Delphi multi-TList data file

Posted by eeleong on April 12, 2001 at 14:08:44:

I have create an data-structure using TList, but have problem save it into file.

....
Data Structure is something like this,

A:TList;
B:TList
C:TList
D:TResullt

TResult=class(TPersistent)
begin
Property FValue;
Property FResult;

end;

.......

I add several different TResult object into C , and several different C into B and several B into A.
Everything work quite well

But I have problem with saving All information in A into a file.

I have tried the following way:
1. Save as Typed file- failed as Object cannot save as typed file (violated polymorishim rule),
Then I tried to change the TResult into a Record instead of Class, but the same problem still arrive when I want to save B.

2.Save as UnTyped binary File –In order to create untyped file , the information have to read from a buffer, but i dont know how to send A to a buffer.
I try to treat A as buffer but failed. ( regarding the binary file , how should i know how much memory to allocate to it , if the file will be getting larger and larger.)

3. Use TStream, having problem with send A into buffer.

4. Use TFiler/TWriter/TReader ...... I manage to do save it when i have a list of TResult,i.e. several TResult object into C , and save the C but I dont know how to extend it further.
TFiler only do standard data type( int,string ,componet) file IO, but i really dont know how to ask them to write or read TList.
I saw a abstract method know as Write/Read ,but I really dont know how to make it to suitable my data-type.
I think there is a way to use TFiler and recursive algorithm to do the File IO, but i am not too sure how to do it , I hope it is not too complicated.

I welcome any suggestion , even on DataStructure.

finally I am using Delphi 2.