Ошибка на OnClick:=ButClick;

unit Unit1;
 
{$mode objfpc}{$H+}
 
interface
 
uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
  ExtCtrls;
 
type
 
  { TForm1 }
 
  TForm1 = class(TForm)
    Button1: TButton;
    Label1: TLabel;
    Panel1: TPanel;
    Panel2: TPanel;
    procedure Button1Click(Sender: TObject);
    procedure ButClick(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.lfm}
 
{ TForm1 }
var
  a: array [0..11, 0..11] of integer;
 
 
procedure TForm1.ButClick(Sender: TObject);
begin
 ShowMessage('LYJ');
end;
 
 
procedure TForm1.Button1Click(Sender: TObject);
var
  n, i, ii, x, y: integer;
  But:TButton;
begin
  for i := 0 to 11 do
    for ii := 0 to 11 do
      a[i, ii] := 0;
  n := 0;
  randomize;
  while n < 10 do
  begin
    x := random(9) + 1;
    y := random(9) + 1;
    if a[x, y] = 0 then
    begin
      Inc(n);
      a[x, y] := 10;
    end;
  end;
 
  for i := 1 to 10 do
    for ii := 1 to 10 do
      if a[i, ii] = 0 then
      begin
        n := 0;
        if a[i + 1, ii] = 10 then
          Inc(n);
        if a[i - 1, ii] = 10 then
          Inc(n);
        if a[i, ii + 1] = 10 then
          Inc(n);
        if a[i, ii - 1] = 10 then
          Inc(n);
        if a[i + 1, ii - 1] = 10 then
          Inc(n);
        if a[i + 1, ii + 1] = 10 then
          Inc(n);
        if a[i - 1, ii + 1] = 10 then
          Inc(n);
        if a[i - 1, ii - 1] = 10 then
          Inc(n);
        a[i, ii] := n;
      end;
 
  for i := 1 to 10 do
    for ii := 1 to 10 do
    begin
      With But do
      begin
      But:=TButton.Create(Panel2);
      Tag:=(i-1)*10+(ii-1);
      Parent:=Panel2;
      Top:=(i-1)*30;
      Left:=(ii-1)*30;
      Width:=30;
      Height:=30;
      Caption:='';
      OnClick:=ButClick;
      end;
     Panel2.Canvas.TextOut(But.Top,But.Left,inttostr(a[i,ii]));
    end;
 
end;
 
 
end.