exist - and at the same time introducing a new ancestor class
TCustomRecordStringList that can be used to descend lists that for
example might look like this:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i  
TCheckList = class(TCustomRecordStringList)  private    function
GetCheckMode(Index: Integer): TCheckMode;    function
GetCheckState(Index: Integer): TCheckState;    procedure
SetCheckMode(Index: Integer; AValue: TCheckMode);    procedure
SetCheckState(Index: Integer; AValue: TCheckState);  public   
constructor Create; reintroduce;    property CheckMode[Index:
Integer]: TCheckMode read GetCheckMode write SetCheckMode;    property
CheckState[Index: Integer]: TCheckState read GetCheckState write
SetCheckState;  end; 
without confusing the user with the record properties or methods and
without having to create a TObject descendant for those indexed
properties.

- add RecordStrings to LazUtils and replace TExtendedStringList within
TCustomListBox with TRecordStringList. TRecordStringList just exposes
all properties needed to deal with 'unknown' records like in
TCustomListBox.

- leave ExtendedStrings in LazUtils in case there is code out there
that relies on the current layout of TExtendedStringList, but
eventually mark it as deprecated

I'm including recordstrings.pas and a recordstrings.diff created with
rev 64001 so that these proposed changes can be tested with trunk.

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Sieben · 2020-10-16 14:46

New zip-file with updated recordstrings.diff created with rev64027 due
to changes in LazUtils.lpk and .pas.