Element inside Flyout in XAML isn't accessible from Code Behind - c#

I'm working on a UWP application and need some help with Flyout. I have a Flyout in my XAML with a few TextBlock elements but don't seem to be able to call those elements in the Code Behind. Everytime I try that, I get an Exception "The name TB does not exist in the current context."
I already searched for possible solutions and tried the following things: Made a clean build, Restarted VS 2017, Cleared the bin folder manually and then tried to rebuild
But nothing seems to work and I'm on a point where I don't know what to do.
<Page
x:Class="FuhrparkUWP.Pages.Parkhaeuser"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:converter="using:FuhrparkUWP.Converter"
xmlns:data="using:FuhrparkStructureUWP.Model"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Page.Resources>
<converter:PassendFuerToStringConverter x:Key="PassendFuerToStringConverterKey"></converter:PassendFuerToStringConverter>
<converter:BelegtStatusToImageConverter x:Key="BelegtStatusToImageConverterKey"></converter:BelegtStatusToImageConverter>
</Page.Resources>
<Grid>
<ComboBox Name="CmbSelectParkhaus" Header="Parkhaus" HorizontalAlignment="Center" VerticalAlignment="Top" Width="200" SelectionChanged="CmbSelectParkhaus_SelectionChanged"/>
<GridView ItemsSource="{x:Bind Parkplaetze}" Name="ContentGrid" HorizontalAlignment="Center" VerticalAlignment="Top" Margin="0, 100, 0, 0">
<GridView.ItemTemplate>
<DataTemplate x:Name="ImageTextDataTemplate" x:DataType="data:Parkplatz">
<StackPanel Height="280" Width="180" Margin="12" Tapped="Content_Tapped">
<Image Source="{Binding Path=IstBelegt, Converter={StaticResource BelegtStatusToImageConverterKey}}" Height="180" Width="180" Stretch="UniformToFill"/>
<StackPanel Margin="0,12">
<TextBlock Text="{x:Bind FahrzeugKennzeichen}"/>
<TextBlock Text="{Binding Path=PassendFuer, Converter={StaticResource PassendFuerToStringConverterKey}}" Style="{ThemeResource CaptionTextBlockStyle}" Foreground="{ThemeResource SystemControlPageTextBaseMediumBrush}"/>
</StackPanel>
<FlyoutBase.AttachedFlyout>
<Flyout>
<StackPanel>
<Image Source="/Assets/Images/ParkplatzFrei.png" Width="180" Height="180"></Image>
<TextBlock Name="TB"></TextBlock>
<TextBlock Text="Passend für: LKW, PKW, Motorrad"></TextBlock>
<TextBlock Text="Belegt durch: FREI"></TextBlock>
</StackPanel>
</Flyout>
</FlyoutBase.AttachedFlyout>
</StackPanel>
</DataTemplate>
</GridView.ItemTemplate>
</GridView>
</Grid>
</Page>
I expect to call TB.Text = "xyz" for example from the Code Behind page, but at the moment I'm not able to call it.
I'm still able to call the other elements outside from the Flyout like "CmbSelectParkhaus" though.

You cannot handle things inside a DataTamplate, datamplates are not actual ui entities, they are Templates.
Assuming you want to achieve the same kind of access across all of your GridView items, you have to attach dependency properties, and either create programmatic binds on the PrepareContainerForItemOverride or the appropriate xaml "{Binding}" expressions.
This just opens whole new rabbit hole, especially if you are unaware of at least a single thing i mentioned so far, but you can just look up the bolded words one by one.

