Creating a scrolling grid of images using WPF and XAML - c#

I currently have the following XAML code but when I run my app, the ScrollBars appear but I am unable to scroll through the list of images (scrollbar doesn't work).
<Window x:Class="WPFMediaManager.MoviePanel"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MoviePanel" Height="1024" Width="1473.254" WindowStartupLocation="CenterScreen">
<Window.Resources>
<DataTemplate x:Key="ItemTemplate">
<WrapPanel>
<Image Width="200" Height="300" Stretch="Fill" Source="{Binding}"/>
<TextBlock Text="{Binding}"/>
</WrapPanel>
</DataTemplate>
</Window.Resources>
<Grid x:Name="movie_grid">
<ListView Grid.Row="4" Name ="MovieListView" ItemTemplate="{StaticResource ItemTemplate}" ItemsSource="{Binding Path = movie_posters_list}">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<UniformGrid Columns="5" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
<TextBlock Name="SampleTextBlock" Text="{Binding Path=movie_names}" DataContext="{StaticResource ItemTemplate}"/>
</Grid>
</Window>
I'm not sure what is causing this issue and whether I'm using the appropriate containers to house the images.
My goal is something like the following layout:
C# Code behind:
namespace WPFMediaManager {
/// <summary>
/// Interaction logic for MoviePanel.xaml
/// </summary>
public partial class MoviePanel : Window {
public MoviePanel() {
InitializeComponent();
}
List<ImageSource> movie_posters_list = new List<ImageSource>();
List<String> movie_names = new List<String>();
String regex_pattern = #"\\([\w ]+).(?:jpg|png)$";
public void LoadImages() {
//Image current_image;
String movie_poster_path = #"C:\Users\Vax\Desktop\movie_posters";
List<String> filenames = new List<String>(System.IO.Directory.EnumerateFiles(movie_poster_path, "*.jpg"));
foreach (String filename in filenames) {
this.movie_posters_list.Add(new BitmapImage(new Uri(filename)));
Console.WriteLine("filename " + filename);
Match regex_match = Regex.Match(filename.Trim(), regex_pattern);
String matched_movie_name = regex_match.Groups[1].Value;
this.movie_names.Add(matched_movie_name);
Console.WriteLine("Movie Name: " + matched_movie_name);
}
MovieListView.ItemsSource = movie_posters_list;
}
}
}
Edit: I tried the method outlined by #XAML Lover but I don't get the images appearing at all anymore. I'm not sure whether this is a data binding issue.

The TextBlock is hiding the whole ListView, which is blocking the user input. Look at the modified XAML,
<Grid x:Name="movie_grid">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition />
</Grid.RowDefinitions>
<ListView Grid.Row="1"
Name="MovieListView"
ItemTemplate="{StaticResource ItemTemplate}"
ItemsSource="{Binding Path = movie_posters_list}">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<UniformGrid Columns="5" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
<TextBlock Name="SampleTextBlock"
Text="{Binding Path=movie_names}"
DataContext="{StaticResource ItemTemplate}" />
</Grid>

Put your xaml of displaying the pictures in a grid then put that grid inside scrollviewer control and set the desired orientation and alignments and you will get the solution.
<ScrollViewer orientation="" VerticleAllignment="" HorizontalAllignment="">
<Grid>
Place your xaml here...
</Grid>
</ScrollViewer>

