Develop Reference

New frame display exception after ListView SelectionChange method uwp c#

There is a ContestListView with elements:
public MainPage()
{
this.InitializeComponent();
List<int> list = new List<int>();
list.Add(2);
list.Add(3);
list.Add(5);
list.Add(7);
ContestListView.ItemsSource = list;
}
I want to navigate to another Frame when SelectionChange is.
private void ContestSelectionChange(object sender, SelectionChangedEventArgs e)
{
this.Frame.Navigate(typeof(BlankPage1));
}
But I have a problem - sometimes, when I choose element at list, the BlankPage1 starts load, but I got an unhandled exception
{"Unspecified error\r\n\r\nUnspecified error\r\n"}
at this place
#if DEBUG && !DISABLE_XAML_GENERATED_BREAK_ON_UNHANDLED_EXCEPTION
UnhandledException += (sender, e) =>
{
if (global::System.Diagnostics.Debugger.IsAttached) global::System.Diagnostics.Debugger.Break();
};
#endif
This exception can be after first SelectionChandeg, but it can be too after second, third etc.
There is BlankPage1 XAML:
<Page
x:Class="Contests.BlankPage1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Contests"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.TopAppBar>
<CommandBar Foreground="White">
<CommandBar.Background>
<ImageBrush Stretch="Fill" ImageSource="Assets/app02_0013_panel_main.png"/>
</CommandBar.Background>
<CommandBar.SecondaryCommands>
<AppBarButton Label="LogOut" Click="onClick"/>
</CommandBar.SecondaryCommands>
</CommandBar>
</Page.TopAppBar>
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<ScrollViewer>
<RelativePanel>
<TextBlock x:Name="txtContestName"
Text="TestTest "
Foreground="DarkOliveGreen"
RelativePanel.AlignLeftWithPanel="True"
RelativePanel.Below=""
TextWrapping="Wrap"
FontSize="20"
Margin="5,10,0,10"/>
<TextBlock x:Name="CategoryExpiration" FontSize="12"
RelativePanel.AlignLeftWithPanel="True"
RelativePanel.Below="txtContestName"
Margin="5,0,0,10">
<Run x:Name="txtCategory" Text="Test "/>
<Run x:Name="txtExpiration" Text="2016-05-23" Foreground="Green"/>
</TextBlock>
<RelativePanel x:Name="QuestionPanel" RelativePanel.Below="CategoryExpiration"
RelativePanel.AlignLeftWithPanel="True"
RelativePanel.AlignRightWithPanel="True"
Background="Green"
Margin="5,0,5,5">
<TextBlock x:Name="textblock1" Text="Question:" Foreground="White"
RelativePanel.AlignLeftWithPanel="True"
Margin="5,5,5,0"/>
<TextBlock x:Name="txtQuestion" Foreground="White"
Text="Test?"
RelativePanel.AlignHorizontalCenterWithPanel="True"
RelativePanel.Below="textblock1"
TextWrapping="Wrap"
Margin="10, 5" TextAlignment="Center"/>
<TextBox x:Name="AnswerText" PlaceholderText="Test"
RelativePanel.Below="txtQuestion"
RelativePanel.AlignRightWithPanel="True"
RelativePanel.AlignLeftWithPanel="True"
Margin="5,5"/>
<Button x:Name="bSendAnswer" Content="Test"
RelativePanel.Below="AnswerText"
RelativePanel.AlignHorizontalCenterWithPanel="True"
Foreground="White"
Margin="5,5" Width="335"/>
</RelativePanel>
<RelativePanel x:Name="OrgPanel" RelativePanel.Below="QuestionPanel"
RelativePanel.AlignLeftWithPanel="True"
RelativePanel.AlignRightWithPanel="True"
Margin="5,0,5,5" BorderBrush="Gray">
<TextBlock x:Name="textblock2" Text="Organizator" Foreground="Green"
RelativePanel.AlignLeftWithPanel="True"
Margin="5,5,5,0"/>
<TextBlock x:Name="Org" Text="Test"
RelativePanel.Below="textblock2"
Foreground="DarkGreen"
FontSize="12"
RelativePanel.AlignRightWithPanel="True"
RelativePanel.AlignLeftWithPanel="True"
Margin="5,5"/>
</RelativePanel>
<RelativePanel x:Name="DesriptionPanel" RelativePanel.Below="OrgPanel"
RelativePanel.AlignLeftWithPanel="True"
RelativePanel.AlignRightWithPanel="True"
Margin="5,0,5,5" BorderBrush="Gray">
<TextBlock x:Name="textblock3" Text="Opis konkursu" Foreground="Green"
RelativePanel.AlignLeftWithPanel="True"
Margin="5,5,5,0"/>
<TextBlock x:Name="txtDescription" Text="test"
RelativePanel.Below="textblock3"
TextWrapping="Wrap"
Foreground="DarkGreen"
FontSize="12"
RelativePanel.AlignRightWithPanel="True"
RelativePanel.AlignLeftWithPanel="True"
Margin="5,5"/>
</RelativePanel>
<RelativePanel x:Name="PrizePanel" RelativePanel.Below="DesriptionPanel"
RelativePanel.AlignLeftWithPanel="True"
RelativePanel.AlignRightWithPanel="True"
Margin="5,0,5,5" BorderBrush="Gray">
<TextBlock x:Name="textblock4" Text="Test" Foreground="Green"
RelativePanel.AlignLeftWithPanel="True"
Margin="5,5,5,0"/>
<TextBlock x:Name="txtPrize" Text=""
RelativePanel.Below="textblock4"
Foreground="DarkGreen"
TextWrapping="Wrap"
FontSize="12"
RelativePanel.AlignRightWithPanel="True"
RelativePanel.AlignLeftWithPanel="True"
Margin="5,5"/>
</RelativePanel>
</RelativePanel>
</ScrollViewer>
</Grid>
What my problem is?

