Develop Reference

Flyout's "Light Dismissal" Causing 2 Taps to be Required to Open Next Flyout

I have two buttons that show Flyouts when clicked. I am displaying them the same way as demonstrated in the XAML UI Basics sample:
private void ButtonTapped(object sender, TappedRoutedEventArgs e)
{
FrameworkElement element = sender as FrameworkElement;
if (element != null)
{
FlyoutBase.ShowAttachedFlyout(element);
}
}
My problem is that if Button 1's flyout is open, the next tap on the screen closes the flyout. This is fine, but if the next tap happens to be on Button 2, I want the button's tap event to be fired and open its flyout. Instead, the button doesn't register a tap at all and closes Button 1's flyout.
This results in needing to tap two times - one to dismiss the Button 1's flyout, and a second to show Button 2's flyout.
In other words:
Current Flow:
Tap Button 1
Button 1's Flyout is opened
Tap Button 2
Button 1's flyout is closed, (Button 2, nor Page registers the tap)
Tap Button 2
Now Button 2's flyout is opened
What I'm Looking For:
Tap Button 1
Button 1's Flyout is opened
Tap Button 2
Button 1's flyout is closed, Button 2's flyout opens.
How can I do this? I've tried intercepting the Tapped event for the page, but when the flyout is open, it seems to intercept the Tapped event so it can be used for the Flyout's light dismissal
Would overriding the style of the Flyout, or the FlyoutPresenterStyle help me here? Or perhaps opening the Flyout in a more MVVM-ish way which would allow me for finer control on how the Flyout is opened/closed?
I'm not sure how to get around this!

Here is something I found on Microsoft documents:
When dismissing with a tap, this gesture is typically absorbed and not passed on to the UI underneath. For example, if there’s a button visible behind an open flyout, the user’s first tap dismisses the flyout but does not activate this button. Pressing the button requires a second tap.
You can change this behaviour by designating the button as an input pass-through element for the flyout. The flyout will close as a result of the light dismiss actions described above and will also pass the tap event to its designated OverlayInputPassThroughElement. Consider adopting this behaviour to speed up user interactions on functionally similar items. If your app has a favourites collection and each item in the collection includes an attached flyout, it's reasonable to expect that users may want to interact with multiple flyouts in rapid succession.
[!NOTE] Be careful not to designate an overlay input pass-through element which results in a destructive action. Users have become habituated to discreet light dismiss actions which do not activate primary UI. Close, Delete or similarly destructive buttons should not activate on light dismiss to avoid the unexpected and disruptive behaviour.
In the following example, all three buttons inside FavoritesBar will be activated on the first tap.
<Page>
<Page.Resources>
<Flyout x:Name="TravelFlyout" x:Key="TravelFlyout"
OverlayInputPassThroughElement="{x:Bind FavoritesBar}">
<StackPanel>
<HyperlinkButton Content="Washington Trails Association"/>
<HyperlinkButton Content="Washington Cascades - Go Northwest! A Travel Guide"/>
</StackPanel>
</Flyout>
</Page.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel x:Name="FavoritesBar" Orientation="Horizontal">
<HyperlinkButton x:Name="PageLinkBtn">Bing</HyperlinkButton>
<Button x:Name="Folder1" Content="Travel" Flyout="{StaticResource TravelFlyout}"/>
<Button x:Name="Folder2" Content="Entertainment" Click="Folder2_Click"/>
</StackPanel>
<ScrollViewer Grid.Row="1">
<WebView x:Name="WebContent"/>
</ScrollViewer>
</Grid>
private void Folder2_Click(object sender, RoutedEventArgs e){
Flyout flyout = new Flyout();
flyout.OverlayInputPassThroughElement = FavoritesBar;
flyout.ShowAt(sender as FrameworkElement);}

How to determine which child element of a ListView Item was clicked?

I'm developing a windows phone 8.1 app in XAML and C#. I have a ListView getting its Items from a bound list and displaying them through a DataTemplate. Now, in this DataTemplate there are multiple child elements, and when the user taps on an item in the list, I want to be able to determine what child element he actually touched. Depending on that, the app should either expand a view with more details inside the Item, or navigate to another page.
The ItemClick event handler of the ListView is ListView_ItemClick(object sender, ItemClickEventArgs e), and I thought e.OriginalSource would maybe give me the answer, but this just gave me the clicked ListItem.
I have yet to try if encapsulating the children with buttons and intercepting their click events would work, but I'm happy to try any alternative there might be for this.

