Solved

Problems with TCollection

Posted on 1997-03-18
1
183 Views
Last Modified: 2010-04-04
I'm a new Delphi 2 user and I want rewrite some TPW programs in D2, but I don't know how the TCollection object works in D2.
My code in TPW is
Type
   PData = ^TData
  TData = Array[0..MaxPoint] of Real;
var
  MyCurve : TCollection;
  Data : PData;

begin
   Data:=New(PData);
   MyCurve:=New(PCollection,Init(10,2));
  ....
   MyCurve^.Insert(Data);
  ....
end.

What is the code in Delphi to do the same thing ?
Thank's for your help.

--
Jean-Louis LAVIE
<jean-louis.lavie@esa5017.u-bordeaux2.fr>

0
Comment
Question by:jllavie
1 Comment
 
LVL 3

Accepted Solution

by:
mheacock earned 50 total points
ID: 1334892
[This is from the TCollections section fo the Delphi help file].
------------------------------------------------------------
The TCollection object is used to maintain a collection of TCollectionItem objects. TCollection maintains an index of the collection items in its Items array. The Count property contains the number of items in the collection. Use the Add and Clear properties to add new items to the collection or to delete items from the collection. Objects descended from TCollection can contain objects descended from TCollectionItem. Examples are in the TStatusBar and THeaderControl controls which use TStatusPanels and THeaderSections collection objects to contain TStatusPanel and THeaderSection collection items.

In addition to these properties, methods, and events, the TCollection object also has the methods that apply to all objects and is a direct descendent of TPersistent.
--------------------------------------------------------------

Just by looking at your code, it looks to me that a TList might better serve your purposes.  A TList keeps a list of pointers.  Since you want to store Reals (btw, the Real type is slowly being phased out and is incompatible with other programming languages, use Single, which is byte compatible with C/C++'s Float), the Tlist would store pointers to those real objects.

If you replace TList with TCollection in your code, the changes are very simple.

var
    MyCurve: TList;
    ...
begin
    ...
    MyCurve := TList.Create;
    ...
    MyCurve.Add(Data);
    ...
    Data := TData(MyCurve.Items[n]);
end;
0

Featured Post

Master Your Team's Linux and Cloud Stack

Come see why top tech companies like Mailchimp and Media Temple use Linux Academy to build their employee training programs.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

This article explains how to create forms/units independent of other forms/units object names in a delphi project. Have you ever created a form for user input in a Delphi project and then had the need to have that same form in a other Delphi proj…
Have you ever had your Delphi form/application just hanging while waiting for data to load? This is the article to read if you want to learn some things about adding threads for data loading in the background. First, I'll setup a general applica…
Two types of users will appreciate AOMEI Backupper Pro: 1 - Those with PCIe drives (and haven't found cloning software that works on them). 2 - Those who want a fast clone of their boot drive (no re-boots needed) and it can clone your drive wh…
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…

810 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question