使MDI窗口有一个背景图象或使它平铺

确定你已在在你的主窗体对象中加入了下面的变量:

FClientInstance : TFarProc;

FPrevClientProc : TFarProc;

{ MDI的背景代码 }

procedure TMainForm.ClientWndProc(var Message: TMessage);

var

Dc : hDC;

Row : Integer;

Col : Integer;

begin

with Message do

case Msg of

WM_ERASEBKGND:

begin

Dc := TWMEraseBkGnd(Message).Dc;

// 在DC上平铺图象

for Row := 0 to ClientHeight div Image1.Picture.Height do

for Col := 0 to ClientWidth div Image1.Picture.Width do

BitBlt(Dc,

Col * Image1.Picture.Width,

Row * Image1.Picture.Height,

Image1.Picture.Width,

Image1.Picture.Height,

Image1.Picture.Bitmap.Canvas.Handle,

0,

0,

SRCCOPY);

Result := 1;

end;

else // 传递其他消息

Result := CallWindowProc(FPrevClientProc,

ClientHandle,

Msg,

wParam,

lParam);

end;

end;

- 在你的主窗体的OnShow事件中加入以下代码:

// MDI背景平铺代码，与WndProc链接

FClientInstance := MakeObjectInstance(ClientWndProc);

FPrevClientProc := Pointer(GetWindowLong(ClientHandle,GWL_WNDPROC));

SetWindowLong(ClientHandle,GWL_WNDPROC,LongInt(FClientInstance));

- 现在你有一个背景了!