I just found the solution myself. I set the ListView to SelectionMode="None" and IsItemClickEnabled="False", and then I added Tapped handlers for the individual child elements. Works just as I wanted.

I've got a TextBlock and an Image in one ListViewItem and have just used the Image_PointerPressed event. Doing that also fires the ItemClick event for the ListView so I disable it first, do the stuff I want, then re-enable the ItemClick event so that still fires when the TextBlock is pressed.
Code behind:
private async void imgDone_PointerPressed(object sender, PointerRoutedEventArgs e)
{
// disable click event so it won't fire as well
lvwCouncils.IsItemClickEnabled = false;
// do stuff
MessageDialog m = new MessageDialog("User Details");
await m.ShowAsync();
// Re-enable the click event
lvwCouncils.IsItemClickEnabled = true;
}
Xaml:
<ListView x:Name="lvwCouncils" ItemClick="lvwCouncils_ItemClicked" IsItemClickEnabled="true" >
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock
Grid.Column="1"
Text="{Binding council_name}"
FontSize="24"
Margin="10,10,30,10"
/>
<Border Height="20" Width="20" Margin="10,10,0,10" >
<Image x:Name="imgDone"
Source="Assets/user_earth.png" Stretch="UniformToFill" PointerPressed="imgDone_PointerPressed"/>
</Border>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>

Use the SelectionChanged event.
Cast the sender object to ListView type and then retrieve the item from the SelectedItem property.
Similar question here but for a different control :
Get the index of the selected item in longlistselector

TabControl- preventing user from changing the selected tab: MessageBox causing bug

I've been pounding away at this issue for a little while, and have only found part of the solution.
I'm trying to set up a TabControl so that I can in some cases prevent the user from changing the currently selected tab. When the user is prevented from changing the currently selected tab, then they are shown a dialog box.
I have already read the following documents:
WPF - reset ListBox scroll position when ItemsSource changes
http://wizardsofsmart.net/uncategorized/itemssourcechanged-event-using-attached-dependency-properties/
http://joshsmithonwpf.wordpress.com/2009/09/04/how-to-prevent-a-tabitem-from-being-selected/
http://social.expression.microsoft.com/Forums/en-US/wpf/thread/f7b46018-1e97-4bbe-ada8-49b75dbc1da2/
I have implemented the solution indicated in the 3rd link (though all of the above create the same error seen below). And it works, but...
Things mess up thoroughly if the user does the following:
attempts to change the tab when such an action is disallowed. The MessageBox pops up with the error.
the user clicks "OK" and is returned to the original window.
the user tries again to change the tab. No MessageBox appears.
if the user minimizes the window, and then maximizes it again, then the MessageBox that was supposed to appear earlier appears.
the user clicks "OK" and is returned to the original window... but the tab has been changed to the one they selected before, even though they should not be able to change tabs.
This is obviously not ideal behavior. Why isn't the MessageBox appearing the second time, and why is the tab changing when it should be disallowed from doing so?
If I remove the MessageBox part, it works fine.
Here is the code for the TabControl.SelectionChanged event handler:
bool _isChanging = false;
private void tabControlForNavigation_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (!_isChanging && canChangeTabs.IsChecked.HasValue)
{
_isChanging = true;
bool canLeave = canChangeTabs.IsChecked.Value; //normally this would be replaced by a check in the ViewModel
if (!canLeave)
{
int prevIndex = tabControlForNavigation.Items.IndexOf(tabControlForNavigation.SelectedContent);
tabControlForNavigation.SelectedIndex = prevIndex;
MessageBox.Show("Can't change tabs!"); //if I comment out this line, everything works fine.
}
_isChanging = false;
}
}
I am using MVVM to implement this. The Window looks like this:
<Window x:Class="TestTabControlSwitching.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Height="350"
Width="525">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition />
</Grid.RowDefinitions>
<CheckBox x:Name="canChangeTabs"
Content="Can Change Tabs"
IsChecked="True" />
<TabControl x:Name="tabControlForNavigation"
Grid.Row="1"
IsSynchronizedWithCurrentItem="True"
ItemsSource="{Binding Collection}"
SelectedItem="{Binding SelectedItem}"
SelectionChanged="tabControlForNavigation_SelectionChanged"
Margin="4"
HorizontalAlignment="Stretch">
<TabControl.ItemTemplate>
<DataTemplate>
<ContentPresenter Content="{Binding Path=Name}" />
</DataTemplate>
</TabControl.ItemTemplate>
</TabControl>
</Grid>
I'm omitting the rest of the code for sake of brevity- there is a pretty straight-forward ViewModel structure backing the window.

