I'm using Delphi 2006 and I have a class defination like this:

TPerson = class
fPersonName  : String;
fPersonSurName : String;
fPersonAge : Integer;
published
 property PersonName : String read fPersonName write fPersonName;
 property PersonSurname : String read fPersonSurname write fPersonSurname;
 property PersonAge  : Integer read fPersonAge write fPersonAge;
end;

and i want to display my class instance using PropertyGrid,so...

var
 mPerson : TPerson;
begin
 mPerson := TPerson.Create;
 mPerson.PersonName := 'Tugrul';
 mPerson.PersonSurname := 'HELVACI';
 mPerson.PersonAge := 31;
 PropertyGrid1.SelectedObject := mPerson;
end;

at the above code i can see my class instance in the property grid.
But i want to change property display names in the propertygrid component.
Because of these, i was searching on the net and i found PropertyDescriptor
abstract class
and ICustomTypeConverter interface.

i implemented theese classes following:

 TArrayOfAttribute = array of Attribute;
 TMyDescriptor = class(PropertyDescriptor)
 private
   base : PropertyDescriptor;
   fName: String;

   function GetName : String;
   function GetDisplayName : String;
   function GetIsReadOnly : Boolean;
   function GetComponentType : &Type;
   function GetPropertyType : &Type;

   function GetCustomNames(baseName : String) : String; // my custom names
getter function
 public
   constructor Create(baseP : PropertyDescriptor; filter :
TArrayOfAttribute); overload; virtual;
   constructor Create(baseP : PropertyDescriptor); overload; virtual;

   function CanResetValue(comp : TObject) : Boolean;
   function GetValue(comp : TObject) : TObject;

   procedure ResetValue(comp : TObject);
   procedure SetValue(comp : TObject; Value : TObject);
   function ShouldSerializeValue(comp : TObject) : Boolean;

   property Name : String read GetName;
   property DisplayName : String read GetDisplayName;
   property IsReadOnly  : Boolean read GetIsReadOnly;
   property ComponentType : &Type read GetComponentType;
   property PropertyType : &Type read GetPropertyType;
 end;

 TMyClass = class(TInterfacedObject, ICustomTypeDescriptor)
 public
   function GetProperties(filter : TArrayOfAttribute) :
PropertyDescriptorCollection; overload;
   function GetAttributes : AttributeCollection;
   function GetClassName : String;
   function GetComponentName : String;
   function GetConverter : TypeConverter;
   function GetDefaultEvent : EventDescriptor;

   function GetEvents(attributes : TArrayOfAttribute) :
EventDescriptorCollection; overload;
   function GetEvents : EventDescriptorCollection; overload;
   function GetDefaultProperty : PropertyDescriptor;

   function GetProperties : PropertyDescriptorCollection; overload;
   function GetEditor(editorBaseType : System.Type) : TObject;
   function GetPropertyOwner(pd : PropertyDescriptor) : TObject;
 end;

and my new TPerson class is:
 TPerson = class(TMyClass)
  fPersonName  : String;
  fPersonSurName : String;
  fPersonAge : Integer;
 published
  property PersonName : String read fPersonName write fPersonName;
  property PersonSurname : String read fPersonSurname write fPersonSurname;
  property PersonAge  : Integer read fPersonAge write fPersonAge;
 end;

**************** IMPLEMENTATIONS BELOW *********************************
{ TMyDescriptor }

function TMyDescriptor.CanResetValue(comp: TObject): Boolean;
begin
  Result := base.CanResetValue(comp);
end;

constructor TMyDescriptor.Create(baseP: PropertyDescriptor;
 filter: TArrayOfAttribute);
begin
 inherited Create(baseP, filter);
 Self.base := baseP;
end;

constructor TMyDescriptor.Create(baseP: PropertyDescriptor);
begin
 inherited Create(baseP);
 Self.base := baseP;
end;

function TMyDescriptor.GetComponentType: &Type;
begin
 Result := base.ComponentType;
end;

