Streaming a dynamic list of component references

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3 total messages Started by dnote Thu, 17 Dec 1998 00:00

#23

Author: dnote
Date: Thu, 17 Dec 1998 00:00

33 lines
1977 bytes

To all Delphi guru's

I want my component to store a list of component references (on the same or
linked form). To do this the component contains a custom made list class in
which you can add,  delete and query the component references. This list
class is derived from TComponent. A pretty silly example of such a component
could be: a TEdit control which stores the references to multiple TFields in
order to react to their events.

Example code:

TMyEdit = class(TCustomEdit) private  mFields: TFieldList;  ... published  {
references are edited through a property editor, the property write specifier
is  used to allow delphi-form-streaming to take place. }  property Fields:
TFieldList read mFields write SetFields; end;

TFieldList = class(TComponent)
private
  mItems: TList; { of TField }
  ...
public
  procedure Add(aField: TField);
  ...
  property Items[aIndex: integer]: TField read GetItems;
end;

Any suggestions on how to do this (an example DefineProperty, Read and Write
sheme would be great)?

Dave de Jong - Dnote Software

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Re: Streaming a dynamic list of component references

#24

Author: Krzysztof Borys (Bask)
Date: Fri, 18 Dec 1998 00:00

37 lines
2150 bytes

On Thu, 17 Dec 1998 13:13:38 GMT, dnote@my-dejanews.com wrote:

>To all Delphi guru's
>
>I want my component to store a list of component references (on the same or
>linked form). To do this the component contains a custom made list class in
>which you can add,  delete and query the component references. This list
>class is derived from TComponent. A pretty silly example of such a component
>could be: a TEdit control which stores the references to multiple TFields in
>order to react to their events.
>
>Example code:
>
>TMyEdit = class(TCustomEdit) private  mFields: TFieldList;  ... published  {
>references are edited through a property editor, the property write specifier
>is  used to allow delphi-form-streaming to take place. }  property Fields:
>TFieldList read mFields write SetFields; end;
>
>TFieldList = class(TComponent)
>private
>  mItems: TList; { of TField }
>  ...
>public
>  procedure Add(aField: TField);
>  ...
>  property Items[aIndex: integer]: TField read GetItems;
>end;
>
>Any suggestions on how to do this (an example DefineProperty, Read and Write
>sheme would be great)?

Try looking into TCollection from Classes unit or TStrings - it can bring some
ideas. Another way is to use TCollection - you must create class which derives
from TCollectionItem and has a property with TComponent type IMHO this could be
better.
UIN:3620584                                            Bask
mailto:bask@kis.p.lodz.pl

Re: Streaming a dynamic list of component references

#25

Author: dnote
Date: Fri, 18 Dec 1998 00:00

16 lines
1545 bytes

> Try looking into TCollection from Classes unit or TStrings - it can bring some
> ideas. Another way is to use TCollection - you must create class which derives
> from TCollectionItem and has a property with TComponent type IMHO this could be
> better.

The problem is that TCollection and TStrings do not store component
references. I need some mechanism in Delphi with which I can resolve
component name into component objects. It is not an option to uses
TCollection itself, since I need to store references to TComponents like
TFields.

Dave

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