Resize grid after rotation Windows phone 8.1

[![enter image description here][1]][1]I have problem with panel size in ListView. I have StackPanel in GridView and after rotation i want resize this gridview to the whole page, but after rotate stackPanel had the same widht as he had in portrait mode. Here is my code.
But when I start application on Landscape mode it is all ok and grid is resized.
<Page
x:Class="KlientWP.VypisZakazek"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:KlientWP"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" Loaded="Page_Loaded" SizeChanged="Page_SizeChanged">
<Page.Background>
<SolidColorBrush Color="{ThemeResource PhoneImagePlaceholderColor}"/>
</Page.Background>
<Grid x:Name="ContentRoot" Margin="0,9.5,0,0">
<ScrollViewer>
<Pivot Title="Přehled databáze" HorizontalAlignment="Stretch" Margin="0,0,0,0">
<PivotItem Header="Zakázky" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="10,0,20,10" >
<ListView SelectionMode="None" x:Name="ListBox1" Margin="0,0,-0.167,0.167"
HorizontalAlignment="Stretch"
ItemsSource="{Binding}" >
<ListView.ItemTemplate>
<DataTemplate>
<Grid x:Name="grdTsk" Opacity="1" Margin="0,0,0,10" Width="1500" HorizontalAlignment="Stretch" Background="#FF302E2E" ManipulationMode="All" Tapped="grdTsk_Tapped" >
<Grid.RowDefinitions>
<RowDefinition Height="20"/>
<RowDefinition Height="30"/>
</Grid.RowDefinitions>
<FlyoutBase.AttachedFlyout>
<MenuFlyout>
<MenuFlyoutItem Text="Detail zakázky" Click="Detail" />
</MenuFlyout>
</FlyoutBase.AttachedFlyout>
<TextBlock Grid.Row="1" Text="{Binding nazev1}" Width="1500" FontSize="22" TextWrapping="Wrap" HorizontalAlignment="Stretch" Margin="5,0,0,0" Visibility="Visible" FontWeight="Light" Foreground="White"/>
<!--<StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Stretch" Margin="0,0,0,0" >
<TextBlock Text="{Binding nazev}" FontSize="22" TextWrapping="Wrap" Margin="5,0,0,0" Visibility="Visible" FontWeight="Light" Foreground="White"/>
</StackPanel>
<StackPanel Orientation="Horizontal" Margin="0,0,0,0">
<TextBlock x:Name="predmetTb" Text="{Binding zakazka}" FontSize="18" Margin="5,0,0,0" TextWrapping="Wrap" />
<TextBlock Text="{Binding kod_firmy}" FontSize="18" TextWrapping="Wrap" Margin="15,0,0,0" Foreground="#FFFFF413" />
</StackPanel>
</StackPanel>-->
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</PivotItem>
</Pivot>
</ScrollViewer>
</Grid>
binding:
CultureInfo culture = new CultureInfo("cs-CZ");
DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(List<dataInfo>));
MemoryStream stream = new MemoryStream(Encoding.UTF8.GetBytes(json));
var obj = (List<dataInfo>)ser.ReadObject(stream);
List<dataInfo> VypisZakazekli = new List<dataInfo>();
VypisZakazekli.Clear();
foreach (dataInfo di in obj)
{
string iZakazka = "ID: " + di.zakazka;
string sNazev = di.nazev;
string sKod = "Firma: " + di.kod_firmy;
string sStatus = "Status: " + di.status_v;
string sDruh = di.druh_zakazky;
VypisZakazekli.Add(new dataInfo(iZakazka, sNazev, sKod, sStatus, sDruh));
}
this.ListBox1.ItemsSource = VypisZakazekli;
}

Try to add this to your listview :
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="HorizontalContentAlignment" Value="Stretch" />
</Style>
</ListView.ItemContainerStyle>

