type TObject = class
constructor Create;
...
...
destructor Destroy; virtual;
end;
Description
The TObject type defines the base class type. It is the oldest grandparent of all classes - every class is ultimately derived from TObject.
Because of this, every object inherits the methods of TObject.
The TObject methods fall into two categories - class and non-class. When prefixed by the keyword Class, a method may be called in both an object of the class, and in the class itself. Such a static method cannot access any class fields because a class has no data itself - only instantiated classes - objects - have data.
Some key Class (static) methods:
function ClassName Gives the class name as a string
ClassParent Gives the class parent name
ClassInfo Gives class Run Time info
InstanceSize Size of class object in bytes
NewInstance Creates a new class object
Some key Object methods:
Create Empty object creator
Free Calls Destroy for a non-nil object ref
Destroy Releases object storage
AfterConstruction Called after construction
BeforeDestruction Called before destruction
Related commands
Class Starts the declaration of a type of object class
Printer Returns a reference to the global Printer object
Example code : Using TObject methods inherited in a TForm subclass
begin
// The unit form was derived from TObject.
// So we can use methods of TObject:
ShowMessage('Form1 object class name = '+
Form1.ClassName);
ShowMessage('Form1 object class parent name = '+
Form1.ClassParent.ClassName);
ShowMessage('Form1 object instance size = '+
IntToStr(Form1.InstanceSize));
// And now on TObject itself
ShowMessage('TObject class name = '+
TObject.ClassName);
ShowMessage('TObject instance size = '+
IntToStr(TObject.InstanceSize));
end;
Show full unit code
Form1 object class name = TForm1
Form1 object parent class name = TForm
Form1 object instance size = 764
TObject class name = TObject
TObject instance size = 4