After experiencing it myself, I did a quick search and found that SelectionChanged will bubble from a ComboBox to a parent TabControl if left unhandled in:
In C# WPF, why is my TabControl's SelectionChanged event firing too often?
My question is why? What is the reasoning behind this? I feel like I'm missing something pretty important about WPF and events.
Most events in WPF will bubble (or tunnel) until someone sets Handled=true on the event args. The upside of this is that suppose you had multiple comboboxes within a single tab control - you could in a single place handle changes to all of those boxes. You can do this in addition to handling the event seperately on each ComboBox or also handling a consolidated event even higher up in the tree like monitoring all ComboBoxes within the entire window.
This is what WPF calls "routed events". For a good intro to the topic, check out http://msdn.microsoft.com/en-us/library/ms742806.aspx
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I'm trying to build a WPF control inheriting from Selector and I want to change the state of the control when one of its items are selected in the design surface. Despite hooking on a debugger, I can't seem to capture any useful events from the control. I've managed to capture it being initialised and the wrappers for its child elements being initialised around the items of the selection, but I can't see any change of state, or event being triggered when the control is selected.
Importantly, I want to detect when the item is selected either by the user selecting the control in the design view or in the markup.
I'm trying to achieve a behaviour like that of the TabControl, where selecting a tab brings it to the front and exposes any content associated with the tab. I can't fathom how it works at design-time though.
What do I need to do to detect that a control is selected?
Anyway to view all the events triggered specifically for a ui control.
I have integrated WPF toolkit extended into my application and currently facing an issue where the TimePicker does not trigger the ValueChanged unless it loses focus. that would be understandable but it has buttons in the control that changes the value ... so losing focus is not ideal as I would require to click on another control.
This is the first time I get this type of issue but there is a lot of times where I am not too positive which event I want to use so I just put a bunch of events with breakpoints and see which one gets hit with the ideal moment.
For that reason, I am curious to know if there is any sort of debugger tool or something similar that can register/show all the events being hit without me putting a breakpoint in every event or modifying the controls code ?
If ValueChanged is a RoutedEvent you could use a tool like snoop. http://snoopwpf.codeplex.com/
the events tab will show you events as they are triggered (note that you'll have to check off the event that you want to listen to in the dropdown.
I have a Window with many items in it, is there a Window or Grid Event to tell if the user has changed any textbox, combobox, radiobutton, checkbutton etc? I don't want to go through each item and add SelectionChanged event as this is just to tell if anything has changed since the data was last saved.
I think you should implement INotifyPropertyChanged interface which notify you once any property changed.
Here is an example that describes "Bind Better With INotifyProperty". This example is for a Windows App, but hope it would give you an idea.
Doing your job in this way is much elegant than adding events for each controls.
I've created a prototype app with a Listview bound to an ObservableCollection programmatically through it's itemsource property. Everything was working well until a day ago when the ListView stopped raising SelectionChanged events after the first time the event is raised. Eg. Select a row in the ListView, SelectionChanged event is raised, UI selects the first row in the ListView no matter what you do, then any attempts to select a row have absolutely no effect on the ListView, either in terms of selecting the row clicked on, or raising events.
So far I've established that if I remove all superflous code from the window, it does not solve the problem. If I transplant the code to a new project, it does not solve the problem.
However, if I re-implement the same code by hand in a new project, the problem does not present, but the code seems identical when compared with Beyond Compare.
I also got the problem to partially disapate by clearing all selections from the listview inside the SelectionChanged event handler, which seems to resolve the issue, but means that rows never appear as selected in the Listview.
I'm at wit's end with this.
If you're using duplicate items with value types(include ref. type string also), this problem could arise as they compare the values. You can wrap your item in a class to show that the items are different. But I don't know why it worked in the new application you've created. May be you could've changed the itemssource.
I have a System.Windows.Forms.ComboBox on a form and I want to capture the event just before the ComboBox's menu is displayed (something like "DroppingDown"). I can't seem to find a suitable event.
Is capturing this type of event possible with a ComboBox?
The ComboBox should have a DropDown Event. If I am not mistaken, this event should fire immediately when the drop down list starts to show.
What exactly are you wanting to accomplish immediately before the drop down shows that necessitates your capturing of such an event?