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Questions tagged [tpersistent]

TPersistent is the ancestor for all objects that have assignment and streaming capabilities. It is defined in the Classes.pas unit.

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Runtime design - storing and loading form layout (recursively?)

I'm creating an application which layout needs to be fully configurable on client-side. It means each component (control) can be resized and moved around the form, new controls can be added, or some removed. I'd like to use JVCL Runtime Design…
migajek
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Ignore unknown properties when reading object from stream

We have an application that stores project information in a file by descending from TPersistent. We use TSteam.ReadComponentRes to read from a stream to the object. We would like to be able to open project files with unknown properties (from newer…
boileau
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Writing C++ Builder/Delphi component and save a binary property to DFM files

I wrote a C++ builder component to display SVG files perform some stuff on them. For now, I published a property named SvgFile (UnicodeString) which can be initialized in the IDE with the file name of the SVG file. This works fine. This property is…
A.G.
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Save/Load TObject(TPersistent) to XML

everybody. I'm trying to save my class: TA= class(TPersistent) private FItems: TObjectList; FOnChanged: TNotifyEvent; public constructor Create; destructor Destroy; override; ... procedure Delete(Index: Integer); …
Keeper
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Can I serialize a Delphi TPersistent as a field of TComponent using the default WriteComponent action?

I'm getting very confused about how to write out properties from a TComponent that has a TPersistent field. For example I have: TChildObj = class( TPersistent ) PRIVATE FVisible: boolean; FColor: TColor; PUBLIC PUBLISHED property…
Brian Frost
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Collection editor does not open for a TCollection property in a TPersistent property

I've got my custom collection property which is working great when it is a direct member of my component. But I want to move the collection property to a TPersistent propery within my component. And now comes the problem, it doesn't work: double…
JustMe
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Best way to implement Clone() in my specific classes

In my specific TPersistent classes I'd like to provide a Clone function, which returns an independent copy of the object. Is it possible to make this work correctly with descendants, without implementing the Clone function in each and every…
maf-soft
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TPersistent + interface, Delphi

I need a class that is based on TPersistent (so it stores the RTTI) and includes default Interfaces handling (QueryInterface, _AddRef, _Release) ... what is the class name I'm looking for?
migajek
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Collection Indexing Strategy

I have a collection of TPersistent objects. I want to index them by their memory location (as main index) and by their properties (using rtti). A collection may have several property based indexes (based on different properties). What is the…
Luthfi
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Delphi Streaming Problem

I'm using a blob field in a kbmMemTable to store a custom component that I've developed from TComponent and I use the read and write component stream methods of the TReader to read and write the component to the blob field. The data in the…
golfur
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Delphi - Custom thread not being created

i'm having a bit of a problem here. I have a custom class that inherits TPersistent class, inside(private section) this custom class, i have a custom made TThread with overriden Execute method which fires every (1000 ms). Everything works great,…
Ironcross
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Persisting more than one object in Delphi 7

This is not a duplicate but a follow-up to "Persistent Objects in Windows XP/Delphi 7." I need to persist more than one object in Delphi 7, and the objects are a class family. RRUZ's answer suggests I inherit from TPersistent and use…
DelphiProgrammer
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TColumn.FieldName property editor

I'm analyzing the DBGrids.pas unit. There's a TColumn class which have published the FieldName property property FieldName: String read FFieldName write SetFieldName; It's declared as a string but in the object inspector it's appear as a editable…
JustMe
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TPersistent component in a TCollectionItem / Access a TCollectionItem property from a TPersistent

Please take a look to the bellow code part of a TComponent: TMyField = class(TCollectionItem) private FName: String FSqlField: TSqlField; procedure SetName(const Value: String); procedure SetSqlField(const Value: TSqlField) published …
REALSOFO
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How can a Delphi TForm / TPersistent object calculate its own construction and deserialization time?

For performance tests I need a way to measure the time needed for a form to load its definition from the DFM. All existing forms inherit a custom form class. To capture the current time, this base class needs overriden methods as "extension…
mjn
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