function TMyDescriptor.GetDisplayName: String;
begin
 Result := GetCustomNames(base.Name);
end;

function TMyDescriptor.Getir(baseName : String): String;
begin
 if baseName = 'PersonName' then Result := 'Names of the Personel';
 if baseName = 'PersonSurname' then Result := 'Surname of the personel';
 if baseName = 'PersonAge' then Result := 'Age of the personel';
end;

function TMyDescriptor.GetIsReadOnly: Boolean;
begin
 Result := base.IsReadOnly;
end;

function TMyDescriptor.GetName: String;
begin
 Result := base.Name;
end;

function TMyDescriptor.GetPropertyType: &Type;
begin
 Result := base.PropertyType;
end;

function TMyDescriptor.GetValue(comp: TObject): TObject;
begin
 Result := base.GetValue(comp);
end;

procedure TMyDescriptor.ResetValue(comp: TObject);
begin
 base.ResetValue(comp);
end;

procedure TMyDescriptor.SetValue(comp, Value: TObject);
begin
 base.SetValue(comp, value);
end;

function TMyDescriptor.ShouldSerializeValue(comp: TObject): Boolean;
begin
 Result := base.ShouldSerializeValue(comp);
end;

{ TMyClass }

function TMyClass.GetProperties(
 filter: TArrayOfAttribute): PropertyDescriptorCollection;
var
 baseProps : PropertyDescriptorCollection;
 newProps  : array of PropertyDescriptor;
 iCounter  : Integer;
 oldname,
 newname   : String;
begin
 baseProps := TypeDescriptor.GetProperties(GetType(), filter);

 SetLength(newProps, baseProps.Count);

 for iCounter := 0 to baseProps.Count do
 begin
   newProps[iCounter] := TMyDescriptor.Create(baseProps[iCounter], filter);
// An error occured : E2402 constructing instance of abstract class..
   oldname := PropertyDescriptor(baseProps[iCounter]).DisplayName;
   newName := TMyDescriptor(newProps[iCounter]).DisplayName;
 end;

 Result := PropertyDescriptorCollection.Create(newProps);
end;

function TMyClass.GetAttributes: AttributeCollection;
begin
 Result := TypeDescriptor.GetAttributes(Self, true);
end;

function TMyClass.GetClassName: String;
begin
 Result := TypeDescriptor.GetClassName(Self, true);
end;

function TMyClass.GetComponentName: String;
begin
 Result := TypeDescriptor.GetComponentName(Self, true);
end;

function TMyClass.GetConverter: TypeConverter;
begin
 Result := TypeDescriptor.GetConverter(Self, true);
end;

function TMyClass.GetDefaultEvent: EventDescriptor;
begin
 Result := TypeDescriptor.GetDefaultEvent(Self, true);
end;

function TMyClass.GetDefaultProperty: PropertyDescriptor;
begin
 Result := TypeDescriptor.GetDefaultProperty(Self, true);
end;

function TMyClass.GetEditor(editorBaseType: System.Type): TObject;
begin
 Result := TypeDescriptor.GetEditor(Self, editorBaseType, true);
end;

function TMyClass.GetEvents: EventDescriptorCollection;
begin
 Result := TypeDescriptor.GetEvents(Self, true);
end;

function TMyClass.GetEvents(
 attributes: TArrayOfAttribute): EventDescriptorCollection;
begin
 Result := TypeDescriptor.GetEvents(Self, attributes, true);
end;

function TMyClass.GetProperties: PropertyDescriptorCollection;
begin
 Result := TypeDescriptor.GetProperties(Self, true);
end;

function TMyClass.GetPropertyOwner(pd: PropertyDescriptor): TObject;
begin
 Result := Self;
end;

I dont understand what is this. Can anybody helps me , how can i
subclassing PropertyDescriptor class correctly ??

Even we take an error when using  delphi.net , we dont take any error
message using c#,

i want change the display name of the property which is the added to my
special class by using the propertyGrid Component ...
It's seems like DisplayNameAttirubute of the .net Framework 2.0

With My Best Regards,

Thanks For Helping