DELPHI判断创建动态窗体函数，已存在则直接显示

//==============================================================================
// if mark=0 then Tform.show else Tform.showmodal
//==============================================================================

procedure OpenChildForm(FormClass:TFormClass;var Form:TForm;Mark:Integer=0);
begin
  if Mark=0 then
  begin
    if not Assigned(form) then Application.CreateForm(FormClass,Form);
    if Form.WindowState=wsminimized then Form.WindowState:=wsMaximized;
  end else begin
    form:=FormClass.Create(nil);
    Form.ShowModal;
    Form.Free;
  end;
end;