Communication between User Controls

I have a TabControl with two tabs. One tab has a list of stores and the other has a list of employees. On the store开发者_StackOverflow中文版 tab I have a button that displays all employees of the store; to do that, I want to switch to the other tab and invoke a showEmployeesFromStore(store_id store) method from that tab's User Control. How would I do that?

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You've got the wrong mental model. Just because the user control isn't visible on the TabControl doesn't mean that the code is invisible as well. Just call the control's method in your code, it needs to be public of course. Then change the tab control's SelectedIndex property to switch the active tab page.

The button should not be part of the 1st user control. Actually it is better not to use a button but to just trigger an event when the user selects another store.

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I would expose an event on the store user control for SelectedStoreChanged or something to that effect. Pass back the newly selected store_id in the event delegate.

Subscribe to that event with your form. When the event fires, it is the form's job to decide with to do with that information. In this case, have it pull out the store_id from the store UserControl's SelectedStoreChanged event and pass it in to EmployeeUserControl.showEmployeesFromStore(store_id store)

Keep your controls ignorant of each other. Let the owner of the controls decide how to react to whatever events are raised by the controls. You'll sleep better with dreams of increased usability, better separation of subject areas, and more fewer working weekends due to untangling odd control flow... ;o)

Just realized I missed a detail. The button you're talking about should be on the form itself and not any of the user controls, assuming you don't want it to just update in real time using eventing described above. On button click, the form should go check StoreUserControl.SelectedStoreID() and pass the result to EmployeeUserControl.showEmployeesFromStore()