main.~pas

How to implement Windows CallBack with using delphi

unit main;

interface

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

const
  WM_FRAME_ARRIVE = WM_USER + 32;

type
  TMainForm = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    Button2: TButton;
    Label1: TLabel;
    Edit1: TEdit;
    Button3: TButton;
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
  private
   { Private declarations }
    Procedure WMFRAMEARRIVE(var Msg: TMessage); message WM_FRAME_ARRIVE;

  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation
{$R *.dfm}


function GetWindowHandle(const WindowCaption: PChar;
  const PartialCaption: Boolean = False): HWND;
var
  vlHWND: HWND;
  vlCaption: PChar;
  i: Integer;
begin
  Result := 0;
  GetMem(vlCaption, 255);
  vlHWND := GetWindow(FindWindow(nil, nil), 0);
  While (vlHWND <> 0) and (Result = 0) do begin
    i := GetWindowText(vlHWND, vlCaption, 255);
    if (i > 0) then begin
      if (UpperCase(String(vlCaption)) = UpperCase(String(WindowCaption))) then begin
        Result := vlHWND;
      end
      else begin
        if PartialCaption and Assigned(AnsiStrPos(vlCaption, WindowCaption)) then begin
          Result := vlHWND;
        end;
      end;
    end;
    vlHWND := GetWindow(vlHWND, GW_HWNDNEXT);
  end;
end;



function EnumWindowsFunc(Handle: THandle; List: TStringList) : boolean ; stdcall;
var
  caption: array[0..256] of Char;
begin
 if GetWindowText (Handle, Caption, SizeOf(Caption)-1) <> 0 then
 begin
  List.Add(Caption) ;
  SetWindowText(Handle, PChar('About - ' + Caption)) ;
 end;

 result :=True;
end;

procedure TMainForm.WMFRAMEARRIVE(var Msg: TMessage);
begin
  MainForm.Caption := 'AAA';

end;

procedure TMainForm.Button2Click(Sender: TObject);
var
  hwnd: THandle;
  PCameraSig: PChar;
  CameraSig: String;
  lParam: longint;
begin
  CameraSig := Edit1.Text;
  PCameraSig := PChar(CameraSig);

  hwnd := GetWindowHandle(PCameraSig);
  //If hwnd <> 0 then
  //  SetWindowText(hwnd, PChar('Test')) ;

  lParam := 40;
  Postmessage(hwnd, WM_FRAME_ARRIVE, 0, lParam);
end;

procedure TMainForm.Button3Click(Sender: TObject);
begin
  MainForm.Caption := Edit1.Text 
end;

end.