API函数创建窗体问题？

Question

var
wnd:HWND;
wc:TWndClass;
begin
 wc.style:=CS_HREDRAW or CS_VREDRAW;
 wc.lpfnwndproc:=@DefWindowProc;
 wc.cbClsExtra:=0;
 wc.cbWndExtra:=0;
 wc.hInstance:=hInstance;
 wc.hIcon:=LoadIcon(0,IDI_QUESTION);
 wc.hCursor:=LoadCursor(0,IDC_ARROW);
 wc.hbrBackground:=HBRUSH(getStockObject(WHITE_BRUSH));
 wc.lpszMenuName:=nil;
 wc.lpszClassName:='wc'; RegisterClass(wc);//在这出错了？[Error] Unit1.pas(42): Incompatible types: 'TPersistentClass' and 'tagWNDCLASSA' wnd:=CreateWindow('newclass','New Form',WS_OVERLAPPEDWINDOW,100,100,300,150,0,0,Hinstance,nil);
 SHowWindow(wnd,SW_SHOWNORMAL);
 UpdateWindow(wnd);
end;

Answer 1

RegisterClass(wc);//在这出错了？[Error] Unit1.pas(42): Incompatible types: 'TPersistentClass' and 'tagWNDCLASSA' wnd:=CreateWindow('wc','New Form',WS_OVERLAPPEDWINDOW,100,100,300,150,0,0,Hinstance,nil); 
SHowWindow(wnd,SW_SHOWNORMAL); 
UpdateWindow(wnd); 
end;

Answer 2

RegisterClass(wc);
改成
Windows.RegisterClass(wc);

Answer 3

var 
wnd:HWND; 
wc:TWndClass; 
begin 
wc.style:=CS_HREDRAW or CS_VREDRAW; 
wc.lpfnwndproc:=@DefWindowProc; 
wc.cbClsExtra:=0; 
wc.cbWndExtra:=0; 
wc.hInstance:=hInstance; 
wc.hIcon:=LoadIcon(0,IDI_QUESTION); 
wc.hCursor:=LoadCursor(0,IDC_ARROW); 
wc.hbrBackground:=HBRUSH(getStockObject(WHITE_BRUSH)); 
wc.lpszMenuName:=nil; 
wc.lpszClassName:='wc'; Windows.RegisterClass(wc);//在这出错了？[Error] Unit1.pas(42): Incompatible types: 'TPersistentClass' and 'tagWNDCLASSA' 
//Delphi中的RegisterClass与WIN32API的RegisterClasser不同
wnd:=CreateWindow('newclass','New Form',WS_OVERLAPPEDWINDOW,100,100,300,150,0,0,Hinstance,nil); 
SHowWindow(wnd,SW_SHOWNORMAL); 
UpdateWindow(wnd); 
end;

Answer 4

前面是不是引用呀RegisterClass（&wc）