Issues creating a flipview on ItemDetailPage

I am trying to create a flipview on the an ItemDetailpage. I am using the default template provided in visual studio when creating a grid app.
Pages in the App: GroupItemsPage, GroupDetailPage, ItemDetailPage
The problem is, I am getting this error when I click on an item on the GroupItemsPage or GroupDetailPage:
Object reference not set to an instance of an object.
Error details:
System.NullReferenceException was unhandled by user code
HResult=-2147467261
Message=Object reference not set to an instance of an object.
Source=AppError
StackTrace: at AppError.ItemDetailPage.<navigationHelper_LoadState>d__0.MoveNext()
This is my code:
GroupItemsPage.xaml
<Page
x:Name="pageRoot"
x:Class="AppError.GroupedItemsPage"
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:AppError"
xmlns:data="using:AppError.Data"
xmlns:common="using:AppError.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<x:String x:Key="ChevronGlyph"></x:String>
<!--
Collection of grouped items displayed by this page, bound to a subset
of the complete item list because items in groups cannot be virtualized
-->
<CollectionViewSource
x:Name="groupedItemsViewSource"
Source="{Binding Groups}"
IsSourceGrouped="true"
ItemsPath="Items"
d:Source="{Binding Groups, Source={d:DesignData Source=/DataModel/SampleData.json, Type=data:SampleDataSource}}"/>
</Page.Resources>
<!--
This grid acts as a root panel for the page that defines two rows:
* Row 0 contains the back button and page title
* Row 1 contains the rest of the page layout
-->
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid.ChildrenTransitions>
<TransitionCollection>
<EntranceThemeTransition/>
</TransitionCollection>
</Grid.ChildrenTransitions>
<Grid.RowDefinitions>
<RowDefinition Height="140"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!-- Horizontal scrolling grid -->
<GridView
x:Name="itemGridView"
AutomationProperties.AutomationId="ItemGridView"
AutomationProperties.Name="Grouped Items"
Grid.RowSpan="2"
Padding="116,137,40,46"
ItemsSource="{Binding Source={StaticResource groupedItemsViewSource}}"
SelectionMode="None"
IsSwipeEnabled="false"
IsItemClickEnabled="True"
ItemClick="ItemView_ItemClick">
<GridView.ItemTemplate>
<DataTemplate>
<Grid HorizontalAlignment="Left" Width="250" Height="250">
<Border Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}">
<Image Source="{Binding ImagePath}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}"/>
</Border>
<StackPanel VerticalAlignment="Bottom" Background="{ThemeResource ListViewItemOverlayBackgroundThemeBrush}">
<TextBlock Text="{Binding Title}" Foreground="{ThemeResource ListViewItemOverlayForegroundThemeBrush}" Style="{StaticResource TitleTextBlockStyle}" Height="60" Margin="15,0,15,0"/>
<TextBlock Text="{Binding Subtitle}" Foreground="{ThemeResource ListViewItemOverlaySecondaryForegroundThemeBrush}" Style="{StaticResource CaptionTextBlockStyle}" TextWrapping="NoWrap" Margin="15,0,15,10"/>
</StackPanel>
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
<GridView.ItemsPanel>
<ItemsPanelTemplate>
<ItemsWrapGrid GroupPadding="0,0,70,0"/>
</ItemsPanelTemplate>
</GridView.ItemsPanel>
<GridView.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<Grid Margin="0,0,0,2">
<Button Foreground="{ThemeResource ApplicationHeaderForegroundThemeBrush}"
AutomationProperties.Name="Group Title"
Click="Header_Click"
Style="{StaticResource TextBlockButtonStyle}" >
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Title}" Margin="0,-11,10,10" Style="{StaticResource SubheaderTextBlockStyle}" TextWrapping="NoWrap" />
<TextBlock Text="{StaticResource ChevronGlyph}" FontFamily="Segoe UI Symbol" Margin="0,-11,0,10" Style="{StaticResource SubheaderTextBlockStyle}" TextWrapping="NoWrap" />
</StackPanel>
</Button>
</Grid>
</DataTemplate>
</GroupStyle.HeaderTemplate>
</GroupStyle>
</GridView.GroupStyle>
</GridView>
<!-- Back button and page title -->
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="120"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Button x:Name="backButton" Margin="39,59,39,0" Command="{Binding NavigationHelper.GoBackCommand, ElementName=pageRoot}"
Style="{StaticResource NavigationBackButtonNormalStyle}"
VerticalAlignment="Top"
AutomationProperties.Name="Back"
AutomationProperties.AutomationId="BackButton"
AutomationProperties.ItemType="Navigation Button"/>
<TextBlock x:Name="pageTitle" Text="{StaticResource AppName}" Style="{StaticResource HeaderTextBlockStyle}" Grid.Column="1"
IsHitTestVisible="false" TextWrapping="NoWrap" VerticalAlignment="Bottom" Margin="0,0,30,40"/>
</Grid>
</Grid>
GroupItemsPage.xaml.cs
namespace AppError
{