Related

Create multiple DataGrids in WPF dynamically

I am trying to dynamically create DataGrids in WPF, one below the other in a Grid. the problem is that I don't even know where to start, I saw that it could be done through code but I would like to use XAML correctly.
void PopulateDatagridSQL(string Data, string index, string TabName)
{
try
{
Data = Data.Replace((Char)6, (Char)124);
List<DataTable> Results = new List<DataTable>();
Results = JsonConvert.DeserializeObject<List<DataTable>>(Data);
foreach (SQLWindow SingleSQLWindows in StaticVar.MySQLWindows)
{
if (SingleSQLWindows.MyINDEX == index)
{
SingleSQLWindows.Dispatcher.Invoke(new Action(() =>
{
foreach (TabItem item in SingleSQLWindows._tabItems)
{
if (item.Name == TabName)
{
//create multiple datagrids up to results.count
((SQLPage)((Frame)item.Content).Content).DataGrid1.ItemsSource = Results[0].DefaultView;//foreach
((SQLPage)((Frame)item.Content).Content).TxtSqlLog.Text = "Records in Datagrid: " + Results[0].Rows.Count;//foreach
}
}
}));
}
}
}
catch (Exception asd)
{
foreach (SQLWindow SingleSQLWindows in StaticVar.MySQLWindows)
{
if (SingleSQLWindows.MyINDEX == index)
{
SingleSQLWindows.Dispatcher.Invoke(new Action(() =>
{
foreach (TabItem item in SingleSQLWindows._tabItems)
{
if (item.Name == TabName)
{
((SQLPage)((Frame)item.Content).Content).TxtSqlLog.Text = "Error in $SqlResponse";
}
}
}));
}
}
}
}
In this function I receive a list of DataTables and for each DataTable I have to create a DataGrid.
<Page x:Class="Emergency_APP_Server_WPF.Forms.SQLPage"
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:local="clr-namespace:Emergency_APP_Server_WPF.Forms"
mc:Ignorable="d" x:Name="SQLPageXaml" Loaded="SQLPage_Loaded"
d:DesignHeight="450" d:DesignWidth="800"
Title="SQLPage" >
<Grid>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" MinHeight="100"></RowDefinition>
<RowDefinition Height="0"></RowDefinition>
<RowDefinition Height="*" MinHeight="150"></RowDefinition>
<RowDefinition Height="35"></RowDefinition>
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition Width="70"></ColumnDefinition>
</Grid.ColumnDefinitions>
<avalonEdit:TextEditor Grid.Column="0" Background="White"
xmlns:avalonEdit="http://icsharpcode.net/sharpdevelop/avalonedit"
Name="MyAvalonEdit" FontFamily="Consolas"
FontSize="11pt" Margin="10,10,10,10" ShowLineNumbers="True"
LineNumbersForeground="Gray" ScrollViewer.VerticalScrollBarVisibility="Auto"
ScrollViewer.HorizontalScrollBarVisibility="Auto" KeyUp="MyAvalonEdit_KeyUp"/>
<Button Grid.Column="1" x:Name="BtnSendSQL" Margin="0,10,10,10" Click="BtnSendSQL_Click">
<StackPanel>
<Image Height="25" Source="..//Resources/send.png"></Image>
<TextBlock Margin="0,10,0,0" VerticalAlignment="Top" Foreground="White" Text="SendSQL"></TextBlock>
</StackPanel>
</Button>
</Grid>
<GridSplitter Margin="0,-10,0,0" Grid.Row="1" HorizontalAlignment="Stretch" Background="Transparent" ResizeBehavior="PreviousAndNext">
</GridSplitter>
<DataGrid Grid.Row="2" x:Name="DataGrid1" RowStyle="{StaticResource DataGridRowSql}" Style="{StaticResource DataGridStyleSQL}" >
<DataGrid.CommandBindings>
<CommandBinding Command="Copy" Executed="CommandBinding_Executed"></CommandBinding>
</DataGrid.CommandBindings>
<DataGrid.InputBindings>
<KeyBinding Key="C" Modifiers="Ctrl" Command="Copy"></KeyBinding>
</DataGrid.InputBindings>
</DataGrid>
<TextBlock TextAlignment="Center" TextWrapping="Wrap" VerticalAlignment="Bottom" Grid.Row="3" x:Name="TxtSqlLog" Text="Wait For Commands..."
FontSize="14" FontFamily="Consolas" Foreground="White"></TextBlock>
</Grid>
</Grid>
I do not know the exact layout where you want to put all the DataGrids, so I just assume you want to place them in row 2 of your Grid. As you want to stack them, you can use an ItemsControl in a ScrollViewer. The latter is just there, so you can scroll through the DataGrids in case the page is too small to display them all. So this is the basic layout for the solutions below.
<Grid>
<Grid.RowDefinitions>
<!-- ...your row definitions. -->
</Grid.RowDefinitions>
<!-- ...your other controls. -->
<ScrollViewer Grid.Row="2">
<ItemsControl/>
</ScrollViewer>
</Grid>
Code-behind solution
In code-behind, you need to access the ItemsControl, so assign it a name.
<ItemsControl x:Name="DataGridContainer"/>
Then just create DataGrids in a loop from your DataTable list.
foreach (var dataTable in Results)
{
var dataGrid = new DataGrid { ItemsSource = dataTable.DefaultView };
DataGridContainer.Items.Add(dataGrid);
};
By the way, in this scenario, you could also use a StackPanel instead of an ItemsControl.
MVVM solution
You can create a property in your view model that exposes the default views of your DataTables.
public ObservableCollection<DataView> DataViews { get; }
