您似乎要清除已应用的过滤器.要删除已应用的过滤器，商店提供了 clearFilter() 方法.您可以将其混合到类似于以下内容的代码中:

It looks like you want to clear the filter you already applied. To remove filters that have been applied there is a clearFilter() method available on the store. You can mix that into your code similar to this:

comboModule.clearValue();  
// new line to clear any filter applied to the store
comboModule.getStore().clearFilter(true);  
comboModule.getStore().filter('courseId',combo.getValue());