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Hide a property

Posted on 2004-10-07
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Last Modified: 2010-05-18
How can I hide one of my property ? I moved to public area, but in this case don't save my settings. Just when I let it into published my vcl save parameters to dfm file.

What to do to have it hidden but to store my parameters ?
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Question by:ginsonic
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7 Comments
 
LVL 7

Expert Comment

by:LRHGuy
ID: 12251778
In your component, add:

private
   fYourPropertyBool:boolean;
protected
    procedure DefineProperties(Filer:TFiler);
      override;


Then make:

procedure Comp.DefineProperties(Filer:TFiler);
begin
  inherited DefineProperties(Filer); { allow base classes to define properties }
  Filer.DefineProperty('YourPropertyName'',True,LoadProperty_YourPropertyBoll,StoreProperty_YourPropertyBool,True);
end;

procedure Comp.LoadProperty_YourPropertyBool(Reader:TReader);
begin
  fYourPropertyBool:=Reader.ReadBoolean;
end;

procedure Comp.StoreProperty_YourPropertyBool(Writer:TWriter);
begin
  Writer.WriteBoolean(fYourPropertyBool);
end;


fYourPropertyBool just happens to be a boolean property. Make whatever you need!

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Expert Comment

by:joncmora
ID: 12255496
I don't see the reason why you want to do this.

How can that property be assigned a value at design time when it's not published? IMO, the purpose of the DFM file is to store (non-default) values set at design time. Other than that, you have to assign your values in code.
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LVL 7

Expert Comment

by:LRHGuy
ID: 12255512
I sometimes do this to store a state variable related to but not directly addressable by a user definable property. For example, if it's using an internally generated bitmap, or one the user supplied.
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Expert Comment

by:joncmora
ID: 12255529
I see. Now I think I know what ginsonic is trying to achieve.
0
 
LVL 9

Author Comment

by:ginsonic
ID: 12256011
My property is a TCollection not a boolean. What to do ?

I wish to hide it because I use my own editor when double click on vcl.
0
 
LVL 7

Accepted Solution

by:
LRHGuy earned 500 total points
ID: 12263672
It's the same setup, you'll just have to save the collection, item by item, in the save routine (and the load routine)

procedure Comp.LoadProperty_YourProperty(Reader:TReader);
begin
// load your collection here
  Reader.ReadCollection(MyCollection);
end;

procedure Comp.StoreProperty_YourProperty(Writer:TWriter);
begin
// save your collection here
  Writer.WriteCollection(MyCollection);
end;

The ReadCollection and WriteCollection will call Read/WriteProperties() for each item in the list.

Note that you'll have to have each of the individual fields of the collection items defined as property in the DefineProperties method.
0
 
LVL 9

Author Comment

by:ginsonic
ID: 12265268
LRHGuy, I use same code untill now. For defineProperties I use:

procedure TmyVcl.DefineProperties(Filer: TFiler);
begin
  inherited DefineProperties(Filer);
  Filer.DefineProperty('MyCollection', LoadProperty, StoreProperty, FMyCollection.Count > 0);
end;

Can you tell me more, maybe codes, for defining the fields of  my  collection?
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