public sealed partial class GroupedItemsPage : Page
{
private NavigationHelper navigationHelper;
private ObservableDictionary defaultViewModel = new ObservableDictionary();
public NavigationHelper NavigationHelper
{
get { return this.navigationHelper; }
}
public ObservableDictionary DefaultViewModel
{
get { return this.defaultViewModel; }
}
public GroupedItemsPage()
{
this.InitializeComponent();
this.navigationHelper = new NavigationHelper(this);
this.navigationHelper.LoadState += navigationHelper_LoadState;
}
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;
}
void Header_Click(object sender, RoutedEventArgs e)
{
// Determine what group the Button instance represents
var group = (sender as FrameworkElement).DataContext;
// Navigate to the appropriate destination page, configuring the new page
// by passing required information as a navigation parameter
this.Frame.Navigate(typeof(GroupDetailPage), ((SampleDataGroup)group).UniqueId);
}
void ItemView_ItemClick(object sender, ItemClickEventArgs e)
{
// Navigate to the appropriate destination page, configuring the new page
// by passing required information as a navigation parameter
var itemId = ((SampleDataItem)e.ClickedItem).UniqueId;
this.Frame.Navigate(typeof(ItemDetailPage), itemId);
}
}
GroupDetailpage.xaml
<Page
x:Name="pageRoot"
x:Class="AppError.GroupDetailPage"
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:AppError"
xmlns:data="using:AppError.Data"
xmlns:common="using:AppError.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<!-- Collection of items displayed by this page -->
<CollectionViewSource
x:Name="itemsViewSource"
Source="{Binding Items}"
d:Source="{Binding Groups[0].Items, Source={d:DesignData Source=/DataModel/SampleData.json, Type=data:SampleDataSource}}"/>
</Page.Resources>
<!--
This grid acts as a root panel for the page that defines two rows:
* Row 0 contains the back button and page title
* Row 1 contains the rest of the page layout
-->
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
DataContext="{Binding Group}"
d:DataContext="{Binding Groups[0], Source={d:DesignData Source=/DataModel/SampleData.json, Type=data:SampleDataSource}}">
<Grid.ChildrenTransitions>
<TransitionCollection>
<EntranceThemeTransition/>
</TransitionCollection>
</Grid.ChildrenTransitions>
<Grid.RowDefinitions>
<RowDefinition Height="140"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!-- Horizontal scrolling grid -->
<GridView
x:Name="itemGridView"
AutomationProperties.AutomationId="ItemGridView"
AutomationProperties.Name="Items In Group"
TabIndex="1"
Grid.RowSpan="2"
Padding="120,126,120,50"
ItemsSource="{Binding Source={StaticResource itemsViewSource}}"
SelectionMode="None"
IsSwipeEnabled="false"
IsItemClickEnabled="True"
ItemClick="ItemView_ItemClick">
<GridView.ItemTemplate>
<DataTemplate>
<Grid Height="110" Width="480" Margin="10">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border Background="{ThemeResource ListViewItemPlaceholderBackgroundThemeBrush}" Width="110" Height="110">
<Image Source="{Binding ImagePath}" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}"/>
</Border>
<StackPanel Grid.Column="1" VerticalAlignment="Top" Margin="10,0,0,0">
<TextBlock Text="{Binding Title}" Style="{StaticResource TitleTextBlockStyle}" TextWrapping="NoWrap"/>
<TextBlock Text="{Binding Subtitle}" Style="{StaticResource CaptionTextBlockStyle}" TextWrapping="NoWrap"/>
<TextBlock Text="{Binding Description}" Style="{StaticResource BodyTextBlockStyle}" MaxHeight="60"/>
</StackPanel>
</Grid>
</DataTemplate>
</GridView.ItemTemplate>
<GridView.Header>
<StackPanel Width="480" Margin="0,4,14,0">
<TextBlock Text="{Binding Subtitle}" Margin="0,0,0,20" Style="{StaticResource SubheaderTextBlockStyle}" MaxHeight="60"/>
<Image Source="{Binding ImagePath}" Height="400" Margin="0,0,0,20" Stretch="UniformToFill" AutomationProperties.Name="{Binding Title}"/>
<TextBlock Text="{Binding Description}" Margin="0,0,0,0" Style="{StaticResource BodyTextBlockStyle}"/>
</StackPanel>
</GridView.Header>
<GridView.ItemContainerStyle>
<Style TargetType="FrameworkElement">
<Setter Property="Margin" Value="52,0,0,2"/>
</Style>
</GridView.ItemContainerStyle>
</GridView>
<!-- Back button and page title -->
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="120"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Button x:Name="backButton" Margin="39,59,39,0" Command="{Binding NavigationHelper.GoBackCommand, ElementName=pageRoot}"
Style="{StaticResource NavigationBackButtonNormalStyle}"
VerticalAlignment="Top"
AutomationProperties.Name="Back"
AutomationProperties.AutomationId="BackButton"
AutomationProperties.ItemType="Navigation Button"/>
