Trigger on Lisibox list is not working

Hi,

       I dont want to show the Checkbox,in a listbox list  if the content is empty,Actually i am binding the grid column names to a  listbox

<ListBox ItemsSource="{Binding Columns, ElementName=Grid1}" MinHeight="200" <ListBox.ItemTemplate><DataTemplate><CheckBox Content="{Binding Header}"
                                                                    IsChecked="{Binding IsVisible, Mode=TwoWay}"><CheckBox.Triggers><Trigger  Property="CheckBox.Content"  Value="{x:Null}"><Setter Property="IsVisible" Value="false"/></Trigger></CheckBox.Triggers></CheckBox></DataTemplate></ListBox.ItemTemplate></ListBox>