DELPHI 开发原生WINDOW窗口程序(过程/面向对象)

一.DELPHI 开发原生WINDOW窗口程序(过程)
1.定义消息结构体TMessage(系统)
2.定义消息回调函数 WndProc
3.注册窗口信息到WINDOWS中(用到回调函数地址)
4.CreateWindow创建窗口
5.消息循环处理
program Project2;

uses
  Windows, Messages, SysUtils;

const
  AppName ='PascalHello';

function WindowProc(Window: HWnd; AMessage: UINT; WParam: WPARAM;
  LParam: LPARAM): LRESULT; stdcall; export;
var
  dc: hdc;
  ps: TPaintStruct;
  r: TRect;
begin
  WindowProc := 0;
  case AMessage of
    WM_PAINT:
      begin
        dc := BeginPaint(Window, ps);
        GetClientRect(Window, r);
        DrawText(dc, '使用PASCAL撰写的NATIVE WINDOW程序', -1, r,
          DT_SINGLELINE or DT_CENTER or DT_VCENTER);
        EndPaint(Window, ps);
        Exit;
      end;
    WM_Destroy:
      begin
        PostQuitMessage(0);
      end;
    WM_LBUTTONDOWN:
      begin
        MessageBox(0, 'LBUTTONDOWN Click.', nil, mb_Ok);
      end;
    end;

  WindowProc := DefWindowProc(Window, AMessage, WParam, LParam);
end;

function WinRegister: Boolean;
var
  WindowClass: WndClass;
begin
  WindowClass.style := cs_hRedraw or cs_vRedraw;
  WindowClass.lpfnWndProc := TFNWndProc(@WindowProc);
  WindowClass.cbClsExtra := 0;
  WindowClass.cbWndExtra := 0;
  WindowClass.hInstance := system.MainInstance;
  WindowClass.hIcon := LoadIcon(0, idi_Application);
  WindowClass.hCursor := LoadCursor(0, idc_Arrow);
  WindowClass.hbrBackground := GetStockObject(WHITE_BRUSH);
  WindowClass.lpszMenuName := nil;
  WindowClass.lpszClassName := AppName;

  Result := RegisterClass(WindowClass) <> 0;
end;

function WinCreate: HWnd;
var
  hWindow: HWnd;
begin
  hWindow := CreateWindow(AppName, 'Hell0 world Object Pascal Program',
              Ws_OverLappedWindow, cw_UseDefault, cw_UseDefault,cw_UseDefault,
              cw_UseDefault, 0, 0, system.MainInstance, nil);
  if hWindow <> 0 then
  begin
    ShowWindow(hWindow, CmdShow);
    ShowWindow(hWindow, SW_SHow);
    UpdateWindow(hWindow);
  end;

  Result := hWindow;
end;

var
  AMessage: TMsg;
  hWindow: HWnd;

begin
  if not WinRegister then
  begin
    MessageBox(0, 'Register Failed', nil, mb_Ok);
    Exit;
  end;

  hWinDow := WinCreate;

  if (Longint(hWindow) = 0 ) then
  begin
    MessageBox(0, 'WinCreate Failed', nil, mb_Ok);
    Exit;
  end;

  While GetMessage(AMessage, 0, 0, 0) do
  begin
    TranslateMessage(AMessage);
    DispatchMessage(AMessage);
  end;

  Halt(AMessage.wParam);
end.

二.面向对象改造：

DELPHI 开发原生WINDOW窗口程序(面向对象)
1.定义消息结构体TMessage(系统)
2.定义消息回调函数 WndProc
3.注册窗口信息到WINDOWS中(用到回调函数地址)
4.CreateWindow创建窗口
5.消息循环处理

program Project2;

uses
  Windows,
  Messages,
  SysUtils;
 
const
  AppName ='PascalHello';

Type
  TMyWindow = Class(TObject)
  private
    WindowClass: WndClass;
    hWindow: HWnd;
    AMessage: TMsg;
    function Winregister : Boolean;
    procedure CreateMyWindow;
  public
    FAppName: String;
    FWndProc: TFNWndProc;

    constructor Create;
    destructor Destroy; override;

    procedure WinCreate;
    procedure MyRun;

    property ApplicationName : string read FAppName;
    property WindowProcedure : TFNWndProc read FWndProc;

  end;

function WindowProc(Window: HWnd; AMessage: UINT; WParam: WPARAM;
  LParam: LPARAM): LRESULT; stdcall; export;
var
  dc: hdc;
  ps: TPaintStruct;
  r: TRect;
begin
  WindowProc := 0;
  case AMessage of
    WM_PAINT:
      begin
        dc := BeginPaint(Window, ps);
        GetClientRect(Window, r);
        DrawText(dc, '使用PASCAL撰写的NATIVE WINDOW程序， 利用面向对象技术进行编程。', -1, r,
          DT_SINGLELINE or DT_CENTER or DT_VCENTER);
        EndPaint(Window, ps);
        Exit;
      end;
    WM_Destroy:
      begin
        PostQuitMessage(0);
      end;
    WM_LBUTTONDOWN:
      begin
        MessageBox(0, 'LBUTTONDOWN Click.', nil, mb_Ok);
      end;
    end;

  WindowProc := DefWindowProc(Window, AMessage, WParam, LParam);
end;

var
  MyWindow : TMyWindow;

{ TMyWindow }

constructor TMyWindow.Create;
begin

end;

destructor TMyWindow.Destroy;
begin

  inherited;
end;

procedure TMyWindow.CreateMyWindow;
begin
  hWindow := CreateWindow(AppName, 'Hell0 world Object Pascal Program',
              Ws_OverLappedWindow, cw_UseDefault, cw_UseDefault,cw_UseDefault,
              cw_UseDefault, 0, 0, system.MainInstance, nil);

  if hWindow <> 0 then
  begin
    ShowWindow(hWindow, CmdShow);
    ShowWindow(hWindow, SW_SHow);
    UpdateWindow(hWindow);
  end;
end;

procedure TMyWindow.MyRun;
begin
  While GetMessage(AMessage, 0, 0, 0) do
  begin
    TranslateMessage(AMessage);
    DispatchMessage(AMessage);
  end;

  Halt(AMessage.wParam);
end;

procedure TMyWindow.WinCreate;
begin
  if Winregister then
    CreateMyWindow;
end;

function TMyWindow.Winregister: Boolean;
begin
  WindowClass.style := cs_hRedraw or cs_vRedraw;
  WindowClass.lpfnWndProc := TFNWndProc(@WindowProc);
  WindowClass.cbClsExtra := 0;
  WindowClass.cbWndExtra := 0;
  WindowClass.hInstance := system.MainInstance;
  WindowClass.hIcon := LoadIcon(0, idi_Application);
  WindowClass.hCursor := LoadCursor(0, idc_Arrow);
  WindowClass.hbrBackground := GetStockObject(WHITE_BRUSH);
  WindowClass.lpszMenuName := nil;
  WindowClass.lpszClassName := AppName;

  Result := RegisterClass(WindowClass) <> 0;
end;

begin
  MyWindow := TMyWindow.Create;
  MyWindow.FAppName := AppName;
  MyWindow.FWndProc := TFNWndProc(@WindowProc);
  MyWindow.WinCreate;

  try
    MyWindow.MyRun;
  finally
    FreeAndNil(MyWindow);
  end;
end.