<TextBlock x:Name="pageTitle" Text="{Binding Title}" Style="{StaticResource HeaderTextBlockStyle}" Grid.Column="1"
IsHitTestVisible="false" TextWrapping="NoWrap" VerticalAlignment="Bottom" Margin="0,0,30,40"/>
</Grid>
</Grid>
GroupDetailPage.xaml.cs
namespace AppError
{
public sealed partial class GroupDetailPage : Page
{
private NavigationHelper navigationHelper;
private ObservableDictionary defaultViewModel = new ObservableDictionary();
public NavigationHelper NavigationHelper
{
get { return this.navigationHelper; }
}
public ObservableDictionary DefaultViewModel
{
get { return this.defaultViewModel; }
}
public GroupDetailPage()
{
this.InitializeComponent();
this.navigationHelper = new NavigationHelper(this);
this.navigationHelper.LoadState += navigationHelper_LoadState;
}
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 group = await SampleDataSource.GetGroupAsync((String)e.NavigationParameter);
this.DefaultViewModel["Group"] = group;
this.DefaultViewModel["Items"] = group.Items;
}
void ItemView_ItemClick(object sender, ItemClickEventArgs e)
{
// Navigate to the appropriate destination page, configuring the new page
// by passing required information as a navigation parameter
var itemId = ((SampleDataItem)e.ClickedItem).UniqueId;
this.Frame.Navigate(typeof(ItemDetailPage), itemId);
}
}
ItemDetailPage.xaml
<Page
x:Name="pageRoot"
x:Class="AppError.ItemDetailPage"
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:AppError"
xmlns:data="using:AppError.Data"
xmlns:common="using:AppError.Common"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<CollectionViewSource
x:Name="itemViewSource"
Source="{Binding Items}"
d:Source="{Binding Groups[0].Items, Source={d:DesignData Source=/DataModel/SampleData.json, Type=data:SampleDataSource}}"/>
</Page.Resources>
<!--
This grid acts as a root panel for the page that defines two rows:
* Row 0 contains the back button and page title
* Row 1 contains the rest of the page layout
-->
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
DataContext="{Binding Item}"
d:DataContext="{Binding Groups[0].Items[0], Source={d:DesignData Source=/DataModel/SampleData.json, Type=data:SampleDataSource}}">
<Grid.ChildrenTransitions>
<TransitionCollection>
<EntranceThemeTransition/>
</TransitionCollection>
</Grid.ChildrenTransitions>
<Grid.RowDefinitions>
<RowDefinition Height="140"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!--
TODO: Content should be placed within the following grid
to show details for the current item
-->
<FlipView
Grid.Row="1"
x:Name="flipView"
Margin="50,0,0,0"
ItemsSource="{Binding Source={StaticResource itemViewSource}}">
<FlipView.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="500"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<StackPanel>
<Border>
<Image Source="{Binding ImagePath}"/>
</Border>
<TextBlock Text="{Binding Description}" Padding="0,30,0,0" TextWrapping="Wrap"/>
</StackPanel>
<Grid Grid.Column="1" Margin="30,0,0,0">
<TextBlock Text="{Binding Content}" TextWrapping="Wrap"/>
</Grid>
</Grid>
</DataTemplate>
</FlipView.ItemTemplate>
</FlipView>
<!-- Back button and page title -->
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="120"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Button x:Name="backButton" Margin="39,59,39,0" Command="{Binding NavigationHelper.GoBackCommand, ElementName=pageRoot}"
Style="{StaticResource NavigationBackButtonNormalStyle}"
VerticalAlignment="Top"
AutomationProperties.Name="Back"
AutomationProperties.AutomationId="BackButton"
AutomationProperties.ItemType="Navigation Button"/>
<TextBlock x:Name="pageTitle" Text="{Binding Title}" Style="{StaticResource HeaderTextBlockStyle}" Grid.Column="1"
IsHitTestVisible="false" TextWrapping="NoWrap" VerticalAlignment="Bottom" Margin="0,0,30,40"/>
</Grid>
</Grid>
ItemDetailPage.xaml.cs
namespace AppError
{
public sealed partial class ItemDetailPage : Page
{
private NavigationHelper navigationHelper;
private ObservableDictionary defaultViewModel = new ObservableDictionary();
public NavigationHelper NavigationHelper
{
get { return this.navigationHelper; }
}
public ObservableDictionary DefaultViewModel
{
get { return this.defaultViewModel; }
}
public ItemDetailPage()
{
this.InitializeComponent();
this.navigationHelper = new NavigationHelper(this);
this.navigationHelper.LoadState += navigationHelper_LoadState;
}
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 group = await SampleDataSource.GetGroupAsync((String)e.NavigationParameter);
var item = await SampleDataSource.GetItemAsync((String)e.NavigationParameter);
this.DefaultViewModel["Group"] = group;
this.DefaultViewModel["Items"] = group.Items;
this.flipView.SelectedItem = item;
}
}

