Develop Reference

Back button not working in XAML / W8

I have the following button on my page:
<AppBarButton Grid.Column="0" x:Name="backButton" Icon="Back" Margin="10,26,0,-1"
Command="{Binding NavigationHelper.GoBackCommand, ElementName=pageRoot}"
IsEnabled="True"
Visibility="Visible"
Foreground="Green"
AutomationProperties.Name="Back"
AutomationProperties.AutomationId="BackButton"
AutomationProperties.ItemType="Navigation Button" Grid.Row="1" Grid.RowSpan="2" VerticalAlignment="Stretch"
/>
The button appears but clicking it does nothing. This was placed on the second of two pages in the application. I followed the instructions in NavigatonHelper.cs to get it wired up to my second page, but haven't done anything special in the first. What am I missing?
I even tried tying the Click property to a custom function:
public void ClickGoBack(object sender, RoutedEventArgs routedEventArgs) {
this.Frame.Navigate(typeof(HubPage));
}
But this never even got hit when I clicked the button.

Have you checked the Click existed in AppBarButton defined?
like: <AppBarButton ... Click="ClickGoBack"></AppBarButton>
and you should use
if (this.Frame.CanGoBack)
{
this.Frame.GoBack();
}
instead of
this.Frame.Navigate(typeof(HubPage));

You could do this instead much more easier for me.
<AppBar><Button Style="{StaticResource BackButtonStyle}" Click="Click1"></Button>
</AppBar>
and for your code behind...
private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
{
Frame.GoBack();
}

Something was put after the top grid in the XAML that overlapped the button - I didn't understand the concept of "natural order" until now. Thanks for the help everyone!

Get previous page name

something that I thought would be simple is turning out not to be, or I'm just not thinking hard enough :)
I have a page which I navigate to, in the OnNavigateTo event I set the SelectedIndex of a ListPicker and that works fine.
If I then touch the ListPicker and select a new value the OnNavigateTo event is fired again and the new value is overridden by the original value.
My initial thought was to simply check the parent page name and if it was the ListPicker then skip the initial setting but I can't seem to find where to get the parent page name from.
Any clues? or a better way I should be handling this?
Here's the XAML:
<toolkit:ListPicker x:Name="Status" Margin="10,549,163,-97" Header="Status" FullModeHeader="Status" ExpansionMode="FullScreenOnly" BorderBrush="Black" Foreground="Black" Grid.ColumnSpan="2" Visibility="Visible">
<toolkit:ListPicker.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}" />
</DataTemplate>
</toolkit:ListPicker.ItemTemplate>
<toolkit:ListPicker.FullModeItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}"
FontSize="43"
FontFamily="{StaticResource PhoneFontFamilyLight}"/>
</DataTemplate>
</toolkit:ListPicker.FullModeItemTemplate>
</toolkit:ListPicker>
And here's the Loaded event:
private void AddNote_Loaded(object sender, RoutedEventArgs e)
{
this.TicketStatus.ItemsSource = ticketStatus();
string st;
if (NavigationContext.QueryString.TryGetValue("status", out st))
{
tStatus = st;
TicketStatus.SelectedIndex = GetStatus(tStatus);
}
}

Ok, worked around it but creating my own page list and manually adding and removing the pages I want to check for. Bit of a hack but it works :)

Hold Event Longlistselector

Hej
I want to create a standard holdevent. When you hold an element, there would appear some options you could chose like a new list.
How do you create this, is it just simply done with a popup or is there a smarter way?
Extra
After finding the answer, see answer below, some nice info is:
Put the context creation inside the hold event.
Then you can change to different contextmenus depending on the item. You can get the item that was holded by the following
private void StackPanel_Hold(object sender, GestureEventArgs e)
{
ItemViewModel itemViewModel = (sender as StackPanel).DataContext as ItemViewModel;
string t = itemViewModel.LineOne;
}
And
<ListBox x:Name="MainListBox" Margin="0,0,-12,0" ItemsSource="{Binding Items}" >
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Margin="0,0,0,17" Height="78" Hold="StackPanel_Hold">
<TextBlock Text="{Binding LineOne}" />
<TextBlock Text="{Binding LineTwo}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
A good link for easy implementation is also youtube link below, replicated here :
Youtube

