为什么我这样写看不到图标?

[prometheusphinx]

var
mbp: MSGBOXPARAMS;
begin
mbp.cbSize := SizeOf(MSGBOXPARAMS);
mbp.hwndOwner := Handle;
mbp.hInstance := HInstance;
mbp.lpszText := 'Hello World';
mbp.lpszCaption := 'Hello';
mbp.dwStyle := MB_USERICON;
mbp.lpszIcon := 'MAINICON'#0;
mbp.dwContextHelpId := 0;
mbp.dwLanguageId := LANG_NEUTRAL;
mbp.lpfnMsgBoxCallback := nil;
MessageBoxIndirect(mbp);
end;

[Past]

如果你要使用#0终止的字符串，必须用PChar型，然后用StrPCopy来赋值，如果是常量，可以简单的用类型强制转换，如：PChar('Hello')