I'm building a UWP in C# with Visual Studio, and need to hide and show a NavigationView, named 'navigationView' as required.
I am using the property .IsPaneVisible to achieve this, but am encountering a strange bug:
I can set IsPaneVisible = true or false in the xaml document, but if I set navigationView.IsPaneVisible = false; in the related C# document, and run a debug build of the app from Visual Studio, the app crashes with the error
System.ArgumentException: 'The parameter is incorrect.
Even stranger, if I run the same debug build, but launched directly, outside Visual Studio, the app functions normally without crashing at this line.
Does anyone have an idea of why this might be happening or how I could fix it?
Here's the xaml code:
<Page
x:Class="Sheet_Music_Reader.Views.ShellPage"
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:i="using:Microsoft.Xaml.Interactivity"
xmlns:behaviors="using:Sheet_Music_Reader.Behaviors"
xmlns:winui="using:Microsoft.UI.Xaml.Controls"
xmlns:helpers="using:Sheet_Music_Reader.Helpers"
xmlns:views="using:Sheet_Music_Reader.Views"
Loaded="OnLoaded"
mc:Ignorable="d">
<Page.Resources>
<!--This top margin is the height of the custom TitleBar-->
<Thickness x:Key="NavigationViewContentMargin">0,48,0,0</Thickness>
<Thickness x:Key="NavigationViewContentGridBorderThickness">0</Thickness>
<SolidColorBrush x:Key="NavigationViewContentBackground" Color="Transparent"></SolidColorBrush>
</Page.Resources>
<Grid>
<Border x:Name="AppTitleBar"
IsHitTestVisible="True"
VerticalAlignment="Top"
Background="Transparent"
Height="40"
Canvas.ZIndex="1"
Margin="48,8,0,0">
<StackPanel Orientation="Horizontal">
<Image x:Name="AppFontIcon"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Source="Assets/Square44x44Logo.png"
Width="16"
Height="16"/>
<TextBlock x:Name="AppTitle"
Text="enScore"
VerticalAlignment="Center"
Margin="12,0,0,0"
Style="{ThemeResource CaptionTextBlockStyle}"/>
</StackPanel>
</Border>
<winui:NavigationView
IsBackButtonVisible="Visible"
IsBackEnabled="{x:Bind IsBackEnabled, Mode=OneWay}"
SelectedItem="{x:Bind Selected, Mode=OneWay}"
ItemInvoked="OnItemInvoked"
IsSettingsVisible="True"
IsTitleBarAutoPaddingEnabled="False"
DisplayModeChanged="NavigationViewControl_DisplayModeChanged"
Canvas.ZIndex="0"
x:Name="navigationView">
<winui:NavigationView.MenuItems>
<winui:NavigationViewItem x:Uid="Shell_Main" Icon="Copy" helpers:NavHelper.NavigateTo="views:MainPage" />
</winui:NavigationView.MenuItems>
<i:Interaction.Behaviors>
<behaviors:NavigationViewHeaderBehavior
DefaultHeader="{x:Bind Selected.Content, Mode=OneWay}">
<behaviors:NavigationViewHeaderBehavior.DefaultHeaderTemplate>
<DataTemplate>
<Grid x:Name="headerGrid">
<TextBlock
Text="{Binding}"
Style="{ThemeResource TitleTextBlockStyle}"
Margin="{StaticResource SmallLeftRightMargin}" />
<Button Style="{ThemeResource ButtonRevealStyle}" Content="Refresh Library Contents" HorizontalAlignment="Right" Margin="0,45,8,0" Click="RefreshLibrary"/>
<Button Style="{ThemeResource ButtonRevealStyle}" Content="Import PDF To Current Folder" HorizontalAlignment="Right" Margin="0,-35,140,0" Click="AddScore"/>
<Button Style="{ThemeResource ButtonRevealStyle}" Content="Add New Folder" HorizontalAlignment="Right" Margin="0,-35,8,0" Click="AddFolderAsync"/>
<ToggleButton Style="{ThemeResource ToggleButtonRevealStyle}" x:FieldModifier="public" x:Name="tbtndelete" Content="Delete Items" HorizontalAlignment="Right" Margin="0,45,191,0" Tapped="DeleteItem"/>
</Grid>
</DataTemplate>
</behaviors:NavigationViewHeaderBehavior.DefaultHeaderTemplate>
</behaviors:NavigationViewHeaderBehavior>
</i:Interaction.Behaviors>
<Grid>
<Frame x:Name="shellFrame" />
</Grid>
</winui:NavigationView>
</Grid>
</Page>
Try to change the placement of the menu with:
PaneDisplayMode="Top"
For my case with Microsoft.UI.Xaml.Controls for Microsoft.WindowsAppSDK v1.0.0.
the showing/hidding of menu bar works fine.
