《windows程序设计》文本输出（02）

获取设备环境句柄：

方法一：
hdc  = BeginPaint(hwnd, &ps);
    //使用GDI函数
EndPaint(hwnd, &ps);

方法二：
hdc = GetDc(hwnd);
    //使用GDI函数
ReleaseDc(hwnd, hdc)

代码如下：

program Project2;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils,
  windows,
  Winapi.Messages,
  Vcl.Dialogs;

function WindowProc(hwnd: hwnd; uMsg: UINT; wParam: wParam; lParam: lParam): LRESULT; stdcall;
var
  uHdc:HDC;
  ps:tagPAINTSTRUCT;
begin
  case uMsg of
    WM_CREATE:
      begin
        //ShowMessage('窗口创建完成');
      end;
    WM_PAINT:
      begin
        uhdc:=BeginPaint(hwnd,ps);
        TextOut(uHdc,0,0,'hello world',11);
        EndPaint(hwnd,ps);
      end;
  end;
  result := DefWindowProc(hwnd, uMsg, wParam, lParam);
end;

var
  swndClass: tagWNDCLASS;
  message: MSG;
  mHwnd: hwnd;

begin
  swndClass.cbClsExtra := 0; //窗口类扩展，无
  swndClass.cbWndExtra := 0; //窗口实例扩展
  swndClass.hbrBackground := COLOR_BACKGROUND; //窗口背景颜色黑色
  //LoadCursor()
  swndClass.hCursor := LoadCursor(0, IDC_ARROW); //窗口采用箭头光标
  swndClass.hIcon := LoadIcon(0, IDI_APPLICATION); //窗口最小化图标：采用缺省图标
  swndClass.hInstance := hInstance; //窗口实例句柄
  swndClass.lpfnWndProc := @WindowProc; //窗口处理函数
  swndClass.lpszClassName := 'myWnd'; //窗口类名
  swndClass.lpszMenuName := nil; //窗口菜单
  swndClass.style := CS_DBLCLKS; //窗口样式
  if RegisterClass(swndClass) = 0 then
  begin
    Writeln('windows class register error!');
    Exit;
  end;

  mHwnd := CreateWindowEx(0, 'myWnd', 'Delphi Windows', WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 544, 375, HWND_DESKTOP, 0, hInstance, 0);

  ShowWindow(mHwnd, SW_SHOW);
  UpdateWindow(mHwnd);
  while GetMessage(message, 0, 0, 0) do
  begin
    TranslateMessage(message);
    DispatchMessage(message);
  end;

  Readln;
end.