Can I use variant property?
lazarus / 31-LCL

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korba812 · 2016-05-15 09:56

Hi!
How can I use and store variant property in LFM?
I tried something like this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
TestComponent; {$mode objfpc}{$H+} interface uses  Classes,
SysUtils; type   { TTestComponent }   TTestComponent =
class(TComponent)  private    { Private declarations }    FVarProp:
Variant;    procedure ReadVarProp(AReader: TReader);    procedure
WriteVarProp(AWriter: TWriter);  protected    { Protected declarations
}    procedure DefineProperties(Filer: TFiler); override;  public    {
Public declarations }  published    { Published declarations }   
property VarProp: Variant read FVarProp write FVarProp; 
end; procedure Register; implementation procedure Register;begin 
RegisterComponents('Test',[TTestComponent]);end; { TTestComponent
} procedure TTestComponent.ReadVarProp(AReader: TReader);begin 
FVarProp := AReader.ReadVariant;end; procedure
TTestComponent.WriteVarProp(AWriter: TWriter);begin 
AWriter.WriteVariant(FVarProp);end; procedure
TTestComponent.DefineProperties(Filer: TFiler);begin  inherited
DefineProperties(Filer);  Filer.DefineProperty('VarProp',
@ReadVarProp, @WriteVarProp, True);end; end.But I can't edit property
in obect inspector and can't store it to LFM because
TLRSObjectReader/TLRSObjectWriter have no implemented functions
WriteVariant/ReadVariant.

So, how can I use variant properties?

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Bart · 2016-05-15 10:11

Don't publish them?

Bart

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korba812 · 2016-05-15 10:27

This is a solution, but unfortunately I need to be able to edit such
properties at design time.

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Thaddy · 2016-05-15 10:48

If variants generate/can generate  rtti with sufficient info
(publishable), you can write your own property editor that handles the
variants (would be a very, very, very complex one) . In DXE7+ this is
possible, don't know about lazarus.

To me it is a bit counter-intuitive to have variants edited at design
time.

Another approach is to handle the variants that you expect as sub-
properties that are mutually exclusive.

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korba812 · 2016-05-15 12:03

It seems that this functionality has not been implemented yet. I found
TVariantPropertyEditor, but it looks unfinished. It seems that it
should not be difficult. I'll try.