There are a lot of events that styleText can listen to and handle using _listeners of different kinds.
How can I find out which events fired when? For example, key event, line event, paint event, and so forth. Here are the listeners available:
addBidiSegmentListener
addExtendedModifyListener
addLineBackgroundListener
addLineStyleListener
addModifyListener
addPaintObjectListener
addSelectionListener
addVerifyKeyListener
addVerifyListener
addWordMovementListener
Thanks.
You need the "SWT Custom Controls" from the Eclipse Examples. Follow this page on how to set it up.
Then open the SWT Custom Controls view. Select the tab StyledText. Here you can select all listeners and simply try for yourself. Do something in the editor, and watch the output from the listeners. Very useful tools.
Related
Imagine a Visual Studio type user interface in which there is a left pane and a right pane. I need to send a message/event that originates in the left pane to an element in the right pane. As a WPF newbie, I have the following linked questions:
Can this be done using bubbling and tunneling events?
If the answer is 'yes', which is better: bubbling/tunneling, or Prism's event aggregator?
I use Event Aggregation to notify my 'panes' of events that happen and both need to respond.
So, for one example, I would subscribe both 'panes' to an event. Now, say I kick of a request to the database or webservice, and upon return of results I want to notify both 'panes' simultaneously that data has arrived. I can easily do this by publishing to my event, then both 'panes' will kick off whatever they need to.
I like this way, because then if I had another module dropped in the left 'pane', all I would need to do is subscribe to that event to respond to any data coming in.
I have a view in Silverlight which contains a telerik:RadGridView with a number of columns.
I have it wired up so that when the user double-clicks on one of these columns, an event is fired. However, I don't know what to put in the event handler.
private void RowClicked()
{
//What goes here?
}
All I wish to do is load a popup view over my current view, with a close button so that the user can return to the previous view. A simple idea that is surely done a billion times everywhere, but I cannot figure it out or find examples of this anywhere.
Can anyone help?
Thanks very much.
You can set a previous view as input parameter to "RowClicked()" method. You will have a reference on previous view in current method. You can use it via Commands (bind a command and a command parameter to some action/event).
I have an one more idea (if you have a lot of views): you can create a navigation service. It is an interface, which contains events and methods. You should use events for navigation and methods - for sending needed data. Everyone of view should implement this interface. Needed event will be raised under view via some action (for example: button click). As for events: you can create a custom event handler, there you will set a sender instance and needed parameters. You should create a Navigation manager, there you should create a property for selected view and subscribe on everyone event. If user want navigate to another view, he will do some action and system will raise an event. You can create a custom container for created views. This container you can use for getting created instance of needed view. As you know, creating a new instance is heavy for system: need a some time and system resources. Will be easy to get a created instance of view instead a create a new. For setting default data or refreshing a binding you can user a custom method, contractor for which will be added to navigation interface.
It is a simple idea, which I used in one project. As for others samples: You can find another navigation frameworks and custom classes in internet. But, process of creating an own system will give you a level up in your work experience.
I am looking for something that fire before the source is update
So instead of Binding.SourceUpdated I want Binding.PreviewSourceUpdated
I think you would need to handle this on your UI element and intercept the event if it's not ideal. So for example say you had a text box and a user pressed a key. You would use the PreviewTextInput (or similar preview) to see if you wanted the data changed - then mark the event has handled if you didn't.
The only other option that I know of is to use DataValidation and not allow the property to be updated for the model side.
I have implemented a UserControl. Then I would like to handle an event that is originally handled by Window (keyboard press). What is the best way to route the event caught by another component (higher in the components' tree)?
Thanks in advance for the replies and hints!
Cheers
It depends on the event you're trying to access. If it's a Preview event and the Window is setting e.Handled to true you'll need to use the method Alex suggests to circumvent the Window's handling of the tunneling. If it is a bubbling event (i.e. KeyDown) you don't need to do anything special since bubbling events hit the handlers on child elements first and go up the visual tree so the Window handler won't occur until after your UC's.
One thing you need to be careful with using Key events is that the event is only going to get picked up by your UC in the first place if the Focus is on or inside of it. This isn't something you need to worry about with things like Mouse events since they start at a specific location in the tree.
I believe you cannot gurantee that.
Window class is wrapping Win32 message-based event model and this will be the only WPF entity which will have access to those information.
I suggest that you create an attached property (which will be used by the Window) and implement the routing of the events yourself so that controls could subscribe to.
You can attach the routed handler specifying that you want to handle handled messages as well:
this.AddHandler(routedEvent, handler, true);
where this is an UIElement or derived class.
However there may still be events (key presses in this case) which don't make it past the window, not sure.
I hope this makes sense.
I have created several WPF User Controls. The lowest level item is 'PostItNote.xaml'. Next, I have a 'NotesGroup.xaml' file that has an ItemsControl bound to a List of PostItNotes. Above that, I have a 'ProgrammerControl.xaml' file. Each ProgrammerControl has a grid with four different NotesGroup user controls on it (and each NotesGroup contains 0-many PostItNotes.
Then, I have my main window. It also has an ItemsControl, bound to a list of Programmers.
So, you end up with a high level visual view of a list of programmers, each programmer has four groups of tickets, each group of tickets has many PostItNotes.
The trouble I'm having, is that I want to respond to a mouse click event in my mainWindow's code behind file.
I can add a MouseClick event into my PostItNote.xaml.vb file and that is getting called when the user clicks a PostItNote, and I can re-raise the event; but I can't seem to get the NotesGroup to listen for that event. I'm not sure if that's even the correct approach.
When the user clicks the PostItNote, I'm going to do a bunch of business-logic type stuff that the PostItNote control doesn't have a reference to/doesn't know about it.
Can anyone point me in the right direction?
You have a couple choices:
Use the PreviewXXX events which are fired during the "tunneling" phase of WPF event routing. The parent controls can always preview the events going down through them to children.
Use the more advanced approach to hooking up events leveraging the AddHandler method to which you can pass a parameter called "handledEventsToo" which basically means you want to know when the event happened "within" you even if some descendent element handled the event itself.
I am going to take a flyer here. You probably don't want to be handling the event that high up; not really anyway. You are catching the event at the lower levels, which is unavoidable. Consider invoking a routed command from the PostItNote click event handler.
The routed commands bubble up and tunnel down through the tree. You can have an architecture where a high-level handler can listen to a logical event (Opening a postit note perhaps?). The handler for this doesn't need to care where the command originates from. It might be from you clicking something, it might be from clicking on a toolbar button. Both are valid scenarios.
It sounds like you are creating some kind of custom UI, am I right? You want the application to respond to the users interactions. That is what the RoutedCommands are for.