Make sure you instantiate the collection in the constructor or implement INotifyPropertyChanged, so that the collection is available in XAML. Then bind the ItemsControl to this collection.
<ItemsControl ItemsSource="{Binding DataViews}"/>
Next create a DataTemplate for the DataView type. As each data view in the bound collection represents a data table that should be displayed as a DataGrid, it would look like this.
<DataTemplate DataType="{x:Type data:DataView}">
<DataGrid ItemsSource="{Binding}"/>
</DataTemplate>
Then you have to assign this data template as ItemTemplate in the ItemsControl. I just inline it here, but you can also put it in any ResourceDictionary and reference it via StaticResource.
<ItemsControl ItemsSource="{Binding DataViews}">
<ItemsControl.ItemTemplate>
<DataTemplate DataType="{x:Type data:DataView}">
<DataGrid ItemsSource="{Binding}"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Now, you just have to add the default views to the DataViews collection. As this collection is an ObservableCollection, it will notify the ItemsControl to update on each add.
foreach (var dataTable in Results)
{
DataViews.Add(dataTable.DefaultView);
};
As an item is added, the ItemsControl will get notified and creates an item using the DataTemplate.
I recommend you to use the MVVM solution, as it separates the presentation from your data and is much easier to realize and customization of the DataGrids via the DataTemplate is much easier, convenient and maintainable in XAML.
<Page x:Class="Emergency_APP_Server_WPF.Forms.SQLPage"
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:z="clr-namespace:System.Data;assembly=System.Data"
xmlns:local="clr-namespace:Emergency_APP_Server_WPF.Forms"
mc:Ignorable="d" x:Name="SQLPageXaml" Loaded="SQLPage_Loaded"
d:DesignHeight="450" d:DesignWidth="800"
Title="SQLPage" >
<Grid>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" MinHeight="100"></RowDefinition>
<RowDefinition Height="0"></RowDefinition>
<RowDefinition Height="*" MinHeight="150"></RowDefinition>
<RowDefinition Height="35"></RowDefinition>
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition Width="70"></ColumnDefinition>
</Grid.ColumnDefinitions>
<avalonEdit:TextEditor Grid.Column="0" Background="White"
xmlns:avalonEdit="http://icsharpcode.net/sharpdevelop/avalonedit"
Name="MyAvalonEdit" FontFamily="Consolas"
FontSize="11pt" Margin="10,10,10,10" ShowLineNumbers="True"
LineNumbersForeground="Gray" ScrollViewer.VerticalScrollBarVisibility="Auto"
ScrollViewer.HorizontalScrollBarVisibility="Auto" KeyUp="MyAvalonEdit_KeyUp"/>
<Button Grid.Column="1" x:Name="BtnSendSQL" Margin="0,10,10,10" Click="BtnSendSQL_Click">
<StackPanel>
<Image Height="25" Source="..//Resources/send.png"></Image>
<TextBlock Margin="0,10,0,0" VerticalAlignment="Top" Foreground="White" Text="SendSQL"></TextBlock>
</StackPanel>
</Button>
</Grid>
<GridSplitter Margin="0,-10,0,0" Grid.Row="1" HorizontalAlignment="Stretch" Background="Transparent" ResizeBehavior="PreviousAndNext">
</GridSplitter>
<ScrollViewer Grid.Row="2">
<ItemsControl ItemsSource="{Binding DataViews}">
<ItemsControl.ItemTemplate>
<DataTemplate DataType="{x:Type z:DataView}">
<DataGrid RowStyle="{StaticResource DataGridRowSql}" Style="{StaticResource DataGridStyleSQL}" ItemsSource="{Binding}">
<DataGrid.CommandBindings>
<CommandBinding Command="Copy" Executed="CommandBinding_Executed"></CommandBinding>
</DataGrid.CommandBindings>
<DataGrid.InputBindings>
<KeyBinding Key="C" Modifiers="Ctrl" Command="Copy"></KeyBinding>
</DataGrid.InputBindings>
</DataGrid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</ScrollViewer>
<TextBlock TextAlignment="Center" TextWrapping="Wrap" VerticalAlignment="Bottom" Grid.Row="3" x:Name="TxtSqlLog" Text="Wait For Commands..."
FontSize="14" FontFamily="Consolas" Foreground="White"></TextBlock>
</Grid>
</Grid>
public ObservableCollection<DataView> _DataViews = new ObservableCollection<DataView>();
public ObservableCollection<DataView> DataViews
{
get
{
return _DataViews;
}
set
{
_DataViews = value;
OnPropertyChanged();
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged([CallerMemberName] string Param = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(Param));
}
foreach (SQLWindow SingleSQLWindows in StaticVar.MySQLWindows)
{
if (SingleSQLWindows.MyINDEX == index)
{
SingleSQLWindows.Dispatcher.Invoke(new Action(() =>
{
foreach (TabItem item in SingleSQLWindows._tabItems)
{
if (item.Name == TabName)
{
foreach (DataTable itemTable in Results)
{
//SingleSQLWindows.DataViews.Add(itemTable.DefaultView);
////create more datagrid while results.count
///
((SQLPage)((Frame)item.Content).Content).DataViews.Add(itemTable.DefaultView);
//((SQLPage)((Frame)item.Content).Content).TxtSqlLog.Text = "Records in Datagrid: " + Results[0].Rows.Count;//foreach
}
}
}
}));
}
}
the visual studio does not report any errors but the scrollviewer remains empty, I cannot understand why

