从BindingSource的文档：

From the BindingSource documentation:

典型地，在使用复杂的数据绑定   方案中，过滤器属性允许   您查看的一个子集   数据源。只有底层列出了   实施IBindingListView   接口支持过滤

Typically used in complex data-binding scenarios, the Filter property allows you to view a subset of the DataSource. Only underlying lists that implement the IBindingListView interface support filtering