Getting the parent of usercontrol inside Dispatcher.BeginInvoke

Am having a Main window in my WPF application inside which am having a tabcontrol.I need to select the tabitem based on the name i pass.Each of the tabitem will contain a user control.But my problem is am not able to get the parent of the usercontrol using Parent property.Its returning null only always.Can anyone help me out.
public void selectingTab()
{
Dispatcher.BeginInvoke((Action)(() =>
{
string name = todisplayChat.GetValue<string>("FromMessenger");
string msg = todisplayChat.GetValue<string>("ChatSent");
NewChatWindow childWindow = this as NewChatWindow;
MainChatWindow parentWindow = VisualTreeHelper.GetParent(childWindow) as MainChatWindow;
//Am getting null as the value of parentWindow after the execution of this line
TabControl tabcontrolHome = parentWindow.tabcontrol_Chatwindow;
TabItem existingTab = tabcontrolHome.Items.OfType<TabItem>().SingleOrDefault(n => n.Name == name);
childWindow = (NewChatWindow)existingTab.Content;
childWindow.richtxtbox_chatwindow.AppendText(Environment.NewLine + name + " : " + msg);
}));
}
MainChatWindow.XAML
<Window x:Class="Ping.MainChatWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="600" Width="700" Icon="F:\Dhivya\C#\Personal\ChatApplication\CurrentlyWorking-Important\Ping\Ping\images\ping_logo.png" ResizeMode="CanMinimize" WindowStartupLocation="CenterScreen" WindowStyle="None" Foreground="{x:Null}" BorderBrush="#FF87A4DB" BorderThickness="2">
<Grid>
<Label Content="Ping" Height="30" HorizontalAlignment="Left" Name="lbl_Titlebar" VerticalAlignment="Top" Width="700" Background="#FF87A4DB" FontFamily="Arial" FontSize="17" Foreground="White" />
<Image Height="20" HorizontalAlignment="Left" Margin="635,5,0,0" Name="img_Minimizebutton" Stretch="Fill" VerticalAlignment="Top" Width="20" Source="F:\Dhivya\C#\Personal\ChatApplication\CurrentlyWorking-Important\Ping\Ping\images\minimize_userpage.png" />
<!--<Label Height="25" HorizontalAlignment="Left" Margin="665,5,0,0" VerticalAlignment="Top" Width="20">-->
<Image MouseEnter="close_icon_MouseEnter_1" MouseDown="close_icon_MouseDown_1" Height="20" HorizontalAlignment="Left" Margin="665,5,0,0" Name="close_icon" Stretch="Fill" VerticalAlignment="Top" Width="20" Source="F:\Dhivya\C#\Personal\ChatApplication\CurrentlyWorking-Important\Ping\Ping\images\close_userpage.png" />
<!--</Label>-->
<Label Content="Groups" Height="28" HorizontalAlignment="Left" Margin="12,46,0,0" Name="lbl_Groups" VerticalAlignment="Top" Background="#FF87A4DB" Foreground="White" BorderBrush="{x:Null}" Width="245" FontSize="16" FontFamily="Arial" />
<RichTextBox ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto" Height="175" HorizontalAlignment="Left" Margin="12,73,0,0" Name="richtxtbox_Groups" VerticalAlignment="Top" Width="245" FontFamily="Arial" />
<Label Background="#FF87A4DB" BorderBrush="{x:Null}" Content="Online Buddies" FontFamily="Arial" FontSize="16" Foreground="White" Height="28" HorizontalAlignment="Left" Margin="12,260,0,0" Name="lbl_Onlinebuddies" VerticalAlignment="Top" Width="245" />
<Grid ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto" Height="298" HorizontalAlignment="Left" Margin="12,288,0,0" Name="richtxtbox_Onlinebuddies" VerticalAlignment="Top" Width="245"></Grid>
<!--<RichTextBox ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto" Height="298" HorizontalAlignment="Left" Margin="12,288,0,0" Name="richtxtbox_Onlinebuddies" VerticalAlignment="Top" Width="245" FontFamily="Arial" />-->