Related

HeaderedContentControl header template not being used

I'm fairly new to WPF and am working with some legacy code, not sure how to use the HeaderedContentControl Header. I'd like to put in a StackPanel and customize the look of a header, just not sure how to do that.
Could someone give me some guidance on what to do next?
I have this xaml and the HeaderTemplate is never used.
<UserControl x:Class="PEC.Admin.WindowsControls.Program.Views.ProgramProductEnrichmentColorsView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:commonControls="clr-namespace:ManagerConsole.Common.Controls;assembly=ManagerConsole.Common.Controls"
xmlns:program="clr-namespace:PEC.Admin.ViewModel.Program;assembly=PEC.Admin.ViewModel.Program"
mc:Ignorable="d"
d:DesignWidth="300"
d:DataContext="{d:DesignInstance program:ProgramProductEnrichmentColorsViewModel}">
<commonControls:ExpanderPanel IsExpanded="{Binding Path=IsExpanded,Mode=TwoWay}">
<HeaderedContentControl.HeaderTemplate> <!-- this never gets used... -->
<DataTemplate>
<StackPanel>
<Label Content="{Binding Path=Header}"></Label>
</StackPanel>
</DataTemplate>
</HeaderedContentControl.HeaderTemplate>
<StackPanel HorizontalAlignment="Stretch"
VerticalAlignment="Top"
Width="Auto"
Margin="3"
Background="White">
<TextBlock Text="Source Type:"
Margin="0,5,0,0" />
<TextBox IsReadOnly="True"
IsTabStop="False"
Background="LightGray"
BorderThickness="0"
Text="{Binding Path=SourceTypeName, Mode=OneTime}" />
</StackPanel>
</commonControls:ExpanderPanel>
</UserControl>
HeaderTemplate is applied. To verify it - set a background to the Label in HeaderTemplate.
HeaderTemplate doesn't display anything though, because binding is incorrect. Template is applied to the data set in Header property, which currently has null value.
So change code as in the example below (I tried with Expander, hopefully it will work for custom commonControls:ExpanderPanel):
<Expander IsExpanded="{Binding Path=IsExpanded, Mode=TwoWay}"
Header="{Binding ComplexObject}">
<HeaderedContentControl.HeaderTemplate>
<DataTemplate>
<StackPanel>
<Label Background="Green" Content="{Binding PropertyOfTheObject}"/>
</StackPanel>
</DataTemplate>
</HeaderedContentControl.HeaderTemplate>
</Expander>
Header is a dependency property and can be set via Binding. Header becomes a source for bindings in a HeaderTemplate. Or it can be some constant (Header="Click to expand"), resource (Header="{StaticResource ExpandTitle}") or complex content, e.g.:
<Expander.Header>
<TextBlock Text="Click to expand"/>
</Expander.Header>

How to add AppTitle to NavigationView

Is installed the Fall update and tried out the Navigation View control. Seems close enough to the Hamburger control from the UWP toolkit.
But i am having trouble adding a custom app title to the page. The directions in the article are kinda unclear to me:
Drawing into the title bar has the side-effect of hiding your app's title. To help users, restore the title by adding your own TextBlock. Add the following markup to the root page containing your NavigationView.
This is followed by this xaml:
<!-- Page attribute -->
xmlns:appmodel="using:Windows.ApplicationModel"
<TextBlock x:Name="AppTitle" Style="{StaticResource CaptionTextBlockStyle}" Text="{x:Bind appmodel:Package.Current.DisplayName}" IsHitTestVisible="False"/>
So i thought i'd drop this XAML code inside my Pages grid, but i don't get an App Title. Where do i need to drop this code to make it work?
Heres my page xaml
<Page
x:Class="MyPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:appmodel="using:Windows.ApplicationModel"
mc:Ignorable="d">
<Grid>
<TextBlock x:Name="AppTitle" Style="{StaticResource CaptionTextBlockStyle}" Text="{x:Bind appmodel:Package.Current.DisplayName}" IsHitTestVisible="False"/>
<NavigationView>
<Frame x:Name="ContentFrame" Margin="24">
<ContentControl />
</Frame>
</NavigationView>
</Grid>
</Page>
Your TextBlock is hidden behind your NavigationView. This is more obvious if you have a long enough title that it extends past the Nav Pane:
You can put it on top by switching the order in Xaml:
<Grid>
<NavigationView>
<Frame x:Name="ContentFrame" Margin="24">
<ContentControl />
</Frame>
</NavigationView>
<TextBlock x:Name="AppTitle" Style="{StaticResource CaptionTextBlockStyle}" Text="{x:Bind appmodel:Package.Current.DisplayName}" IsHitTestVisible="False"/>
</Grid>