Left, LeftMinimal, LeftCompact crashes the app.
I know you may expect the menu on the left, but still on the top is not that bad idea ;-) At least it works.. Greetz.
Related
I have a little question. I'm new to WPF and a strange thing happened to me. In the designer everything looks fine, but as soon as I start the application, a piece ,,cuts off"(via.photo) and it looks pretty bad. Could it be that the application is not responsive?
My XAML code:
<TabItem Header="TabItem"
Visibility="Hidden"
x:Name="Home_Page"
Background="{x:Null}"
BorderBrush="{x:Null}" Height="Auto"
Width="Auto"
>
<Border
Background="Black"
HorizontalAlignment="Center"
VerticalAlignment="Center"
Width="1340"
Height="1100"
CornerRadius="20"
>
<Border
Background="White"
CornerRadius="20"
Height="700"
Width="500"
Margin="0" HorizontalAlignment="Center" VerticalAlignment="Center"
>
<Grid
>
<TextBlock
Text="Welcome"
Width="200"
Height="200"
Foreground="Black"
FontSize="50" FontFamily="/Peel_App;component/Fonts/#Kashima Brush Demo"
>
</TextBlock>
</Grid>
</Border>
</Border>
</TabItem>
After what I edited app:
Your code has a few issues:
You're hardcoding the Margin values to position your controls. Instead, you should use proper panels (DockPanel, WrapPanel, and Grid). Use Margin property to set margin, not a position.
Use HorizontalAlignment and VerticalAlignment properties to position your elements, thus your UI would be more responsive and user-friendly.
To be able to view, how your window and its content would look like - try to set d:DesignHeght and d:DesignWidth properties on a window. Try to Google how to use them.
In the end, your code should look like following:
<TabItem Header="TabItem"
Visibility="Hidden"
x:Name="Home_Page"
Background="{x:Null}"
BorderBrush="{x:Null}"> <!-- Properties order is a bit confusing, it is better to order them by priority, or just alphabetically. -->
<Border Background="Black">
<Border Background="White"
CornerRadius="20"
Margin="0,0,93,118"> <!-- Should it have such values? Maybe just somenthing like Margin="0 0 90 120"? -->
<Grid>
<TextBlock Text="Welcome"
Foreground="Black"
FontSize="50"
FontFamily="/Peel_App;component/Fonts/#Kashima Brush Demo"/>
</Grid>
</Border>
</Border>
</TabItem>
Here's a picture of the overlay from the sample app:
Here's the git page of the Material Design In XAML Toolkit (you can download the demo project here): Toolkit:https://github.com/ButchersBoy/MaterialDesignInXamlToolkit
This is probably property somewhere in the Material Design In XAML Toolkit library and i am asking if anyone knows how to set it (or if the overlay can even be turned off).
<Window x:Class="MaterialDesignColors.WpfExample.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:wpfExample="clr-namespace:MaterialDesignColors.WpfExample"
xmlns:domain="clr-namespace:MaterialDesignColors.WpfExample.Domain"
xmlns:system="clr-namespace:System;assembly=mscorlib"
xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
xmlns:domain1="clr-namespace:MaterialDesignDemo.Domain"
xmlns:materialDesignDemo="clr-namespace:MaterialDesignDemo"
Title="Material Design in XAML" Height="800" Width="1100"
TextElement.Foreground="{DynamicResource MaterialDesignBody}"
TextElement.FontWeight="Regular"
TextElement.FontSize="13"
TextOptions.TextFormattingMode="Ideal"
TextOptions.TextRenderingMode="Auto"
Background="{DynamicResource MaterialDesignPaper}"
FontFamily="{StaticResource MaterialDesignFont}" Icon="favicon.ico">
<Window.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Button.xaml" />
<ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Shadows.xaml" />
<ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.ToggleButton.xaml" />
</ResourceDictionary.MergedDictionaries>
<!-- data template used for the dialogs example, defines a View for a ViewModel of type DateTime -->
<DataTemplate DataType="{x:Type system:DateTime}">
<StackPanel Margin="16">
<TextBlock>England win the World Cup:</TextBlock>
<TextBlock Margin="0 8 0 0" Text="{Binding }" />
<TextBlock Margin="0 8 0 0" >You will never see that again.</TextBlock>
<Button Margin="0 8 0 0" IsDefault="True" Command="{x:Static materialDesign:DialogHost.CloseDialogCommand}" Style="{DynamicResource MaterialDesignFlatButton}">AWESOME</Button>
</StackPanel>
</DataTemplate>
</ResourceDictionary>
</Window.Resources>
<materialDesign:DialogHost Identifier="RootDialog">
<materialDesign:DrawerHost IsLeftDrawerOpen="{Binding ElementName=MenuToggleButton, Path=IsChecked}">
<materialDesign:DrawerHost.LeftDrawerContent>
<DockPanel MinWidth="212">
<ToggleButton Style="{StaticResource MaterialDesignHamburgerToggleButton}"
DockPanel.Dock="Top"
HorizontalAlignment="Right" Margin="16"
IsChecked="{Binding ElementName=MenuToggleButton, Path=IsChecked, Mode=TwoWay}" />
<ListBox x:Name="DemoItemsListBox" Margin="0 16 0 16" SelectedIndex="0"
PreviewMouseLeftButtonUp="UIElement_OnPreviewMouseLeftButtonUp">
<ListBox.ItemTemplate>
<DataTemplate DataType="domain:DemoItem">
<TextBlock Text="{Binding Name}" Margin="32 0 32 0" />
</DataTemplate>
</ListBox.ItemTemplate>
<domain:DemoItem Name="Home">
...
