Delphi 下调用Windows API 创建窗体

杨竹青

program delphi;
uses

windows,

messages;

const

hellostr='Hello World!';

{$R delphi.res}

//窗口消息处理函数.

function MyWinProc(hWnd:THandle;uMsg:UINT;wParam,lParam:Cardinal):Cardinal;exp

ort;stdcall;

var

hdca,hdcb:THandle; //设备描述表句柄.

rect:TRect; //矩形结构.

font:HFont;

ps:TPaintStruct; //绘图结构.

begin

result:=0;

case uMsg of

WM_PAINT:

begin

hdca:=BeginPaint(hWnd,ps);

SetBkMode(hdca, Transparent);

SetBkColor(hdca,GetBkColor(hdca));

GetClientRect(hWnd,rect); //获取窗口客户区的尺寸.

DrawText(hdca,Pchar(hellostr),-1,rect,DT_SINGLELINE or DT_CENTER or DT

_VCENTER);

// TextOut(hdc,100,40,hellostr,Length(hellostr));

EndPaint(hWnd,ps);

end;

WM_CREATE:

begin

hdcb := GetDC(hWnd);

font := CreateFont(45, 0, 0, 0, FW_normal, 0, 0, 0, ansi_charset, out

_default_precis, clip_default_precis,

default_quality, 34, PChar('Arial'));

SelectObject(hdcb, font);

ReleaseDC(hWnd, hdcb);

end;

WM_DESTROY:

PostQuitMessage(0)

else

//使用缺省的窗口消息处理函数.

result:=DefWindowProc(hWnd,uMsg,wParam,lParam);

end;

end;

//主程序开始.

var

Msg :TMsg; //消息结构.

hWnd,hInst :THandle; //Windows 窗口句柄.

WinClass :TWndClassEx; //Windows 窗口类结构.

begin

hInst:=GetModuleHandle(nil); // get the application instance

WinClass.cbSize:=SizeOf(TWndClassEx);

WinClass.lpszClassName:='MyWindow'; //类名.

WinClass.style:=CS_HREDRAW or CS_VREDRAW or CS_OWNDC;

WinClass.hInstance:=hInst; //程序的实例句柄.

//设置窗口消息处理函数.

WinClass.lpfnWndProc:=@MyWinProc; //窗口过程.

WinClass.cbClsExtra:=0; //以下两个域用于在类结构和Window

s内部保存的窗口结构

WinClass.cbWndExtra:=0; //中预留一些额外空间.

WinClass.hIcon:=LoadIcon(hInstance,MakeIntResource('MAINICON'));

WinClass.hIconsm:=LoadIcon(hInstance,MakeIntResource('MAINICON'));

WinClass.hCursor:=LoadCursor(0,IDC_Arrow);

//GetStockObject 获取一个图形对象,在这里是获取绘制窗口背景的刷子,返回一个白色刷

子的句柄.

WinClass.hbrBackground:=HBRUSH(GetStockObject(white_Brush));

WinClass.lpszMenuName:=nil; //指定窗口类菜单.

//向Windows 注册窗口类.

if RegisterClassEx(WinClass)=0 then

begin

MessageBox(0,'Registeration Error!','SDK/API',MB_OK);

Exit;

end;

//建立窗口对象.

hWnd:=CreateWindowEx(

WS_EX_OVERLAPPEDWINDOW, //扩展的窗口风格.

WinClass.lpszClassName, //类名.

'Hello Window', //窗口标题.

WS_OVERLAPPEDWINDOW, //窗口风格.

CW_USEDEFAULT, //窗口左上角相对于屏幕

左上角的初始位置x.

0, //....右y.

CW_USEDEFAULT, //窗口宽度x.

0, //窗口高度y.

0, //父窗口句柄.

0, //窗口菜单句柄.

hInst, //程序实例句柄.

nil); //创建参数指针.

if hWnd<>0 then

begin

ShowWindow(hWnd,SW_SHOWNORMAL); //显示窗口.

UpdateWindow(hWnd); //指示窗口刷新自己.

SetWindowPos(hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE + SWP_NOSIZE);

end

else

MessageBox(0,'Window not Created!','SDK/API',MB_OK);

//主消息循环程序.

while GetMessage(Msg,0,0,0) do

begin

TranslateMessage(Msg); //转换某些键盘消息.

DispatchMessage(Msg); //将消息发送给窗口过程.

end;

end.

其实Windows 编程是每个学写程序的人都要掌握的,学Delphi时也最好能先学习Windos编程(最少要知道).以上代码虽说不如在Delphi中直接来个New->Form来的快,但它能告诉你本质的东西.能让你更好的了解消息循环以及其他.而这些正是让New出来的窗体给掩盖的部分。