Responsive Windows App Element

Is there any XAML element that will automatically wrap to a new line for sub elements that don't have enough room on a line?
What I mean is that on a wide screen I'll get:
Box1 Box2 Box3
And on a narrow one:
Box1 Box2
Box3
Without having to listen to events and fix it by code.
The comments mention VariableSizedWrapGrid as a solution. But I can't figure out how to make it wrap.
You can use a simple GridView to do it. If you don't set a Height, it should work like a charm.
<GridView Name="xConcerts" ItemsSource="{x:Bind Artist.UpcomingEvents, Mode=OneWay}">
<GridView.ItemTemplate>
<DataTemplate x:DataType="songkick:EventExt">
<Border CornerRadius="8" Background="{ThemeResource ThemeGrayHighColorBrush}" Opacity="0.8">
<StackPanel Margin="18,2">
<TextBlock Text="{x:Bind FullDisplayDate, Converter={StaticResource FormatStringToDateDayConverter}}" Style="{ThemeResource ThemeDateBoldStyle}"/>
<TextBlock Text="{x:Bind FullDisplayDate, Converter={StaticResource FormatStringToDateMonthConverter}}" Style="{ThemeResource ThemeDateBoldStyle}" Margin="0,-4,0,0"/>
</StackPanel>
</Border>
</DataTemplate>
</GridView.ItemTemplate>
<GridView.ItemContainerTransitions>
<TransitionCollection>
<RepositionThemeTransition/>
</TransitionCollection>
</GridView.ItemContainerTransitions>
</GridView>
According to your requirement, using the WrapPanel control in WinRTXamlToolkit will meet your needs.
Sample code here:
<Page x:Class="TestDemo.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Tool="using:WinRTXamlToolkit.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="using:TestDemo"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Tool:WrapPanel>
<Button Width="200" Margin="10">1</Button>
<Button Width="200" Margin="10">2</Button>
<Button Width="200" Margin="10">3</Button>
</Tool:WrapPanel>
</Page>
And the output here:

Custom ListView from inside HubAppSection -- Windows Phone 8.1

I am currently building a Windows Phone Applicaation, based off of the HubAppTemplate.
The template comes with a sample .JSON data source that it uses to populate the data of each HubSection. However, I want to use a non JSON type of data as the basis of my code. Inside my C# code, I need to make a function call to my backend to get the type of data I want out of it.
I can put this data inside of my own custom list (on the C# side), but how can I make that list act as the data source for my HubSection? Any old listview/list box works perfectly. Basically, I need help wiring the C# to the XAML -- the main issue is that I cannot access my listView inside of the datatemplate by name.
Can anyone give me some pointers to get going in the right direction?
Here is some reference code to show you what I am talking about:
<HubSection x:Uid="Clubs" Header="Clubs" DataContext="{Binding Groups}" HeaderTemplate="{ThemeResource HubSectionHeaderTemplate}">
<DataTemplate>
<ListView Name="ClubsList"
IsItemClickEnabled="True"
ItemsSource="{Binding}"
ItemClick="GroupSection_ItemClick"
ContinuumNavigationTransitionInfo.ExitElementContainer="True">
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Margin="0,0,0,27.5">
<TextBlock Text="{Binding Title}" Style="{ThemeResource ListViewItemTextBlockStyle}" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</DataTemplate>
</HubSection>
The above XAML is basically pulled straight from the hubapp template. I want to be able to use my own itemssource inside of that ListView that is generated from my C# code -- however, I cannot figure out how this ItemsSource works. I also cannot access my listview by name (ClubsList).
Here is the initialization code going on up top (wasn't sure if it was important to post this or not):
<Page
x:Class="HubAppTemplate.HubPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:HubAppTemplate"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:data="using:HubAppTemplate.Data"
DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"
d:DataContext="{Binding Source={d:DesignData Source=/DataModel/SampleData.json, Type=data:SampleDataSource}}"
mc:Ignorable="d">
<Page.Resources>
<DataTemplate x:Key="HubSectionHeaderTemplate">
<TextBlock Margin="0,0,0,-9.5" Text="{Binding}"/>
</DataTemplate>
<!-- Grid-appropriate item template as seen in section 2 -->
<DataTemplate x:Key="Standard200x180TileItemTemplate">
<Grid Margin="0,0,9.5,9.5" Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}">
<Image Source="{Binding ImagePath}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}" Height="138.5" Width="138.5"/>
<TextBlock Text="{Binding Title}" VerticalAlignment="Bottom" Margin="9.5,0,0,6.5" Style="{ThemeResource BaseTextBlockStyle}"/>
</Grid>
</DataTemplate>
<DataTemplate x:Key="StandardTripleLineItemTemplate">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}" Margin="0,9.5,0,0" Grid.Column="0" HorizontalAlignment="Left">
<Image Source="{Binding ImagePath}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}" Height="79" Width="79"/>
</Border>
<StackPanel Grid.Column="1" Margin="14.5,0,0,0">
<TextBlock Text="{Binding Title}" Style="{ThemeResource ListViewItemTextBlockStyle}"/>
<TextBlock Text="{Binding Description}" Style="{ThemeResource ListViewItemContentTextBlockStyle}" Foreground="{ThemeResource PhoneMidBrush}" />
<TextBlock Text="{Binding Subtitle}" Style="{ThemeResource ListViewItemSubheaderTextBlockStyle}" />
</StackPanel>
</Grid>
</DataTemplate>
<DataTemplate x:Key="StandardDoubleLineItemTemplate">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}" Margin="0,9.5,0,0" Grid.Column="0" HorizontalAlignment="Left">
<Image Source="{Binding ImagePath}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}" Height="79" Width="79"/>
</Border>
<StackPanel Grid.Column="1" Margin="14.5,0,0,0">
<TextBlock Text="{Binding Title}" Style="{ThemeResource ListViewItemTextBlockStyle}"/>
<TextBlock Text="{Binding Subtitle}" Style="{ThemeResource ListViewItemSubheaderTextBlockStyle}"/>
</StackPanel>
</Grid>
</DataTemplate>
</Page.Resources>
<Grid x:Name="LayoutRoot">
<Hub x:Name="Hub" x:Uid="Hub" Header="Club Alert" Background="{ThemeResource HubBackgroundImageBrush}">
It is pulling from the JSON backend, but I want to just use my own custom listview for each section. Deleting the DataSource and data template headers gives me errors, however.
Thank you so much for your help in advance!
--A total newbie
HubSection elements require their contents to be populated via a template, so you can't just remove the <DataTemplate> tags, unfortunately. However, there is a simple way to accomplish what you are trying to do, if I understand you correctly.
If you're starting with the default Hub template, you should have this function in your HubPage.xaml.cs file
private async void NavigationHelper_LoadState(object sender, LoadStateEventArgs e)
{
// TODO: Create an appropriate data model for your problem domain to replace the sample data
var sampleDataGroups = await SampleDataSource.GetGroupsAsync();
this.DefaultViewModel["Groups"] = sampleDataGroups;
MainViewModel viewModel = DataContext as MainViewModel;
if (!viewModel.IsDataLoaded)
{
viewModel.Load();
}
}
this.DefaultViewModel is just a Dictionary, and they have loaded the sample JSON into a variable and stored this in the ["Groups"] key of the dictionary. Since the Page's DataContext is being bound to {Binding DefaultViewModel, RelativeSource={RelativeSource Self}}, the HubSection's DataContext is being bound to {Binding Groups}, and the ItemsSource of the ListView in each DataTemplate is being bound to {Binding}, each element of the loaded JSON is being used to fill the items of the ListView.
A simple solution would be to assign this.DefaultViewModel["Groups"] to the C# List you are creating from the data you load from your back end.
Something like this:
private async void NavigationHelper_LoadState(object sender, LoadStateEventArgs e)
{
// TODO: Create an appropriate data model for your problem domain to replace the sample data
var myData = await GetListOfThingsFromBackend();
this.DefaultViewModel["Groups"] = myData;
MainViewModel viewModel = DataContext as MainViewModel;
if (!viewModel.IsDataLoaded)
{
viewModel.Load();
}
}
A better approach would probably be to separate out all ViewModel functionality to it's own class that is better suited to your needs, and then adjust the various DataContext properties throughout the XAML, but that would likely take more time. I can elaborate if needed, but the simple solution is probably enough for now.