<domain:DemoItem Name="Shadows">
<domain:DemoItem.Content>
<wpfExample:Shadows />
</domain:DemoItem.Content>
</domain:DemoItem>
</ListBox>
</DockPanel>
</materialDesign:DrawerHost.LeftDrawerContent>
<DockPanel>
<materialDesign:ColorZone Padding="16" materialDesign:ShadowAssist.ShadowDepth="Depth2"
Mode="PrimaryMid" DockPanel.Dock="Top">
<DockPanel>
<ToggleButton Style="{StaticResource MaterialDesignHamburgerToggleButton}" IsChecked="False"
x:Name="MenuToggleButton"/>
<materialDesign:PopupBox DockPanel.Dock="Right" PlacementMode="BottomAndAlignRightEdges" StaysOpen="False">
<StackPanel>
<Button Content="Hello World" Click="MenuPopupButton_OnClick"/>
<Button Content="Nice Popup" Click="MenuPopupButton_OnClick"/>
<Button Content="Goodbye" Click="MenuPopupButton_OnClick"/>
</StackPanel>
</materialDesign:PopupBox>
<TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="22">Material Design In XAML Toolkit</TextBlock>
</DockPanel>
</materialDesign:ColorZone>
<ContentControl Margin="16" Content="{Binding ElementName=DemoItemsListBox, Path=SelectedItem.Content}" />
</DockPanel>
</materialDesign:DrawerHost>
</materialDesign:DialogHost>
</Window>
The black shade is due to a grid defined in Generic.xaml:
<Grid x:Name="PART_ContentCover" Background="{x:Null}" Opacity="0"
IsHitTestVisible="False" Focusable="False" />
Which is animated to set the opacity to 0.56 when the drawer is drawn. Unfortunatelly this grid does not belong to any template so you cannot change it in client xaml.
The other option is to change the shade's black brush which is also defined in Generic.xaml:
<SolidColorBrush x:Key="BlackBackground" Color="Black" />
But this is also something I wouldn't know how to change from a client xaml, so the only advice until someone with more WPF skillz gives a better option is to simply recompile the source and change the black brush to:
<SolidColorBrush x:Key="BlackBackground" Color="#00000000" />
Alternatively you can use the flyout control which is shown in the other demo that does not have the dark shade feature but other than that is the same.
Update: I've found one way to solve this. You can subclass DrawerHost like this:
public class DrawerHostEx : DrawerHost
{
public DrawerHostEx()
{
}
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
var grid = GetTemplateChild(TemplateContentCoverPartName) as System.Windows.Controls.Grid;
grid.Visibility = System.Windows.Visibility.Collapsed;
}
}
Then you simply replace DrawerHost with DrawerHostEx in the XAML.
i do have a problem with binding the visibility of my usercontrol.
The binding to a Dependency Property of type Visibility works fine and the correct value (in this case Collapsed) is held by the DP. The content of my Grid within the UserControl is set to collapsed, but the hole control doesnt collapse. It still keeps the space occupied defined by with and heigth, as referenced in the xaml.
EDIT: i found out, that the problem is that i set width and height in the xaml where i reference my usercontrol. if i don't do this, the control collapses correct (therefore binding works fine). But i need to set width and heigth in case the usercontrol is visible.
Any idea how i can solve this problem?
