[SOLVED] I cannot compile my LPK in Lazarus 1.6 when using an empty property

[CM630]

I have updated Lazarus to 1.6 recently and it occurs that I cannot compile one of my LPKs.
In the pas file I have:

Code: Pascal  [Select][+][-]

1.  TArrowStar = class(TCustomControl)
2.  
3. ...
4. published
5. ...
6. property RepetitiveMode :Boolean read FRepetitiveMode write FRepetitiveMode;    //Enable/disable repetitive mode
7.     property RepeatsUntilFastRate :Cardinal read FRepeatsUntilFastRate write FRepeatsUntilFastRate;  //How many times the control shall be actuated, in repetitive mode, until it switches to fast rate
8.     property Height: Integer; //Prevent Height form being shown in the Properties panel of the Object Browser
9.     property Width:  Integer; //Prevent Width form being shown in the Properties panel of the Object Browser
10. ...
11.  

   
I get the following message arrowstar.pas(113,29) Fatal: Syntax error, "READ" expected but ";" found on property Height: Integer;
I did not have this problem with previous version of Lazarus 

[Thaddy]

That is a visibility re-declaration. Did you check the base class? That might have changed.

[CM630]

If I undestartand you right by „Did you check the base class? That might have changed.‟ you meant „Did you check if the Height and Width property still exist in the TCustomControl class‟.Yes, they do. Could this error be due to a bug in Lazarus/FPC?

[Thaddy]

Well, can you provide a simple compilable/crashable/refusing to compile  example?
Because it looks like a bug, but in that case the whole LCL should fall apart and that is not the case.

A possible explanation is that there are some dirty files. So clean up and rebuild.

[CM630]

Well, can you provide a simple compilable/crashable/refusing to compile  example?

The source is here, I checked that it does not need some special dependencies, so I guess there is no reason to make it shorter?

[wp]

In a property redeclaration you only specify the property name, not the property type.

But your comment shows that you want to hide the "Height" and "Width" properties in the object inspector. Did you try "RegisterPropertyToSkip()" (in LResources)?

[CM630]

I changed

Code: Pascal  [Select][+][-]

1.    property Height: Integer; //Prevent Height form being shown in the Properties panel of the Object Browser
2.    property Width:  Integer; //Prevent Width form being shown in the Properties panel of the Object Browser
3.  

to
I changed

Code: Pascal  [Select][+][-]

1.  property Height; //: Integer; //Prevent Height form being shown in the Properties panel of the Object Browser
2.  property Width; //:  Integer; //Prevent Width form being shown in the Properties panel of the Object Browser
3.  

Now it compiles, but Height and Width are shown in the Object Inspector.
I will check where exactly shall I put RegisterPropertyToSkip and report back.

[balazsszekely]

@CM630
Now it compiles, but Height and Width are shown in the Object Inspector.

Just move Width and Height from published to public section and you're good to go:

Code: Pascal  [Select][+][-]

1. type
2.   TArrowStar = class(TCustomControl)
3.   private
4.     FRepetitiveMode :Boolean;
5.     FRepeatsUntilFastRate :Cardinal;
6.   public
7.     property Height;
8.     property Width;
9.   published
10.     property RepetitiveMode :Boolean read FRepetitiveMode write FRepetitiveMode;
11.     property RepeatsUntilFastRate :Cardinal read FRepeatsUntilFastRate write FRepeatsUntilFastRate;
12.   end;

[CM630]

But your comment shows that you want to hide the "Height" and "Width" properties in the object inspector. Did you try "RegisterPropertyToSkip()" (in LResources)?

I tried. I added
   

Code: Pascal  [Select][+][-]

1. RegisterPropertyToSkip(TArrowStar, 'Height','', '');
2.     RegisterPropertyToSkip(TArrowStar, 'Width','', '');

 
in

Code: Pascal  [Select][+][-]

1. constructor TArrowStar.Create (aOwner: TComponent);
2.   function CreateArrow(ArrowType:TArrowType):TArrow;
3.   begin

           


also in

Code: Pascal  [Select][+][-]

1. procedure Register;
2. begin
3.   {.$I arrowstar_icon.lrs}
4. RegisterPropertyToSkip(TArrowStar, 'Height','', '');
5.     RegisterPropertyToSkip(TArrowStar, 'Width','', '');

   


and also in

Code: Pascal  [Select][+][-]

1. initialization
2.        RegisterPropertyToSkip(TArrowStar, 'Height','', '');
3.     RegisterPropertyToSkip(TArrowStar, 'Width','', '');
4.  

All in vane!


 

  public
    property Height;
    property Width;

That not working neither

     

[balazsszekely]

That not working neither

Try again, because it works!

[wp]

That not working neither

Try again, because it works!

It's not working with me either. I always thought that it is not possible to decrease the visibility level of a property, but the RegisterPropertyToSkip which I saw in some TAChart code confuses me. Maybe it refers to property identifiers which may be in the lfm file but which actually are not available in the class. Importing dfm files from Delphi may present such a situation.

The Width and Height properties were published in the first place when they were introduced in TControl. Probably because Delphi does it the same way. In my eyes, a severe design fault because descendent classes never can hide these properties (and some more) in the Object Inspector.

@CM630: What is the problem to have these properties in the Object Inspector?

[Mike.Cornflake]

I always thought GetMem's solution would work as well.

This may help.
See Mattias Gaertner's reply
http://comments.gmane.org/gmane.comp.ide.lazarus.general/84290

On Wed, 11 Nov 2015 18:45:52 +0100
Gabor Boros <gaborboros <at> yahoo.com> wrote:

> Hi All,
>
> I use a property grid in my application and don't want to advertise my
> class names to the users. For example (TSizeConstraints) displayed next
> to Contraints. Any idea how to hide class names or override at
> object(TPersistent) level?

You cannot decrease visibility in Free Pascal.
You can hide properties in the Object inspector. For example

  RegisterPropertyEditor(TypeInfo(TAnchorSide), TControl, 'AnchorSideLeft', THiddenPropertyEditor);

Mattias

[wp]

Ah, thanks, Mike  - this works.

@CM630: Add these lines to the Register procedure:

Code: Pascal  [Select][+][-]

1.   RegisterPropertyEditor(TypeInfo(integer), TArrowStar, 'Width', THiddenPropertyEditor);
2.   RegisterPropertyEditor(TypeInfo(integer), TArrowStar, 'Height', THiddenPropertyEditor);

This requires propedits in the uses clause of the unit and package ideintf in the package requirements.

But note that these properties still can be accessed at runtime.

[balazsszekely]

@wp, @Mike.Cornflake
https://youtu.be/iLhPKiJf1ww

[wp]

"Width" and "Height" are "published" from the very first ancestor ever. Making it "public" means to decrease its visibility from "published" to "public" which is not possible.

The property "Visible" of your property, however, always has been "public". Your video decreases the visibility of this property of TButton to "public", but the ancestor of TButton, TCustomButton, had it as a "public" property already. Therefore your video works because you don't reduce visibility at all. Try to make the property "protected" - I guess this will not work...