TRecall
[Properties (by Name)][Methods (by Name)][Events (by Name)]
Helper class for storing published properties
Declaration
Source position: classesh.inc line 469
Type
TRecall = class (TObject)
private
FStorage : TPersistent;
FReference : TPersistent;
public
constructor Create(AStorage: TPersistent; AReference: TPersistent);
destructor Destroy; Override;
procedure Store;
procedure Forget;
Reference : TPersistent;
end
;
Description
TRecall is a helper class used to copy published properties of a class (the reference object) in another class (the storage object). The reference object and storage object must be assignable to each other.
The TRecall can be used to store the state of a persistent class, and restore it at a later time.
When a TRecall object is created, it gets passed a reference instance and a storage instance. It immediately stores the properties of the reference object in the storage object.
The Store method can be called throughout the lifetime of the reference object to update the stored properties.
When the TRecall instance is destroyed then the properties are copied from the storage object to the reference object. The storage object is freed automatically.
If the properties should not be copied back from the storage to the reference object, the Forget can be called.
Members
| Member | Type | Visibility | Description |
|---|---|---|---|
| Create | Method | public | Creates a new instance of TRecall. |
| Destroy | Method | public | Copies the stored properties to the reference object and destroys the TRecall instance. |
| Forget | Method | public | Clear the reference property. |
| FReference | Field | private | |
| FStorage | Field | private | |
| Reference | Property | public | The reference object. |
| Store | Method | public | Assigns the reference instance to the storage instance. |
Inheritance
| Class | Description |
|---|---|
| TRecall | Helper class for storing published properties |
See also
| Name | Description |
|---|---|
| TPersistent | Base class for streaming system and persistent properties. |
| TPersistent | Base class for streaming system and persistent properties. |
| TPersistent | Base class for streaming system and persistent properties. |
| TPersistent.Assign | Assign the contents of one class to another. |
| TRecall.Create | Creates a new instance of TRecall. |
| TRecall.Destroy | Copies the stored properties to the reference object and destroys the TRecall instance. |
| TRecall.Forget | Clear the reference property. |
| TRecall.Store | Assigns the reference instance to the storage instance. |