I have two panes in my page (category and items). The category pane is basically a n-level tree view which controls what items are to be shown on the items pane on the right. So if I choose a category, the items panel on the right hand side will show all items in that particular category (in a datagrid). I am fetching the items from a WCF service in the SelectedItemChanged event.
Now the items grid in the right pane is an editable datagrid. So when a user has some unsaved changes in the grid and tries to change the category, I need to give him a warning message (message box with Ok/Cancel) and on cancel click, I need to suppress this category selection change.
Now, I have tried the the MouseLeftButtonDown event to suppress this, but it somehow doesn't seem to work.
I have refereed this link for the possible solutions.
Can anyone please suggest something?
At the end of your selectedItemChanged event, call [yourTreeView].ClearSelection()
This will give the appearance of the treeview not performing a selection, yet will react as a click.
Related
I am having a combo box control in which I had inserted three items(For instance X,Y,Z respectively). I want to show a dialog when "X" item in the combobox is clicked. In order show a dialog upon click on "X" item, I was able to handle it in "SelectionChanged" event. But the problem here is when I click on the same item no event is getting triggered and as a result I am not able to show a dialog on click on "X" item.
How can I accomplish this issue using MVVM pattern.
I am very new to WPF, please be kind with your answers.
I have a Region in the top left of the WPF application which I want to be my global button bar where the user chooses which screen they want to view, and the appropriate content will then be displayed in the main region. THere will also be a sub navigation region in the top right with sub-menu options within that screen, eg if the user clicked "Maintenance" from the main menu, the sub menu would show options for New, Update, Delete, Edit etc.
What I want to have is a way to create a custom menu bar by simply specifying a list of Text button names, and ICommand/Parameter pairs for the action to invoke on button click. The natural way to do this would be have a MenuButtonViewModel class with dependency properties Title, Command and CommandParameter. One more would also be needed, IsSelected, so there is some visual way for the user to see which screen you are currently on, so it needs to behave like a toggle button, but where only one button in the group can be selected at a time. I can then have a UserControl where the content of the bar binds to an ObservableCollection and uses data templates to render the button bar.
I have tried a few ways of doing this so far but cannot figure out a way that gives me the visual behaviour I want. These are my requirements
1) Button to change background to a different Brush OnMouseOver
2) When button is selected, a different Brush is displayed as the background until a new button in the group is selected, like a togglebutton IsSelected behaviour
3) Only one button in the group can be selected at a time
The ways I have tried to do this so far are
1) Extending RadioButton with my own class, adding dependency properties for command and commandparameter. Setting all controls to have the same group Id. Data template to override display of radio button to make it look like a visual button with triggers for mouseover and isselected.
This works fine, except for one thing. Once you select a radio button in a group, there is no way to deselect all options in the radio button group. So if you navigate to "maintenance" and then click the sub menu for "Countries" for example, then you are displayed the country maintenance screen. If you then go to a different area of the app and select "Deal Entry" from the main menu, you are taken to the deal entry screen. If you then click "Maintenance", it displays the generic "maintenance" content and brings back the sub menu control for maintenance, where "Country" is selected in the radio button group, but this is undesirable. When you navigate back to Maintenance, it should deselect all sub menu options, display the generic maintenance landing page content and let you select a sub menu option before displaying that screens content. The first time you load Maintenance, nothing is selected, but once you have chosen an option, then there is no way to have nothing selected again when you reload the maintenance screen.
2) I then tried extending a ListBox, styling it with a horizontal stackpanel for the content, each listboxitem is a menubuttonViewModel. This allows me to only select a single option at a time and to clear the selection when you navigate away from the page. It also lets me change the background when you mouse over each listboxitem.
The bit I can't get working with the listbox is to have the background different on the IsSelected trigger. There seems to be some trigger on the default ListBoxItem template that overrides anything you specify in CSS so no matter what trigger I put on the listboxitem or menubuttonviewmodel style, the background simply does not change. I think I need to redefine the data and content template for listboxitem, but only have it apply for this listbox, so it can't be a global template change to all listboxitems - as I want to be able to use listboxes elsewhere in the app without inheriting this behaviour.
Can anyone give their thoughts on these two approaches and how to perhaps solve the issues I'm having to make one of them work in the way I want, particularly if you can advise how I can override the content/data template for the listboxitems in my style so they do not use the default triggers, and I can get the IsSelected trigger working for me?
If I understood correctly, you would want to clear the selection on the RadioButtons from the Sub-Menu each time you navigate back from another Main Menu option.
In order to solve this, you could have every Radio Button "unchecked" by manually setting the RadioButton´s IsChecked property value to false. A possible solution could be the following:
If you want to clear any checked option from the Sub-Menu everytime you navigate to a different section of the Main Menu, you could first notify to the Sub-Menu´s ViewModel by publishing an event using the EventAggregator after selecting and clicking a different MainMenu button, from the SelectionChangedEventHandler method of the Main Menu´s ViewModel.
Therefore, the Sub-Menu EventHandler of the published event would update each RadioButton´s IsChecked property value to false, which it could be accomplished by using a "Two-Way" Binding between each IsChecked property defined on the View, and each boolean "RadioButton1IsChecked" property implemented on the ViewModel.
I hope this helped you.
The image above depicts a ListBox. You can see the rows are able to be selected. However they should be not selectable when i click on the row, but i have no idea on how to solve this problem.
My question is, how to make the listbox rows above not able to be selected?
The easiest solution would be to use an ItemsControl instead of a ListBox. It's a similar control that doesn't allow selection.
You can retemplate the control, removing the selected state animation. Easy to do if you have Blend.
Right click on the ListBox, select Edit Additional Templates | Edit Generated Item Container | Edit A Copy. Switch to the States tab and choose the Selected state. (For Silverlight) you should see that the Rectangle "fillColor2" has a red circle, showing it's Opacity property is animated in this state. Expand fillColor2, click Opacity, and press delete. You can also do the same for the Focused state (and MouseOver state, if you don't want a mouseover effect)
I'm wondering if I can make fake sections in the popup menu:
The rule would be, if the 5th character of the displayed item is different from the 5th char of the previous item in the menu, it has to be highlighted
What do you think?
Thanks!
To achieve this would be a hack.
Normally the items that appear in the popup part of a combo box will be an instantiated data template, and each gets its own data item and has no clue or knowledge of the other items in the list, so you couldn't use a converter or anything else to achieve this behavior.
What you could do though is inject (attach) your own control into the popup part of the combo box, and take over the rendering of the data items. How you do this will depend upon which combo box you are using (i.e. MS or some other vendor's) and would be a whole new question.
Would that be easier if I were to create my own combobox as follow:
a TextBox associated with a Button that when pushed would popup a datagrid in which I could implement this conditional formatting?
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