I'm trying to create an effect similar to the one used in the default email client on Windows phone. When a user taps the very left of a single listbox item, checkboxes appear to the left of all listbox items.
I'd like the appearance of the checkboxes to be fluid (ie requiring FluidLayout).
When I set up two states in a VisualStateGroup within the ItemTemplate of my items, I am unable to transition between states, as calling VisualStateManager.GoToState requires a view-object (for that item) which I don't have.
How do I make checkboxes appear fluidly inside of all items of a ListBox?
Related
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.
I have a tree view with checkboxes bounded to a property by name Ischecked in the corresponding view model,and whose content will be loaded on demand.Now when ever user checks the box,in the Ischecked setter property I add the checked treeview item into another Generic List(When a node is unchecked,It is removed from the List).Now I have two buttons namely select and deselect button.So when user checks different nodes and press select I will update the List box in the same usercontrol with the Generic List that I had previously.
How do I uncheck the corresponing treeview Items when user wants to remove few items from List box.Also am I doing the right way?
In WPF I have a TreeView control where a particular item can be selected either by the user selecting the item directly in the tree view or by clicking on a screen control. The tree view is displaying a list of elements that are being displayed on a user defined form, basically a form designer application.
Here is my problem. When the user clicks on a screen control it calls a method that returns the TreeViewItem that represents the element. It then sets the IsSelected property to true for this element. It correctly changes the visual indicator in the TreeView and it raised the SelectedItemChanged event in the TreeView. This is all good.
However, it appears that somewhere behind the scenes the TreeView still thinks the previous item is selected. Here is why I have come to this conclusion. If I select ElementA by clicking on it in the TreeView is it correctly selected. If I then select ElementB by clicking on the screen control and programmatically setting the IsSelected property for the ElementB TreeViewItem it appears to have selected it correctly. Now if I select ElementA again by clicking on it in the TreeView it does nothing. The SelectedItemChanged event is not raised and the reverse selection box that indicates the selected item stays on ElementB. If I click on ElementB in the TreeView it also does not raise the SelectedItemChanged event, however it does not appear to update the internal flag since if I then click on ElementA on the TreeView it processes it correctly and raises the event.
The only workaround that I have found for this is in the SelectedItemChanged event handler to call the Focus method for the now selected TreeViewItem. If I do this I get the expected behaviour when I select screen controls and programmatically change the selected TreeViewItem.
This is not an acceptable solution though as it creates focus change flicker. When I select items on my form window the focus goes to the TreeView control and then back to the form, causing flicker and slight delay.
Anyone have any indeas.
Update
As requested here is some code. Here is my method of my Explorer window which is the manager of the TreeView in question.
public bool SelectItemByName(String controlName)
{
bool fReturn = false;
TreeViewItem tviToSelect = FindItemByName(_tviMaster, controlName);
if (tviToSelect != null && _tviSelectedItem != tviToSelect)
{
tviToSelect.IsSelected = true;
// Make sure the selected item is visible in the TreeView by expanding all of the parent nodes
ExpandAllParents(tviToSelect);
tviToSelect.BringIntoView();
fReturn = true;
}
return fReturn;
}
Every element has a unique identifier that I use as a cross reference between different areas of the interface. When you click a screen control it uses its identifier to find the cooresponding TreeViewItem in the TreeView. Then this code sets it as selected.
Then in my SelectedItemChanged event handler I had to include the following line.
_tviSelectedItem.Focus();
This fixes my initial issue but introducing the unwant screen flicker.
To recap, I select ElementA in the TreeView directly, then select one or more other elements in the form designer which in turn calls SelectItemByName to programatically set the selected item. All visual indicators show that this worked. In the TreeView the highlighted item changes to the new item that is selected. After selecting any number of elements through the form designer interface if you select ElementA by clicking on it directly in the TreeView it does nothing. It does not get highlighted and it does not fire the SelectedItemChanged event. If you inspect the SelectedItem and SelectedValue properties of the TreeView they all correctly coorespond to the item that was programmatically selected. However, the control somewhere appears to think that ElementA is still selected and doesn't recognize that the selection is changing.
I cannot believe that other people haven't run into this. It appears to be a significant flaw in the TreeView contol in WPF. Not sure if WinForms has the same issue or not.
Each TreeViewItem has an IsSelected property, and I suspect the old one isn't getting set to false. Try setting it to false whenever you set the new item to true.
var currentItem = treeView.ItemContainerGenerator
.ContainerFromItem(treeView.SelectedItem) as TreeViewItem;
currentItem.IsSelected = false;
If that doesn't work, try setting focus on the newly selected item at the same time as when you select it. Don't forget that WPF also has two focus scopes: Logical Focus and Keyboard Focus. You may need to set both.
treeViewItem.Focus(); // Sets Logical Focus
Keyboard.Focus(treeViewItem); // Sets Keyboard Focus
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.
I have a Silverlight 4 application that uses multiple tabs. On Tab 1 I allow the user to select items from a grid, right click and select a context menu item that sends the items to a different grid on Tab 2. However, if the user has not clicked on Tab 2 yet, the grid I am trying to add items to does not exist yet.
What is the most elegant way to make sure that all objects on the second grid are instantiated even if the user has not selected the tab yet?
Thanks,
-Scott
Assuming you are adding items to data grid of some sort then the way to go is to add your items to an ObservableCollection and then data bind the grid to the collection.
That way you don't have to worry about whether the grid is actually visible or not and it will update itself when it does become visible.
Instead of trying to prepopulate the grid on tab2 with data that does not yet exist, you could use the MVVM pattern.
Tab1 could be view1 of viewModel1. Tab2 could be view2 for viewModel2. When view1 updates viewModel1, ViewModel1 updates ViewModel2, which, in turn, updates view2. Then, you only need to set bindings for the visibility, isEnabled, and ItemsSource properties.