I have a user control ProfileEditor in a WPF application. It has a number of input controls (TextBoxes, ComboBoxes, Radio Buttons, DatePicker). It will be used to add details for a new profile, or change details for an existing profile.
There is a requirement that if any changes have been made from the initial state (blank for a new profile, prefilled with current data for existing profile), if the user tries to leave the screen, they will first be warned that there are unsaved changes. This control will always be on a Page inside a Frame element, so leaving the screen will be either when navigating to a new Page in the Frame, or exiting the application.
What is the optimal setup for this?
I am thinking that there would be some event that would be attached to all data entry controls on the page (or maybe one event per control type) on the TextChanged or SelectionChanged events that would then set a page-level bool property as to whether or not changes have been made. Is there a way to set these using styles for all types of a control on the page at one time?
And then how would I catch the close screen event? Attach something to the Frame.Navigating event?
Related
Using CodenameOne,
I have a Form that the user needs to fill in. All of the components, however, are actually Containers that represent custom functionality. As an example, I would have a TextField alongside a Button on a Container, and I would use that Container as a "Component". This allows me to create more advanced functionality by combining existing Components.
A good example of where this is necessary is that of a custom date entry field existing out of 3 TextFields or a combination of TextFields and ComboBoxes.
I have a "Field" that has functionality for that of a Contact Component.
This all serves as a single "Unit" in order to allow the user to choose a contact or fill in their own. Buttons open Dialog popups, etc.
My problems comes with when the user uses the Android keyboard. Should this Contact Object be the second "Field" and the user presses the 'Next' button on the Android keyboard, the App does not know what field to give focus.
Furthermore, If one of the fields are a ComboBox or a Button and the user presses next to reach that Component, the keyboard doesn't close, and instead removes the 'Next' button, replacing it with a return button or an emoticon selector.
Below is an example situation:
The user would press on the first field, the Keyboard shows up, and when the user presses next, the keyboard's Next button dissapears, as the immediate next field happens to be a Button or ComboBox.
Is there a way to change the focusing index, or omit certain fields form ever gaining focus in this way? I tried making the entire thing a Component but that doesnt allow me to combine other Components. Even if it is possible to make the parent Container a Component, how would I solve this particular issue?
The default behavior is to use the "next focus down" for this functionality so just use setNextFocusDown(nextTextField) on each one of the components. Notice that a ComboBox won't work as expected although you might want to change that to an AutoCompleteTextField which would.
How can I reset my viewmodel when the user clicks new button on the view that has the viewmodel as it's datacontext?
For example:
If I have a view NewCustomer and upon save, the data is saved to the DB and the newly created account number is displayed. But when the user clicks the New button in the screen, I want the view (viewmodel) to be reinitialized. Or if the user clicked cancel in the screen to clear all changes.
How can I achieve this? I am using Prism 5.0 and Unity as my container.
If I used IRegionMemberLifetime, I can clear the viewmodel data when I navigate away and navigate again to the view (by setting the KeepAlive as false on clicking New button before navigating away). But I want the form to be cleared without navigating. Can this be done?
You could have a screen/workspaceViewModel, and another ViewModel wrapping your data.
So two classes: CarScreenViewModel and CarViewModel.
The CarScreenViewModel would have a property, say CurrentCar, which reflects what is currently selected in the screen. Then, when clicking the Create button, you simply set:
CurrentCar = new CarViewModel();
Resetting partially loaded data will only lead to behaviour that is hard to reproduce. It is better to start with a fresh instance.
Your standard approach will be something like below
ViewModels
CustomersContainerViewModel which contains
a collection of CustomerViewModel s
and ICommands like
CreateNewCustomer
DeleteExistingCustomer
UpdateExistingCustomer
Your View will contain
the CustomersContainerView which will contain
a collection of Customer Objects in your required UI element
a button to Create new customer (which will launch a new screen which contains the newCustomer fields it can also contain cancel, which will just close the form)
a button to delete (can also be a ContextMenu)
a button to update (can also be a ContextMenu) which will launch a customer form filled with details from DB.
