Object type property

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2 total messages Started by Marc Scheuner Thu, 26 Feb 1998 00:00

#39

Author: Marc Scheuner
Date: Thu, 26 Feb 1998 00:00

39 lines
2012 bytes

Folks

I need to have a property in one of my components that will be visible
in the object inspector, and that works like the "Font" property in
that it will fold open and display a number of related properties.

What I'm trying to do is to bundle together a number of field names in
a table that I need to reference. I declared a type 

TFieldNames = class  (* MSE *)
    Prop : String;
    Form : String;
    ValueD : String;
    ValueF : String;
    ValueI : String;
end;

and used it in my component as a property:

    property FieldNames : TFieldNames read FFieldNames
                                           write FFieldNames;

In the constructor of my component, I create the internal FFieldNames
variable. I see this property in the object inspector, but I can't get
it to fold open nicely, I always get nothing but a General Protection
Fault.

What am I missing? Do I need a property editor, just for a few
strings? Am I missing something else? Can someone provide a sample of
a component with such a property that's working properly??

Thanks in advance!
Marc


======================================================================
[ Marc Scheuner, marc.scheuner@berner.ch  CH-3001 BERNE, Switzerland ]
======================================================================

Re: Object type property

#40

Author: Robert Cerny
Date: Fri, 27 Feb 1998 00:00

64 lines
2636 bytes

Marc Scheuner <marc.scheuner@NO.SPAM.PLEASE.ch> wrote in article
<34f53726.9264792@news.bernoise.ch>...
> Folks
> 
> I need to have a property in one of my components that will be visible
> in the object inspector, and that works like the "Font" property in
> that it will fold open and display a number of related properties.
> 
> What I'm trying to do is to bundle together a number of field names in
> a table that I need to reference. I declared a type 
> 
> TFieldNames = class  (* MSE *)
>     Prop : String;
>     Form : String;
>     ValueD : String;
>     ValueF : String;
>     ValueI : String;
> end;
> 
> and used it in my component as a property:
> 
>     property FieldNames : TFieldNames read FFieldNames
>                                            write FFieldNames;
> 
> In the constructor of my component, I create the internal FFieldNames
> variable. I see this property in the object inspector, but I can't get
> it to fold open nicely, I always get nothing but a General Protection
> Fault.
> 
> What am I missing? Do I need a property editor, just for a few
> strings? Am I missing something else? Can someone provide a sample of
> a component with such a property that's working properly??
> 

1. TFieldNames MUST descend from TPersistent and must implement Assign
method
2. Values to see in object inspector must be declared as published
properties.
3. The component that uses this object must have write access method
instead of field

TFieldNames = class  (TPersistent)   {1.}
     fProp : String;
  procedure Assign(Source:TPersistent); override;        {1.}
published 
  property Prop:string read fProp write fProp; {!!!!2.}
....


    property FieldNames : TFieldNames read FFieldNames write SetFieldNames;
{!!3.}
.....
procedure xx.SetFieldNames(AFieldNames : TFieldNames);  
begin
  FFieldNames.Assign(AFieldNames)
end;
-- 
-------------------------
Regards,
Robert

Remove leading aa when replying.
MailTo: aarobert.cerny@eunet.si

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