<my:MenuButtonBase x:Class="bxSuite.Controls.MenuButtonLarge"
xmlns:my="clr-namespace:bxSuite.Controls"
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"
Background="Black"
>
<Grid Visibility="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type UserControl}}, Path=ButtonVisibility}" >
<StackPanel>
<Image Source="{Binding ButtonImageSource}" Margin="5,10,5,5" Width="48" Height="48" VerticalAlignment="Top" HorizontalAlignment="Center" />
<TextBlock Text="{Binding FunctionHeader}" Foreground="White" TextWrapping="Wrap" TextAlignment="Center" Padding="5,5,5,5" FontSize="12" />
</StackPanel>
</Grid>
</my:MenuButtonBase>
In XAML i reference my usercontrol like this (where the Converter produces the visibility-state correctly):
<my:MenuButtonLarge Name="btnInEuqipment" ButtonVisibility="{Binding Path=User, Converter={StaticResource ConverterUserRightVisibility}, ConverterParameter=5}" VerticalAlignment="Top" FunctionHeader="{lex:Loc Key=MenuButton_InEquipment}" Width="130" ButtonImageSource="/bxSuite.RolloutManager;component/Images/inequipment_48x48.png" BackgroundEnabled="#FF0694FD" BackgroundHover="#FF0072C6" MenuButtonClick="btnInEuqipment_MenuButtonClick" Height="95" Margin="5,10,0,0" />
Try set the visibility of the user control instead of the grid, should work.
Your code should be like this.
<my:MenuButtonBase x:Class="bxSuite.Controls.MenuButtonLarge"
xmlns:my="clr-namespace:bxSuite.Controls"
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"
Visibility="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type UserControl}}, Path=ButtonVisibility}"
Background="Black">
<Grid>
<StackPanel>
<Image Source="{Binding ButtonImageSource}"
Margin="5,10,5,5"
Width="48"
Height="48"
VerticalAlignment="Top"
HorizontalAlignment="Center" />
<TextBlock Text="{Binding FunctionHeader}"
Foreground="White"
TextWrapping="Wrap"
TextAlignment="Center"
Padding="5,5,5,5"
FontSize="12" />
</StackPanel>
</Grid>
Dont forget to update the RelativeSource of your bind.
I have a XAML page in a Windows 8.1 Store App. I set the data context for a ListView but I initially have it collapsed. What I am trying to do is toggle the visibility of some of the elements in the ListView before making it visible. But it doesn't load them unless it becomes visible. So, to forced it to load the items, I am trying to set "IsVirtualizing" to false so that I don't have to worry about it (and I don't mind the hit in performance since I won't have that many items). But for all the examples I look at, all I get is
The property "IsVirtualizing" does not have an accessible setter.
Not sure what is going on here.
Here is the relevant piece of code with the other contents stripped out.
<common:LayoutAwarePage
x:Class="FlashMe.DeckView"
DataContext="{Binding DefaultViewModel, RelativeSource={RelativeSource Self}}"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:FlashMe"
xmlns:common="using:FlashMe.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
>
<ScrollViewer x:Name="deckScrollViewer" Grid.Row="1" VerticalScrollMode="Disabled" HorizontalScrollMode="Enabled" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Disabled" Margin="0,15,0,0">
<StackPanel x:Name="deckStackPanel" Orientation="Horizontal">
<Grid Width="100" x:Name="MarginBuffer" />
<ListView x:Name="cardsListViewDisplay" Visibility="Collapsed" SelectionMode="None" Width="500" ItemsSource="{Binding Path=FlashCardsAsList}" VirtualizingStackPanel.IsVirtualizing="False">
<ListView.ItemTemplate>
<DataTemplate>
<Border>
<StackPanel Orientation="Vertical" Width="490" Height="400" RightTapped="FlashCardRightClicked">
<Grid Width="490" Height="200" Background="Gainsboro">
<TextBlock Text="{Binding Path=Front}"
Foreground="Black"
Style="{StaticResource GroupHeaderTextStyle}"
Margin="4,0,4,4"
FontWeight="SemiBold"
VerticalAlignment="Center"
HorizontalAlignment="Center"
TextWrapping="Wrap"
MaxWidth="410"/>
</Grid>
<Grid Width="500" Height="200" Background="{Binding ElementName=deckStackPanel, Path=DataContext.DeckColorBrush}">
<TextBlock Text="{Binding Path=Back}"
Foreground="White"
Style="{StaticResource GroupHeaderTextStyle}"
Margin="4,0,0,4"
FontWeight="SemiBold"
VerticalAlignment="Center"
HorizontalAlignment="Center"
TextWrapping="Wrap"
MaxWidth="410"/>
</Grid>
</StackPanel>
</Border>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackPanel>
</ScrollViewer>
</common:LayoutAwarePage>
In Windows Store Apps, the IsVirtualizing property is read-only.