Hopefully this makes some sense... Let me know if you have problem with any of the above
Update - Forgot to add. NewCustomer Command will add a new Customer object to your CustomerCollection and that should open a NewCustomer form (or whatever you chose) for user to input the customer details. Cancel/Delete will just remove that record from the collection. Delete will update the DB as well in addition
In my case
yourViewName.variableName.postValue("")
I have an application(Winform, TAB based MDI application), now we are adding few features. These Features are developed in WPF. A new form contains Element host, which will host this WPF User control. This newly added Form is displayed in every Tab's one corner. When application minimizes/Maximizes events are trigger, through these I am able to show or hide this new form. Also, this new form's Topmost Property is set true.
But when main form is still showing and when another application(like a note pad) is opened, the newly added form displayed over this notepad. The new form supposed to go behind the notepad, but it is always top.
Any suggestion on how to send it back.
Thank you,
Selected answer from
Detect when application becomes active post solved my problem.
I am also capturing
main.Deactivate += new EventHandler(main_Deactivate);
Thank you.
I'm just starting to use the composite application libraries for WPF. In my shell I have a region in a tabcontrol that is used to display different types of views. I also have a toolbar with buttons hooked up to commands, for example save. The commands are bound in my views, and the views have the canExecute and execute methods.
The idea is that when i click a tab, my tool bar buttons should be enabled or disabled according to the methods in the view. Problem is when I switch tabs the view is not getting the focus and the canExecute for that view doesn't get called. The toolbar buttons remain connected to the commands in the previously selected view, and reminds that way until i actually click on the new view
I'm stumped right now on how to force the view to get the focus. I've tried looking at the tab's content when the tabs SelectionChanged and setting the focus there but its not making a difference. Any ideas?
Try listening for the View.Loaded event, then call View.focus() in the handler. Wpf will not accept focus requests before an element is initialized and loaded. Since the SelectionChanged event is raised before the view is loaded, the focus request will just be ignored. The loaded event is called each time the element is shown after being hidden.
See this blog post for more information on focus:
http://www.julmar.com/blog/mark/PermaLink,guid,6e4769e5-a0b3-47b2-a142-6dfefd0c028e.aspx
I have a button which launches a "modal dialog" - it just creates a transparent grid covering everything, with the "dialog" created on top of that.
However I have a strange issue - if I double/triple click the button really fast (or add some delay in the event code), the button click event is executed multiple times, creating multiple overlapping modal dialogs. If the first action in my event is to disable the button (IsEnabled=false) it seems to prevent this.
My guess is that Silverlight is being multithreaded with input - it is not only recording the second click in another thread (while the button's click event is running), but it is jumping the gun by evaluating which control should be the target before the previous event has finished executing. Even though that event alters what control is at those mouse coordinates, it doesn't matter.
Does anyone know anything about this behavoir, or a way around it? If I have something like a save window, where the user clicks a save button, a blocking grid ("Saving...") is placed up while it saves, and then the whole "window" is closed, I'd like to avoid the user being able to queue up multiple save event clicks (this could lead to unpredictable program behavoir).
If you've ever worked with WinForms or WPF, this is expected behavior. Your button is broadcasting its Click event until your modal dialog covers it up. Unfortunately, there is some amount of time between your first click and when the modal dialog covers the button which allows multiple clicks to the original button.
You have two solution choices:
Disable the button after the first click and then re-enable after the modal dialog returns. You've already mentioned that this works.
Write code in the Event Handler of the button to determine if a modal dialog is already being displayed. This way, you're putting the responsibility in one location rather than splitting it up (disabling and re-enabling the button). This would be my preferred solution.
I think what you're seeing is the behaviour of Silverlight's routed events.
You can set the Handled property of the event arguments to true to prevent the event from bubbling.