A ContextMenu is one option..
http://blogs.msdn.com/b/msgulfcommunity/archive/2013/05/19/windows-phone-toolkit-context-menu-getting-selected-item-within-a-long-list-selector.aspx

Silverlight: Layout changes when I call NavigationService.Navigate

This is a really weird bug. I have no idea why it could be happening. I know that posting it here is a bit of a long-shot, but I'm out of other ideas.
I have two ListBoxs that act as menus.
<ListBox Margin="56,8,15,0" FontSize="64"
ItemsSource="{Binding FavoriteSections}"
SelectionChanged="MenuList_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<toolkit:ContextMenuService.ContextMenu>
<toolkit:ContextMenu>
<toolkit:MenuItem Header="Remove" Click="FavoritesContextMenuItem_Click" />
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
<TextBlock Text="{Binding DisplayName}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<ListBox x:Name="sectionList" Margin="56,8,15,0" FontSize="64"
SelectionChanged="MenuList_SelectionChanged"
ItemsSource="{Binding SectionViewModels}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<toolkit:ContextMenuService.ContextMenu>
<toolkit:ContextMenu>
<toolkit:MenuItem Header="Add to favorites" Click="SectionContextMenuItem_Click" />
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
<TextBlock Text="{Binding DisplayName}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
The bug exists across both of them.
When the selection changes on either menu, this method is called:
void MenuList_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.AddedItems.Count == 0)
{
return;
}
Uri page = null;
object selected = e.AddedItems[0];
if (selected is NavigableItem)
{
NavigableItem selectedItem = (NavigableItem)selected;
page = selectedItem.Page;
}
else if (selected is SectionViewModel)
{
SectionViewModel selectedVM = (SectionViewModel)selected;
page = selectedVM.Section.Page;
}
Debug.Assert(page != null, "What is the type of `selected`?");
// if I comment out this line, the problem goes away:
NavigationService.Navigate(page);
ListBox selectedBox = (ListBox)sender;
selectedBox.SelectedIndex = -1;
}
If I comment out the NavigationService.Navigate() line, the problem goes away. If I replace the line with a different URI, the problem remains.
About 70% of the time, when I click on a menu item, the content jumps all over the page. (The remaining 30%, no bug occurs.) It happens too quickly to see what's really going on, but different UI elements overlap each other.
This only occurs the first time I click on something in those menus during the app's lifetime. If I hit "back" then select a menu item again, the problem will not occur.
What could be happening here? I really have no idea. The code-behind doesn't have a OnNavigatedFrom method, so I don't think it's a problem there.
I'm using Silverlight for Windows Phone 7
Update: Mysteriously, I can't seem to reproduce this in the debugger - only after deploying the app and running it in the emulator unattached. ???
Update 2: The bug appears when NavigationService.Navigate() is called from the Click event handler of a button, as well:
<Button Content="Foo" Click="Button_Click" Grid.Row="0"/>
private void Button_Click(object sender, RoutedEventArgs e)
{
NavigationService.Navigate(new Uri("/Views/sections.xaml?section=43", UriKind.Relative));
}
Looks like the bug has to do with the navigation, not the UI element used to trigger the call.
Update 3: More weirdness. Still not able to reproduce the app while the debugger is attached. If I make the loading progress bar always collapsed, the bug disappears:
<ProgressBar x:Name="LoadingProgressBar"
IsIndeterminate="True"
Visibility="Collapsed"
Style="{StaticResource PerformanceProgressBar}"
VerticalAlignment="Top"/>
Alternatively, commenting out this line in code-behind makes the bug disappear:
LoadingProgressBar.Visibility = Visibility.Collapsed;
I really don't understand what's going on here. That line of code is not executed when the page is navigated from.
Here is the full XAML of the control that's getting messed up:
<ProgressBar x:Name="LoadingProgressBar"
IsIndeterminate="True"
Visibility="Collapsed"
Style="{StaticResource PerformanceProgressBar}"
VerticalAlignment="Top"/>
<TextBlock x:Name="DownloadFailed"
Visibility="Collapsed"
Style="{StaticResource disabledText}"
Margin="56,8,8,-8" >
FooBar.com could not be reached. Do you have a network connection?
</TextBlock>
<ListBox x:Name="sectionList" Margin="56,8,15,0" FontSize="64"
SelectionChanged="MenuList_SelectionChanged"
ItemsSource="{Binding SectionViewModels}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<toolkit:ContextMenuService.ContextMenu>
<toolkit:ContextMenu>
<toolkit:MenuItem Header="Add to favorites" Click="SectionContextMenuItem_Click" />
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
<TextBlock Text="{Binding DisplayName}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</controls:PivotItem>

