后两句为什么不能建了窗体??
procedure Tmainform.Button1Click(Sender: TObject);
var
child : Tchildform;
begin
Child := TChildForm.Create(Mainform);
Child := TChildForm.Create(Application);
Child := TChildForm.Create(nil);
Child := TChildForm.Create(ChildForm);
end;
主窗体是mainform1,子窗体是childform