PHP DM Gate v0.9 » How check Event is Dummy?

f417support © (24.01.11 04:19) [0]

How check Event is Dummy? becase a lot of my code use

if Assigned(Form.OnMessage) then
begin
// Do SomeThing
// variable = Form.OnMessage(...), if OnMessage Is Dummy, Varible will not be correct
end;

<Цитата>
Vladimir Kladov © (24.01.11 15:36) [1]

If you do not want use NIL_EVENTS, you can check only Data field of the event:
if Assigned( TMethod( Form.OnMessage ).Data ) then ...

There only a problem with such check if you set you handler to a NIL object too.

<Цитата>
f417support © (25.01.11 04:00) [2]

if Assigned(Form.OnMessage) then
begin
MsgOk("Assigned");
end;
MsgOk Is Always called even use NIL_EVENTS

<Цитата>
Vladimir Kladov © (27.01.11 16:45) [3]

if Assigned( TMethod( Form.OnMessage ).Data ) then
ShowMsg( 'OK', MB_OK );

does work: no message 'OK' when OnMessage not assigned.

<Цитата>
f417support © (28.01.11 03:55) [4]

i have a lot of code in old style, i think if define NIL_EVENTS , old code can still work, it suite for me. otherwize, convert kol2.94 project to kol 3.00, it is a hard work. thank for your reply.

<Цитата>
Jon © (30.01.11 03:41) [5]

I do not understand - what should I see here?

program Test;

uses Windows, KOL;

var
Button1, Button2: PControl;

procedure Button1Click(Dummy: Pointer; Sender: PObj);
begin
if Assigned(TMethod(Applet.OnMessage).Data) then
ShowMsg('OK', MB_OK);
end;

procedure Button2Click(Dummy: Pointer; Sender: PObj);
begin
Applet.OnMessage := nil;
end;

function AppMessage(Dummy: Pointer; var Msg: tagMSG; var Rslt: Integer): Boolean;
var
Index: Integer;
begin
Result := False;
end;

begin
Applet := NewForm(nil, 'Test');
Applet.OnMessage := TOnMessage(MakeMethod(nil, @AppMessage));
Button1 := NewButton(Applet, 'Button1');
Button1.OnClick := TonEvent(MakeMethod(nil, @Button1Click));
Button2 := NewButton(Applet, 'Button2').PlaceRight;
Button2.OnClick := TonEvent(MakeMethod(nil, @Button2Click));
Run(Applet);
end.

<Цитата>
Vladimir Kladov © (30.01.11 18:37) [6]

Nothing. In your case Data always is nil.
When use MCK, it is usually an object which method is assigned as an even handler.
In case of non-MCK it is sufficient to pass something else then nil in MakeMethod. E.g.:

Applet := NewForm(nil, 'Test');
Applet.OnMessage := TOnMessage(MakeMethod(Applet, @AppMessage));
Button1 := NewButton(Applet, 'Button1');
Button1.OnClick := TonEvent(MakeMethod(Applet, @Button1Click));
Button2 := NewButton(Applet, 'Button2').PlaceRight;
Button2.OnClick := TonEvent(MakeMethod(Applet, @Button2Click));
Run(Applet);

<Цитата>