As you noticed, the problem is the MessageBox inside the event handler. The focus will change to the MessageBox and you can get all kind of undesired effects. I've had my own problems with this.
Here is a couple of SO question on the same subject
WPF: Does MessageBox Break PreviewMouseDown?
Wpf stop routing event when MessageBox appear?
If you must display a message to the user then an alternate approach might be to create a new Window which you style like a MessageBox and then call Show (not ShowDialog) on it inside the event handler.

I know this post is a bit old, but I have a very easy way to accomplish this:
Use the tab_Enter event and create a method that performs your check and displays a MessageBox to the user and then set myTabs.SelectedIndex to the prior index. A simple example:
private void someTab_Enter(object sender, EventArgs e)
{
if (myCondition)
{
MessageBox.Show("Sorry, myCondition will not let you move to this tab.");
myTabs.SelectedIndex = someOtherTabIndex;
}
}

This was a very detailed question. I had the same problem you had (i.e. the message box doesn't display on 2nd or 3rd selection changed until you minimize and maximize the window) and after much debugging and multiple google searches, stumbled on the below linked MSDN forum post.
[TabControl SelectionChanged Strange Behaviour?]
Please ignore the poorly formatted question and answer. But as mentioned in the answer, putting it inside a dispatcher and focussing the selected tab after setting the index resolved the issue for me.

You are missing an easy trick. Just make focusable=False for the Tab header.
<TabItem Header="MY TAB" Focusable="False">
You could bind this property to your view model.
<TabItem Header="MY TAB" Focusable="{Binding Bool_CanHasCheeseBurger}">

In Silverlight, how to bind ListBox item selection to a Navigate event?

I am writing a windows-phone 7 application. I've got a page with a list of TextBlock(s) contained in a ListBox. The behavior I want is that upon clicking one of those TextBlock(s) the page is redirected to a different one, passing the Text of that TextBlock as an argument.
This is the xaml code: (here I am binding to a collection of strings, and the event MouseLeftButtonDown is attached to each TextBlock).
<ListBox x:Name="List1" ItemsSource="{Binding}">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock MouseLeftButtonDown="List1_MouseLeftButtonDown" Text="{Binding}"
FontSize="20"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
But this has been unsuccessful for me. I have tried attaching MouseLeftButtonDown event to either the individual TextBox(es) or to the ListBox. And I have had exceptions raised as soon as I use NavigationService.Navigate(uri). Which event should be attached? Should the event be attached to the individual items or to the list as a whole?
I have found a way to work around this problem by populating ListBox with HyperlinkButton(s). However, I would like to understand why the TextBox approach did not work.
This is my first attempt with Silverlight, so I might be missing something basic here.

There are a few ways to do this but I'll walk you through one of the the simplest (but not the purest from an architectural perspective).
Basically you want to find out when the selection of the ListBox changes. The ListBox raises a SelectionChanged event which can be listened to in the code behind.
<ListBox x:Name="List1" ItemsSource="{Binding}" SelectionChanged="SelectionChangedHandler" SelectionMode="Single" >
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}" FontSize="20"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Then have a handler something like:
private void SelectionChangedHandler(object sender, SelectionChangedEventArgs e)
{
IList selectedItems = e.AddedItems;
string val = selectedItems.OfType<string>().FirstOrDefault();
NavigationService.Navigate(new Uri(val));
}
One thing you'll need to be aware of is that ListBoxes support multiple selection. For this reason, the event arguments give you back a list of the selected items. For simplicity, all I've done is taken the first value from this list and used that as the navigation value. Notice how I've also set the SlectionMode property of the ListBox to Single which will ensure the user can only select one item.
If I were doing this for real I'd look into creating an TriggerAction tat can be hooked up to an event trigger through xaml which will remove the for code behinds. Take a look at this link if you're interesetd.