From the Remarks section on the VirtualizingStackPanel.IsVirtualizingProperty page on MSDN:
VirtualizingStackPanel.IsVirtualizing is an atypical attached property
because it does not have a Set accessor, and thus is not really a XAML
attached property with a markup usage. Instead,
VirtualizingStackPanel.IsVirtualizing functions as a sentinel whereby
child elements can query the VirtualizingStackPanel parent, and
determine whether virtualization is being used. ...
Trying to implement a conversation view in a wp8.1 app using telerik controls, a platform im not familiar with. I keep getting a reference error on build:
Error 3 The name "RadPointerContentControl" does not exist in the namespace "clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Primitives". D:\Visual Studio Workspace\Sports App\Sports App Prototype\Sports App Prototype\MainPage.xaml 74 29 Sports App Prototype
This error is really confusing me. I have referenced
xmlns:telerikPrimitives="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Primitives"
in the XAML document but cannot seem to get it working properly, as if its just not seeing the reference properly, or is missing it at build time, tbh i havent a clue!
Any help would be much appreciated.
EDIT: XAML
<Page xmlns:Maps="using:Windows.UI.Xaml.Controls.Maps"
x:Class="Sports_App_Prototype.MainPage"
xmlns:primitives="clr-namespace:Telerik.Windows.Controls.Primitives;assembly=Telerik.Windows.Controls.Primitives"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Sports_App_Prototype"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid>
<Pivot>
<Flyout x:Name="registration" >
<Grid Height="320">
<TextBlock Margin="0,0,0,309">
Register New User or Login
</TextBlock>
<TextBox Margin="10,59,10,0" Text="Password">
</TextBox>
<TextBox Margin="10,16,10,0" Text="Username">
</TextBox>
<CheckBox Margin="172,99,0,0" Content="Accept">
</CheckBox>
<Button Content="Register/Login" Margin="10,99,0,164">
</Button>
</Grid>
</Flyout>
<PivotItem Header="map view">
<StackPanel>
<Maps:MapControl Height="450" Width="355" />
<Button x:Name="FilterButton" HorizontalAlignment="Center" Click="Filter_Click" Content="Filter" Margin="126,0,126.667,0" Height="61"/>
</StackPanel>
</PivotItem>
<Flyout x:Name="Filter">
<Grid>
<StackPanel>
<TextBlock>
Filter Users
</TextBlock>
<RichTextBlock>
<!-- Stuff goes here for RTB -->
</RichTextBlock>
<CheckBox>
Dynamically generated from user #1
</CheckBox>
<CheckBox>
Dynamically generated from user #2
</CheckBox>
<CheckBox>g
Dynamically generated from user #3
</CheckBox>
<CheckBox>
Dynamically generated from user #4
</CheckBox>
</StackPanel>
</Grid>
</Flyout>
<PivotItem Header="chat">
<DataTemplate>
<Grid Margin="12">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="3*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<telerikPrimitives:RadPointerContentControl Background="{StaticResource PhoneAccentBrush}"
TargetPoint="-150,-300">
<telerikPrimitives:RadPointerContentControl.PointerTemplate>
<DataTemplate>
<Polygon Width="12"
Height="24"
Points="0,0 12,0 12,12 0,24"
StrokeThickness="0"
Fill="{StaticResource PhoneAccentBrush}"
RenderTransformOrigin="0.5, 0.5">
<Polygon.RenderTransform>
<ScaleTransform ScaleX="-1"/>
</Polygon.RenderTransform>
</Polygon>
</DataTemplate>
</telerikPrimitives:RadPointerContentControl.PointerTemplate>
<StackPanel>
<TextBlock Text="{Binding Path=Text}"
TextWrapping="Wrap"
Margin="12"/>
<TextBlock Text="{Binding Path=TimeStamp}"
Margin="12, 0, 12, 12"
HorizontalAlignment="Right"/>
</StackPanel>
</telerikPrimitives:RadPointerContentControl>
</Grid>
</DataTemplate>
</PivotItem>
</Pivot>
</Grid>
This is complaining that it cannot find the reference to the .DLL. Under references in Visual Studio, do you have the file called Telerik.Windows.Controls.Primitives added? If so, then please post your entire XAML file and I'll help you troubleshoot it.
BTW, make sure you are using a Silverlight WP8.1 app and not a WinRT app.