Question

I have a class which holds multiple filenames inside a TStringList. I can access a particular filename by index using:

myclass.stringlistclass[index]

But how can I get an filename using the following syntax?

myclass[index]

Is there a property I can implement to achieve this functionality?

Answer 1

private
  function GetColumnValue(const ColumnName: string): string; overload;
  function GetColumnValue(Index: Integer): string; overload;
  procedure SetColumnValue(Index: integer; const Value: string);
public
  property Values[const ColumnName: string]: string read GetColumnValue; default;
  property Values[ColumnIndex: integer]: string read GetColumnValue write SetColumnValue; default;
end;

This means:

• you can have multiple default indexor properties
• the multiple indexor properties can have the same name e.g., Values
• the properties getters can be overloads (i.e. have the same name) e.g., GetColumnValue
• Delphi will resolve the overloads by type signature