消息的困惑？WM_USER

[gyj_china]

interface

uses
...
//自定义消息
const WM_PressOK = WM_USER+100;

type
TMainForm = class(TForm)
...
public
procedure PressOK(var Msg: TMessage); message WM_PressOK;
//这里出错,出错信息如下：
//Unsatisfied forward or external declaration:'TMainForm.PressOK'
end;

//如果注释下面的这条type语句就可以通过
type
MyCall = function():integer;stdcall;
end;

var
MainForm: TMainForm;

implementation
...
------------------------------------------------------------
请问如何解决这个问题。

[gyj_china]

在使用过程中我发现出掉type后面的end;
然后注释掉public中的
procedure PressOK(var Msg: TMessage); message WM_PressOK;
就可以了，要不去掉
type
MyCall = function():integer;stdcall;
end;
这是为什么？

[yansea]

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
Dialogs;

const WM_PressOK = WM_USER+100;

type
TForm1 = class(TForm)
private
{ Private declarations }
public
{ Public declarations }
procedure PressOK(var Msg: TMessage); message WM_PressOK;
end;

type
MyCall = function(a:integer):integer;stdcall;//没有end

var
Form1: TForm1;

implementation

{$R *.dfm}


procedure TForm1.PressOK(var Msg: TMessage);
begin
//
end;

end.