Create a form with Windows API.

posted 9 Mar 2010, 04:01 by Delphi Basics
Not using VCL results in a smaller executable file size. Therefore, it may be required to create a form using only Windows API calls. It is possible to add functionality to the form; this will be discussed in a later snippet.

program Project1;

uses
  
windows, messages;

// Main Window Procedure
function MainWndProc(hWindow: HWND; Msg: UINT; wParam: wParam;
  lParam: lParam): LRESULT; stdcallexport;
var
  
ps: TPaintStruct;
begin
  
Result := 0;
  case Msg of
    
WM_PAINT:
      begin
        
BeginPaint(hWindow, ps);
        SetBkMode(ps.hdc, TRANSPARENT);
        TextOut(ps.hdc, 10, 10, 'Hello, World!', 13);
        EndPaint(hWindow, ps);
      end;
    WM_DESTROY: PostQuitMessage(0);
    else
      begin
        
Result := DefWindowProc(hWindow, Msg, wParam, lParam);
        Exit;
      end;
  end;
end;

// Main Procedure
var
  
wc: TWndClass;
  hWindow: HWND;
  Msg: TMsg;
begin
  
wc.lpszClassName := 'YourAppClass';
  wc.lpfnWndProc   := @MainWndProc;
  wc.Style         := CS_VREDRAW or CS_HREDRAW;
  wc.hInstance     := hInstance;
  wc.hIcon         := LoadIcon(0, IDI_APPLICATION);
  wc.hCursor       := LoadCursor(0, IDC_ARROW);
  wc.hbrBackground := (COLOR_WINDOW + 1);
  wc.lpszMenuName  := nil;
  wc.cbClsExtra    := 0;
  wc.cbWndExtra    := 0;
  RegisterClass(wc);
  hWindow := CreateWindowEx(WS_EX_CONTROLPARENT or WS_EX_WINDOWEDGE,
    'YourAppClass',
    'API',
    WS_VISIBLE or WS_CLIPSIBLINGS or
    
WS_CLIPCHILDREN or WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT, 0,
    400, 300,
    0,
    0,
    hInstance,
    nil);

  ShowWindow(hWindow, CmdShow);
  UpDateWindow(hWindow);

//Prevents the application from closing.
  while GetMessage(Msg, 0, 0, 0) do
  begin
    
TranslateMessage(Msg);
    DispatchMessage(Msg);
  end;
  Halt(Msg.wParam);
end.
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