Possible to "extend" or "inherit" an existing class/record helper?

[wuwuxin 28]

For System.SysUtils.TStringHelper,  I have to need to add some additional methods -  is it possible to extend or "inherit" an existing class/record helper to add user-specified methods?

[David Heffernan 2345]

17 minutes ago, wuwuxin said:

is it possible to extend or "inherit" an existing class/record helper to add user-specified methods?

No. Longstanding limitation. Kinda sucks. Can't have multiple helpers which would be another way to do what you want. 

Edited November 19, 2021 by David Heffernan

[Uwe Raabe 2057]

While the above is valid for record helpers, it is indeed possible to extend class helpers. (It es even documented: https://docwiki.embarcadero.com/RADStudio/Alexandria/en/Class_and_Record_Helpers_(Delphi)#Helper_Syntax)

 

In this example we extend the existing class helper TRESTRequestParameterHelper from REST.Client.pas (Delphi 11) with another method without hiding the ContentType member of TRESTRequestParameterHelper.

 

type
  TMyRESTRequestParameterHelper = class helper (TRESTRequestParameterHelper)  for TRESTRequestParameter
    procedure MyTest;
  end;