How to adapt the app to multiple resolution in Windows8

I have the layout code below in xaml
<Grid>
<StackPanel x:Name="TestStackPanel" Grid.Row="2" Orientation="Horizontal">
<ScrollViewer x:Name="TestScrollViewer" Height="300" VerticalScrollBarVisibility="Auto">
<GridView x:Name="TestGridView"
Width="940"
Background="{StaticResource ApplicationPageBackgroundThemeBrush}"
ItemTemplate="{StaticResource TestTemplate}"
ItemsPanel="{StaticResource TestItemPanelTemplate}"
ItemContainerStyle="{StaticResource TestItemStyle}"
SelectionMode="None"
HorizontalAlignment="Left"/>
</ScrollViewer>
<Button x:Name="TestButton" Content="ClickMe" VerticalAlignment="Bottom" Margin="10,5,0,0" Click="TestButton_Click"/>
</StackPanel>
</Grid>
This displays well in 1366*768 resolution, but if I change the resolution to 2560*1400, it couldn't displays as expected, I know it's certain, but how to adpat the layout to different resolutions? I have tried to add a ViewBox to encapsulate the Grid, it works well in FullScreenLandScape view, but when I change the app to Snap view, the Grid displays in a samll space.
Anyone can help?
Register to the LayoutUpdated event at the UI element.
And re-calculate the layout according to Window.Current.Bounds.Width.

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