The problem lies in your usage of the Indeterminate ProgressBar. All its animations are done on the UI thread, and not the Compositor thread, as is the usual practise. Since you are already using the Windows Phone Toolkit, you can easily replace your ProgressBar with the PerformanceProgressBar offered by the toolkit. This should solve your problems.

Before I begin, let me say that I don't have a lot of experience with Windows Phone, so my answers are based on more generic WPF knowledge, so forgive me if I'm overlooking specifics of the platform, or am referencing features not available.
Some diagnostic questions (sorry this isn't a direct answer):
Firstly, it does seem like Navigate is calling a lot of layoutUpdates. I haven't yet seen what type of container is containing the pages you're updating, but it is worth asking, is that also being disrupted or only the menus?
Secondly, could you try specifying your itemPanel explicitly? You're expecting them to be virtualizingStackPanels, but you may find that some parent object in your visual hierarchy is creating a different inheritance scenario.
You have these in a grid, which is meant to size to its content, or take the default size (100x100 in normal WPF) or take sizing from its parent, which without knowing how you've specified the grid, or the grid's parent, it's difficult to know its behaviour. Furthermore, Grids automatically z-order their children according to the order in which they were added. Can you determine whether it is just the layout of the lisboxes that is being disturbed, or whether it is the entire grid? Or, is it larger than that?
If you attach to the layoutUpdated() event of the listboxes, grid, or grid's parent, you should be able to look at the stacktraces that lead you there - it sounds to me that you'll find that layoutUpdated() is firing more than you'd like it to. Further, you'll be able to output the heights and widths (ActualHeight etcetera of course) during those steps so that you can see when exactly those changes happen.
I hope that some of these diagnostic steps might help you reach an answer.

Why is my Button event is not occuring?

I am having an issue with my button event not occuring
Basically I have cart items that are listed in the listbox. When the delete button is clicked then the item is deleted from the list box.
I tried debugging, but it seems to not even call the method for when the button is clicked.
In my ticketscreen.xaml file I specify my button in the template:
<DataTemplate x:Key="TicketTemplate">
<StackPanel Orientation="Horizontal" HorizontalAlignment="Left" Height="50">
...
<Button Name="Remove" Width="35" Height="35"
FontFamily="Resources/#charlemagnestd-regular.otf" FontSize="24"
Click="removeCartItem" Grid.Column="5"
MouseMove="Remove_MouseMove">X</Button>
...
</StackPanel>
</DataTemplate>
My List box is the following:
<ListBox Name="TicketItems" ItemsSource="{Binding}"
ItemTemplate="{StaticResource TicketTemplate}"
Grid.Row="3" Grid.ColumnSpan="6" Background="Transparent"
BorderBrush="Transparent" IsHitTestVisible="False">
</ListBox>
My method removeCartItem is in the ticketscreen.xaml.cs:
private void removeCartItem(object sender, RoutedEventArgs e)
{
Console.WriteLine("TestingCartRemove");
}
Am I missing something obvious?
Thx in adv! :)
Edit:
There seems to be something infront of it... maybe the listbox? How do I make it so that I am not clicking the ListBox, but I can click on things within the Stackpanel, which are contents of the list box.

IsHitTestVisible="False" for the ListBox is disabling the click event for the Button. It makes all content within the ListBox invisible to hit-test as well.

Are you sure is not firing? Maybe you haven't seen the output in Visual Studio Output Window. Try to call a MessageBox.Show("Test"); instead.

You have a listbox control, which leads me to believe that this is not a console application. Therefore, Console.WriteLine() will not show you anything. Try MessageBox.Show() instead.