<TabControl Height="540" HorizontalAlignment="Left" Margin="274,46,0,0" Name="tabcontrol_Chatwindow" VerticalAlignment="Top" Width="410">
<TabItem Header="My Profile" Name="ProfileTab">
</TabItem>
</TabControl>
</Grid>
NewChatWindow.Xaml
<UserControl x:Class="Ping.NewChatWindow"
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"
mc:Ignorable="d"
d:DesignHeight="540" d:DesignWidth="410">
<Grid>
<TextBox LostFocus="txt_Userinput_LostFocus_1" Foreground="Gray" GotFocus="txt_Userinput_GotFocus_1" KeyDown="txt_Userinput_KeyDown_1" Height="65" HorizontalAlignment="Left" Margin="13,161,0,0" Name="txt_Userinput" VerticalAlignment="Top" Width="378" FontFamily="Arial" Text="Enter Your Words Here" />
<RichTextBox ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Auto" Height="246" HorizontalAlignment="Left" Margin="13,253,0,0" Name="richtxtbox_chatwindow" VerticalAlignment="Top" Width="378" FontFamily="Arial" />
<Image Height="93" HorizontalAlignment="Left" Margin="36,36,0,0" Name="image2" Stretch="Fill" VerticalAlignment="Top" Width="65" Source="F:\Dhivya\C#\Personal\ChatApplication\CurrentlyWorking-Important\Ping\Ping\images\user_logo.png"/>
<Label Content="Label" Height="37" HorizontalAlignment="Left" Margin="124,24,0,0" Name="lbl_Username" VerticalAlignment="Top" Width="278" FontSize="24" />
<Label Content="Label" Height="28" HorizontalAlignment="Left" Margin="125,52,0,0" Name="lbl_Statusmsg" VerticalAlignment="Top" Width="284" />
<Image Height="40" Width="30" HorizontalAlignment="Left" Margin="131,89,0,0" Name="img_Profileview" Stretch="Fill" VerticalAlignment="Top" Source="F:\Dhivya\C#\Personal\ChatApplication\CurrentlyWorking-Important\Ping\Ping\images\user_logo.png" ToolTip="Add contact"/>
<Image MouseDown="img_Sendingfile_MouseDown_1" Height="40" Width="40" HorizontalAlignment="Left" Margin="191,89,0,0" Name="img_Sendingfile" Stretch="Fill" VerticalAlignment="Top" Source="F:\Dhivya\C#\Personal\ChatApplication\CurrentlyWorking-Important\Ping\Ping\images\sendingfile_icon.png" ToolTip="Fileupload"/>
<Image Height="40" Width="40" HorizontalAlignment="Left" Margin="261,89,0,0" Name="img_Videochat" Stretch="Fill" VerticalAlignment="Top" Source="F:\Dhivya\C#\Personal\ChatApplication\CurrentlyWorking-Important\Ping\Ping\images\videochat_logo.png" ToolTip="Video chat"/>
<Image MouseDown="img_Myfolder_MouseDown_1" Height="40" Width="40" Name="img_Myfolder" Stretch="Fill" Source="F:\Dhivya\C#\Personal\ChatApplication\CurrentlyWorking-Important\Ping\Ping\images\myfolder_logo.png" Margin="329,89,41,411" ToolTip="View chat history" />
<Border BorderBrush="#FF87A4DB" BorderThickness="1" HorizontalAlignment="Left" Margin="10,18,0,367" Name="border_Userdetails" Width="378" CornerRadius="2" />
</Grid>
Am having a set of labels for the online users.So when i double click any label i ll do the following
private void Label_MouseDoubleClick_1(object sender, MouseButtonEventArgs e)
{
Label selectedLabel = (Label)sender;
TabItem existingTab = tabcontrol_Chatwindow.Items.OfType<TabItem>().SingleOrDefault(n => n.Name == selectedLabel.Content);
if (tabcontrol_Chatwindow.Items.Contains(existingTab))
{
tabcontrol_Chatwindow.SelectedItem = existingTab;
}
else
{
TabItem newTab = new TabItem();
newTab.Name = selectedLabel.Content.ToString();
TabHeader header = new TabHeader();
header.userName.Content = selectedLabel.Content;
newTab.Header = header;
//newTab.Header = selectedLabel.Content;
newTab.Content = new NewChatWindow();
tabcontrol_Chatwindow.Items.Add(newTab);
tabcontrol_Chatwindow.SelectedItem = newTab;
}
}

