(*
--- english -------------------------------------------------------------------
This is a component, so you are free to install it but must not: you can also
dynamically create an instance of it at runtime.
--- german --------------------------------------------------------------------
Es handelt sich hier um eine Komponente. Sie können es wie gewonnt installieren
oder einfach eine Instanz von der Objektklasse erst zur Laufzeit erzeugen.
*)
unit UNoCloseForm;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;
type
TNoCloseForm = class(TComponent)
private
{ Private declarations }
FCloseEnabled: boolean;
procedure SetCloseEnabled (Value: boolean);
protected
{ Protected declarations }
public
{ Public declarations }
constructor Create (AOwner: TComponent); override;
destructor Destroy; override;
procedure Toggle;
published
{ Published declarations }
property CloseEnabled: boolean read FCloseEnabled write SetCloseEnabled default False;
end;
procedure Register;
implementation
type THackWinControl = class (TWinControl);
constructor TNoCloseForm.Create (AOwner: TComponent);
begin
inherited Create (AOwner);
FCloseEnabled := False;
Toggle;
end;
destructor TNoCloseForm.Destroy;
begin
if (csDesigning in ComponentState) then
CloseEnabled:=True;
inherited Destroy;
end;
procedure TNoCloseForm.SetCloseEnabled (Value: boolean);
begin
if Value<>FCloseEnabled then
try
Toggle;
FCloseEnabled := Value;
except end;
end;
procedure TNoCloseForm.Toggle;
var WCTRL: THackWinControl; LI: LongInt;
begin
if not Assigned(Owner) or (csDesigning in ComponentState) then Exit;
WCTRL := THackWinControl (Owner);
LI := GetClassLong(WCTRL.Handle, GCL_STYLE);
LI := LI xor CS_NOCLOSE;
SetClassLong(WCTRL.Handle, GCL_STYLE, LI);
WCTRL.RecreateWnd;
end;
procedure Register;
begin
RegisterComponents('Samples', [TNoCloseForm]);
end;
end.