In this question I asked about adding TabItems dynamically to a TabControl
the ItemsSource are from ObservableCollection<Village>..
My question is if added a button to any TabItem, this button will have the DataContext of its container TabItem, how could I implement the Click event for this button?
If you have added the Button to the DataTemplate, then on your Button_Click method you can easily get the 'Village' datacontext.
void Button_Click(object sender, RoutedEventArgs e)
{
Village clickedVillage = ((Button)sender).DataContext as Village;
//Do whatever you want to do with the Village
}
But again, the above solution is not the best way to go for this problem. MVVM pattern would expect a ICommand in your Village (Or its container class) and you will bind that command to the Button.Command property so there wont be any code-behind at all. Or in other words your XAML will be more cleaner and ViewModel will get more self-contained in terms of properties and actions.
Related
So i am build simple Clipboard manager.
Every ListViewItem come from Clipboard.GetText and my application minimize to Tray and when double click on its Icon the application jump and i want to focus become on the first ListViewItem in order to be able to navigate with Up & Down arrows.
This is my ListView:
ListView myListView;
Model List:
public ObservableCollection<string> Clipboards
Window Loaded event:
private void Window_Loaded(object sender, RoutedEventArgs e)
{
if (viewModel.Clipboards.Count != 0)
myListView.ScrollIntoView(myListView.Items[0]);
myListView.Focus();
}
So currently when i open int the first time the application, the Focus is not on any ListViewItem and in the next time the focus is on the last selected/click ListViewItem and not on the first one.
It looks like you have your ViewModel in the code behind. This is not good MVVM standard.
Maybe this could be helpful
How can I set the focus to a ListBox properly on load if it uses databinding?
From what I see you are not focusing any ListViewItem but the ListView itself. I think this is your mistake. To focus the item you have to get it's container. The objects in the ItemsSource are actually the data itself and no the UIElement to render. To draw this data or add it to the visual tree for rendering, the ItemsControl will generate a container for the data e.g. a ListViewItem. Only the UIElement can receive focus, that's why the UIElement exposes the Focus() method. You have to use the ItemContainerGenarator to retrieve this container for your data:
ListView myListView;
(myListView.ItemsPanel as VirtualizingPanel)?.BringIndexIntoViewPublic(0);
myListView.Dispatcher.Invoke(new Action(
() =>
{
ListBoxItem dataContainer = myListView.ItemContainerGenerator.ContainerFromIndex(0) as ListBoxItem;
dataContainer?.Focus();
}), DispatcherPriority.ContextIdle);
This example will move the focus to the first element in the ListView.
Not finding a move event or redraw event in the FrameworkElement class. And Google not helping either. So...
I have a custom ItemsControl populated by an observable collection in the VM. The ItemsControl itself leverages the
<i:Interaction.Behaviors>
<ei:MouseDragElementBehavior ConstrainToParentBounds="True"/>
</i:Interaction.Behaviors>
behavior so the user can drag around the whole assembly.
When the user moves the assembly, I want to be notified by each item as the item is repositioned as a result of the assembly moving. So far I have tried registering for
this.myItem.LayoutUpdated += this.OnSomethingNeedsToUpdate;
but it doesn't seem to fire as I drag the assembly around.
Also
this.myItem.MouseMove += this.OnSomethingNeedsToUpdate;
only works if I mouse into the item which is not good enough. Because I am moving the ItemsControl and then have to go mouse into the item to get the event to fire.
Any ideas? Can I look to some ancestor in the visual tree for help in the form of a OneOfMyDecendantsWasRedrawn event or similar? Again I am trying to be notified when an item moves not be notified when the assembly moves.
I would say your best bet would be to add the MouseDragElementBehavior to your custom ItemsControl in code instead of in the Xaml. Here is how this might look (using a Grid since that is easier to demo):
public class DraggableGrid : Grid
{
public DraggableGrid()
{
Loaded += new RoutedEventHandler(DraggableGrid_Loaded);
}
void DraggableGrid_Loaded(object sender, RoutedEventArgs e)
{
MouseDragElementBehavior dragable = new MouseDragElementBehavior();
Interaction.GetBehaviors(this).Add(dragable);
dragable.Dragging += new MouseEventHandler(dragable_Dragging);
}
void dragable_Dragging(object sender, MouseEventArgs e)
{
// Custom Code Here
}
}
In the section that says Custom Code Here you would loop through you Items and notify them that they are being dragged.
I ended up writting another behavior for the individual items I care about and then wrote a LINQ query to search up the visual tree looking for ancestors with the MouseDragElementBehavior attached to them. That query found the ItemsControl since it was an eventual parent of the Item. I was then able to register for the Dragging event as desried.
Thanks again to Bryant for providing the solution over here.
I have a ContentControl element whose ContentTemplate is determined at run time from the Resource Dictionary. In the datatemplate I have a visual (Convas) and what I want is to also have a button in datatemplate which when clicked should print the visual element(canvas).
As I said that the DateTemplate is inside the Resource Dictionary so How can I write a Code on Click Event of that button and where it should be?
Any response would be much appreciated.
Sounds like you can use the Button.Click attached event. Just add it to the ContentControl.
<ContentControl
Button.Click="Button_Click"
ContentTemplate="<template with a button>"
/>
and the handler:
private void Button_Click(object sender, RoutedEventArgs e)
{
}
If you have multiple buttons in your template, you can use e.Source to figure it out. And I think you can use MouseButtonEventArgs instead.
I have a Grid with many TextBoxes and I want to call NotifyPropertyChanged() method to update some other controls everytime one of these TextBox-es changed the value = lost the focus (I don't want to use PropertyChanged as UpdateSourceTrigger)
This is what I can do:
<Grid TextBoxBase.TextChanged="My_TextChanged" >
...
</Grid>
I need something like:
TextBoxBase.OnLostFocus
Use the lost focus event
TextBox.LostFocus="OnTextBoxLostFocus"
Filter on textboxes ;)
private void OnTextBoxLostFocus(object sender, RoutedEventArgs e)
{
if(!(e.OriginalSource is TextBox))
return;
//Do stuff
}
If your properties are not changed, your Textboxes will not be updated however. You should consider mutating the data those other TextBoxes are bound to, instead of using LostFocus to update your model.
Good luck!
TextBoxBase.LostFocus is, I suspect, the event you're looking for.
It's listed here: http://msdn.microsoft.com/en-us/library/system.windows.controls.primitives.textboxbase_events.aspx - but it's defined on UIElement - so you possibly want to try UIElement.LostFocus if the above doesn't work in markup.
OK, so, I have a ListView-derived control that changes Grouping and ItemsSource on the fly. When I group such that the scrollbars dissapear, and then change my ItemsSource to a different ICollectionView, my scrollbars do not return.
The basic problem is that ListView changes to a VirtualizedStackPanel when grouping is activated and does not change back when grouping is de-activated.
I don't mind that virtualization is disabled when grouping--this is not a problem. What I need is a way to make the ListView regenerate it's ItemPanel when I change the ItemsSource.
Could you add an event handler to the SourceUpdated event and then reset the ItemsPanelTemplate to a template defined in your Resources?
Something like:
public MyWindow()
{
InitializeComponent();
MyListView.SourceUpdated += new EventHandler<DataTransferEventArgs>( OnSourceUpdated );
}
void OnSourceUpdated( object sender, DataTransferEventArgs e )
{
MyListView.ItemsPanel = (ItemsPanelTemplate)Resources["MyItemsPanelTemplate"];
}