Try using the below code, in which you can find the Window hosting your Usercontrol using Window parentWindow = Window.GetWindow(this);
Dispatcher.BeginInvoke((Action)(() =>
{
string name = todisplayChat.GetValue<string>("FromMessenger");
string msg = todisplayChat.GetValue<string>("ChatSent");
NewChatWindow childWindow = this as NewChatWindow;
MainChatWindow parentWindow = Window.GetWindow(this) as MainChatWindow;
TabControl tabcontrolHome = parentWindow.tabcontrol_Chatwindow;
TabItem existingTab = tabcontrolHome.Items.OfType<TabItem>().SingleOrDefault(n => n.Name == name);
childWindow = (NewChatWindow)existingTab.Content;
childWindow.richtxtbox_chatwindow.AppendText(Environment.NewLine + name + " : " + msg);
}));

Problem with refreshing Data c#

My problem is first I'm downladin xml file from server like this:
private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e)
{
//pobieranie danych z pliku xml znajdujacego sie na serwerze
WebClient client = new WebClient();
client.DownloadStringCompleted += HttpsCompleted;
client.DownloadStringAsync(new Uri("Myurl/baza.xml"));
}
private void HttpsCompleted(object sender, DownloadStringCompletedEventArgs e)
{
if (e.Error == null)
{
XDocument xdoc3 = XDocument.Parse(e.Result, LoadOptions.None);
var data = from query in xdoc3.Descendants("Item")
select new Item
{
name = (string)query.Element("name"),
prise = (int)query.Element("prise"),
howmany = (int)query.Element("howmany")
};
items_listBox.ItemsSource = data;
status_textBlock.Text = "Data ok";
}
else {
status_textBlock.Text = "Fail";
kup_button.Visibility = 0;
}
Then i'v made a refresh button, and add function to it, basicly the same code:
private void button1_Click(object sendera, RoutedEventArgs a)
{
WebClient client2 = new WebClient();
client2.DownloadStringCompleted += HttpsCompleteda;
client2.DownloadStringAsync(new Uri(Myurl/baza.xml"));
}
private void HttpsCompleteda(object sendera, DownloadStringCompletedEventArgs a)
{
#region server_ok
if (a.Error == null
{
#region refresh
XDocument xdoca = XDocument.Parse(a.Result, LoadOptions.None);
var new_data = from query in xdoca.Descendants("Item")
select new Item
{
name = (string)query.Element("name"),
prise = (int)query.Element("prise"),
howmany = (int)query.Element("howmany")
};
items_listBox.ItemsSource = new_data;
}
After laod first xml, it (xml file) is chenged(i can see via my web browser) but when i refresh it looks steel the same in
items_listBox.ItemsSource
any ideas? thanks for help
xaml code
x:Class="Sklep.Page1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="{StaticResource PhoneFontSizeNormal}"
Foreground="{StaticResource PhoneForegroundBrush}"
SupportedOrientations="Portrait" Orientation="Portrait"
mc:Ignorable="d" d:DesignHeight="768" d:DesignWidth="480"
shell:SystemTray.IsVisible="True" Loaded="PhoneApplicationPage_Loaded">
<!--LayoutRoot is the root grid where all page content is placed-->
<Grid x:Name="LayoutRoot" Background="Transparent">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!--TitlePanel contains the name of the application and page title-->
<StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
<TextBlock x:Name="ApplicationTitle" Text="Sklep" Style="{StaticResource PhoneTextNormalStyle}"/>
<TextBlock x:Name="PageTitle" Text="Sklep" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}" Height="49" Width="456" FontSize="30" />
</StackPanel>
<!--ContentPanel - place additional content here-->
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<Button Content="zamow" Height="70" HorizontalAlignment="Left" Margin="-12,474,0,0" Name="kup_button" VerticalAlignment="Top" Width="480" Click="kup_button_Click" />
<TextBlock HorizontalAlignment="Left" Margin="230,550,0,74" Name="textBlock1" Text="Ilość sztuk" Width="190" />
<TextBox Height="57" HorizontalAlignment="Left" Margin="0,536,0,0" Name="order_textBox" Text="1" VerticalAlignment="Top" Width="224" TextAlignment="Right" FontSize="18" />
<CheckBox Content="zapłacone" Height="86" HorizontalAlignment="Left" Margin="171,568,0,0" Name="pay_box" VerticalAlignment="Top" Width="261" />
<ListBox x:Name="items_listBox" MinHeight="200" MinWidth="300" Margin="6,62,6,174" MaxHeight="500">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Margin="10" >
<TextBlock Text="{Binding name}"/>
<TextBlock Text="{Binding prise}"/>
<TextBlock Text="{Binding howmany}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<TextBlock Height="53" HorizontalAlignment="Left" Margin="1,3,0,0" Name="status_textBlock" Text="" VerticalAlignment="Top" Width="449" TextAlignment="Center" />
<Button Content="Odswież" Height="103" HorizontalAlignment="Left" Margin="339,545,0,0" Name="button1" VerticalAlignment="Top" Width="114" FontSize="15" Click="button1_Click" />
</Grid>
</Grid>

The request will be cached by the WebClient.
The easiest solution is to make the request look like a different one by adding something unique to the query string.
client.DownloadStringAsync(new Uri("Myurl/baza.xml?rand=" + Guid.NewGuid()));

Your problem seems more to be a data binding problem than about a web service call. You should give your XAML code.

I've solved it using
static public WebClient public_webclient