In addition to Chris' and James' replies, I'd add that you will also need to clear the listbox selection in the event handler, otherwise the user won't be able to tap the same item twice on the listbox (because the item will already be selected).
Using James' approach, I would change the SelectionChangedHandler() implementation as follows:
private void SelectionChangedHandler(object sender, SelectionChangedEventArgs e)
{
// Avoid entering an infinite loop
if (e.AddedItems.Count == 0)
{
return;
}
IList selectedItems = e.AddedItems;
string val = selectedItems.OfType<string>().FirstOrDefault();
NavigationService.Navigate(new Uri(val));
// Clear the listbox selection
((ListBox)sender).SelectedItem = null;
}

What I would recommend is binding the SelectedItem property of the ListBox to a property in your ViewModel. Then, on the ListBox's SelectedItemChanged event, navigate to to the appropriate URL passing the data key on the QueryString, or upgrade to something like MVVM Light and put the actual SelectedItem object on the message bus for the child window to pick up. I have a sample of this second method on my Skydrive that you can check out.
HTH!
Chris

Right-click on a Listbox in a Silverlight 4 app

I am trying to implement what I used to take for granted in Winforms applications. I am a Silverlight noob, so hopefully all this is elementary.
I have a listbox in a Silverlight 4 app. I'd like to do the following:
Right-click on the listbox
Have the item under the location where I click highlight itself
I'd like a context menu to popup (with my own items in the context menu)
From my research so far, it appears that there is no ContextMenu construct in Silverlight, instead we have to build up a Grid/Canvas structure and attach it to a Popup object, which is what is then popped up.
My questions are as follows:
To accomplish #2, I need some kind of hit test on the listbox. I can't figure out how to do that and my google-fu isn't helping.
Once I do identify the index under the mouse, how do I actually select the item?
Is there a reusable Context menu component somewhere that I can use? Extra credit if the component allows arbitrary sub-menus.

I've been looking around for the same thing. I checked the Silverlight Control Toolkit at CodePlex and went through the samples (it's a very handy resource) and here's what I found to be the solution to what you asked:
Create an ItemTemplate for your ListBox
in the part that you want to be "right-clickable" of your ItemTemplate set the attached property ContextMenuService.ContextMenu that exists within the System.Windows.Controls.Input.Toolkit namespace
add MenuItem controls to your ContextMenu and set the Click property to the corresponding click event handler
in the event handler, get the DataContext from the sender (you can use that to find the corresponding element in the ListBox)
to make that element Selected, just set the SelectedItem property in the list box to it
Add any custom logic to the event handler
There's an example in the samples page, just go to "Input->ContextMenu" from the navigation pane.
If you want something concise, Here's a simplified example:
<ListBox ItemsSource="{StaticResource People}"
Name="myListBox">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}">
<controlsInputToolkit:ContextMenuService.ContextMenu>
<controlsInputToolkit:ContextMenu>
<controlsInputToolkit:MenuItem Header="Show in MessageBox"
Click="show_Click" />
</controlsInputToolkit:ContextMenu>
</controlsInputToolkit:ContextMenuService.ContextMenu>
</TextBlock>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
with:
xmlns:controlsInputToolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit"
for the code:
private void show_Click(object sender, RoutedEventArgs e)
{
var person = ((MenuItem)sender).DataContext as Person;
if (null == person) return;
MessageBox.Show("My Name is: " + person.Name);
myListBox.SelectedItem = person;
}
I hope this helps :)

There's the MouseRightButtonDown event. If you bind that on the ListBox:
<ListBox Height="143" Name="listBox1" Width="218"
MouseRightButtonDown="listBox1_MouseRightButtonDown" />
you'll get what you need. The code behind is:
private void listBox1_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
}
The MouseButtonEventArgs will give you the position via the GetPosition method.