component property stack overflow 1

[rkamarowski]

whenever i attempt to access the GlobalName property in my component i'm getting a stack overflow error. any help would be appreciated.

thanks

======================
unit KMPDGlobalLister;

interface

uses
SysUtils, Classes, Controls, ExtCtrls,
Dialogs, StdCtrls, Trpcb, ToolWin, MFunStr;

type
TNotifyEvent = procedure (Sender: TObject) of object;
TKMPDGlobalLister = class(TPanel)
private
{ Private declarations }
function GetGlobalName: string;
function GetLastNodeAccessed: string;
procedure buttonMoreClick(strVal: String);
procedure SetGlobalName(strVal: string);
procedure SetLastNodeAccessed(strVal: string);
property GlobalName: string read GetGlobalName write SetGlobalName;

protected
{ Protected declarations }
procedure buttonFindClick(Sender: TObject);

public
{ Public declarations }
panelTools: TPanel;
memoGlobalLister: TMemo;
buttonFind: TButton;
buttonMore: TButton;
editGlobalName: TEdit;
labelGlobalName: TLabel;
// properites
property LastNodeAccessed: string read GetLastNodeAccessed write SetLastNodeAccessed;
// methods
Constructor Create(AnOwner:TComponent); Override;
Destructor Destroy; Override;

published
{ Published declarations }
FRpcBroker: TRPCBroker;
property RpcBroker: TRPCBroker read FRpcBroker write FRpcBroker;

end;

procedure Register;

implementation

Constructor TKMPDGlobalLister.Create(AnOwner:TComponent);
begin
inherited Create(AnOwner);
Align:=alClient;
Anchors:=[akLeft,AkRight,akTop,akBottom];
Height:=200;
Width:=200;

panelTools:=TPanel.Create(Self);
with panelTools do
begin
Align:=alTop;
Anchors:=[akLeft,akRight,akTop];
BevelEdges:=[beBottom];
Caption:='';
Enabled:=True;
Height:=21;
Parent:=Self;
Visible:=True;
Width:=175;
end;
panelTools.Show;

labelGlobalName:=TLabel.Create(Self);
with labelGlobalName do
begin
Align:=alLeft;
Enabled:=True;
Caption:=' Global ^ ';
Height:=20;
Layout:=tlCenter;
Parent:=panelTools;
Visible:=true;
end;
labelGlobalName.Show;


editGlobalName:=TEdit.Create(Self);
with editGlobalName do
begin
Align:=alLeft;
Enabled:=true;
Parent:=panelTools;
Visible:=true;
end;
editGlobalName.Show;

buttonFind:=TButton.Create(panelTools);
with buttonFind do
begin
Align:=alLeft;
Caption:='Find';
Enabled:=true;
onClick:=buttonFindClick;
Parent:=panelTools;
Visible:=true;
end;
buttonFind.show;

buttonMore:=TButton.Create(panelTools);
with buttonMore do
begin
Align:=alLeft;
Caption:='More';
Enabled:=false;
Parent:=panelTools;
Visible:=true;
end;
buttonMore.show;


// memo for text
memoGlobalLister:=Tmemo.Create(Self);
memoGlobalLister.Parent:=Self;
with memoGlobalLister do
begin
Align:=alClient;
BevelKind:=bkNone;
Enabled:=True;
Height:=150;
ReadOnly:=True;
ScrollBars:=ssBoth;
Width:=150;
end;
memoGlobalLister.Show;

end; // constructor

Destructor TKMPDGlobalLister.Destroy;
begin
inherited Destroy;
end;

// functions and procedures
function TKMPDGlobalLister.GetGlobalName: string;
begin
result:=GlobalName;
end;

function TKMPDGlobalLister.GetLastNodeAccessed: string;
begin
result:=LastNodeAccessed;
end;

procedure TKMPDGlobalLister.buttonFindClick(Sender: TObject);
begin

if editGlobalName.Text='' then exit;
messagedlg(editglobalname.Text,mterror,[mbok],0);

SetGlobalName(editGlobalName.Text);
MessageDlg('before buttonMoreClick',mtError,[mbOK],0);


SetLastNodeAccessed('');
buttonMore.Enabled:=false;
memoGlobalLister.Clear;

buttonMoreClick('');

end;

procedure TKMPDGlobalLister.buttonMoreClick(strVal: string);
var
i: integer;
intFontHeight: integer;
strLines: string;

begin

MessageDlg('strVal='+strVal,mtError,[mbOK],0);

if strVal='' then exit;
if RPCBroker=nil then exit;

// determine number of lines that can be displayed within the visible
// part of memo
if memoGlobalLister.Font.Height>-1 then
intFontHeight:=memoGlobalLister.Font.Height
else
intFontHeight:=memoGlobalLister.Font.Size*memoGlobalLister.Font.PixelsPerInch div 72;

intFontHeight:=(memoGlobalLister.ClientHeight div intFontHeight);
strLines:=Piece(FloatToStr(intFontHeight*0.75),'.',1);

with RPCBroker do
begin
RemoteProcedure:='KMPD GLOBAL LIST';
Param[0].Ptype:=literal;
Param[0].Value:=strVal;
Param[1].Ptype:=literal;
Param[1].Value:=GetLastNodeAccessed;
Param[2].Ptype:=literal;
Param[2].Value:=strLines;
try
Call;
except
MessageDlg('Unable to access Remote Procedure [KMPD GLOBAL LIST].',
mtError,[mbOK],0);
exit;
end;
// if error
// if ErrorCheck(Results[0],1,3)>0 then exit;

// btnPrint.Enabled:=True;

for i:=1 to Results.Count-1 do
MemoGlobalLister.Lines.Add(Results);

SetLastNodeAccessed(Results[0]);

// if end of global
if GetLastNodeAccessed='***end of list***' then
begin
memoGlobalLister.Lines.Add(GetLastNodeAccessed);
buttonMore.Enabled:=False;
end
else
begin
buttonMore.Enabled:=True;
buttonMore.Hint:='More';
// Panel1.Caption:='Press the More button to continue. You may also highlight and Print listing.';
end;
end;
end;


procedure TKMPDGlobalLister.SetGlobalName(strVal: string);
begin
GlobalName:=strVal;
end;

procedure TKMPDGlobalLister.SetLastNodeAccessed(strVal: string);
begin
LastNodeAccessed:=strVal;
end;

procedure Register;
begin
RegisterComponents('Capacity Planning', [TKMPDGlobalLister]);
end;

end.

 

[Zathras]

You have not defined any storage for the value you want to store/retrieve by the property "GlobalName"

Or to say it another way, the act of accessing the property "GlobalName" causes the function GetGlobalName to be invoked. Inside the function GetGlobalName you are accessing the property "GlobalName" recursively. This causes the stack overflow.

You need to define a string variable (e.g. FGlobalName) and change the getter and setter to reference that variable instead of referencing themselves.

procedure TKMPDGlobalLister.SetGlobalName(strVal: string);
  begin
    FGlobalName:=strVal;
  end;

function TKMPDGlobalLister.GetGlobalName: string;
  begin
    result:=FGlobalName;
  end;

 

[rkamarowski]

that did it.

thank you Zathras.