WPF ItemsControl elements - Resize content based on the window size (Anchoring)

im working with wpf and i have the problem that i want to bind a collection to an element which resize its content based on the window size.
To make it more clear a little example:
With static behaviour i would do something like that.
<Grid Margin="10,10,10,10">
<Grid.RowDefinitions>
<RowDefinition Height="50*"/>
<RowDefinition Height="50*"/>
<RowDefinition Height="50*"/>
<RowDefinition Height="50*"/>
</Grid.RowDefinitions>
<Button Grid.Row="0"></Button>
<Button Grid.Row="1"></Button>
<Button Grid.Row="2"></Button>
<Button Grid.Row="3"></Button>
</Grid>
In that case all the Buttons would grow/shrink with the window.
But now i want to have it more dynamic.
I have an ObservableCollection which contains all the elements to be added (dynamic amount).
For the first implementation ive added all the elements to a StackPanel. But the controls within the StackPanel dosent resize so that i think about using a grid instead.
Actual solution:
<Window.Resources>
<DataTemplate DataType="{x:Type local:OwnObject}">
<Button DataContext="{Binding}" Content="{Binding Text}" Margin="0,0,0,0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
</DataTemplate>
</Window.Resources>
<Grid>
<ItemsControl ItemsSource="{Binding SubItems}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel x:Name="stackPanel" Margin="0,0,0,0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</Grid>
How is it possible to use the ItemsControl to generate one row for each element and add it to that row? Other solutions to deal tith the problem are also welcome.
You can use UniformGrid as ItemsPanelTemplate cause it's a grid where all the cells in the grid have the same size. So the code will look like that.
<ItemsControl Name="icTest" VerticalContentAlignment="Stretch">
<ItemsControl.ItemTemplate>
<DataTemplate DataType="{x:Type local:OwnObject}">
<DockPanel Margin="0">
<Button Content="{Binding Text}" Margin="0,0,0,0"
HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/>
</DockPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<UniformGrid Columns="1" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
In code behind it's looks like that.
public class OwnObject : INotifyPropertyChanged
{
private string _text;
public string Text
{
get { return _text; }
set { _text = value; NotifyPropertyChanged( "Text" ); }
}
...
}
...
ObservableCollection<OwnObject> objects = new ObservableCollection<OwnObject>();
objects.Add( new OwnObject() { Text = "first" } );
objects.Add( new OwnObject() { Text = "second" } );
objects.Add( new OwnObject() { Text = "third" } );
icTest.ItemsSource = objects;

How do I make the Expander Header change along with the List item as typing in field occurs?

How do I make the Expander Header change along with the ListBox item as typing in field occurs?
* I just attempted to post this with an image, but this site does not allow me to post an image until I have a reputation greater than 10. The image is simply a window capture of the running WPF program (source below) where the [New] button was clicked once, "John Henry Doe" entered into the Name field and "123-4567" entered into the Phone field, then in bold red "1) As I type here" with arrows pointing to the Name and Phone fields, then in bold red "2) This changes" with arrow pointing to the "John Henry Doe: 123-4567" item in the ListBox, then in bold red "3) But this does not change" with an arrow pointing to "New Contact" of the Expander's Header. *
As can (if I was allowed to post the image) be seen in the image above, as the user types into the Name or Phone field, the ListBox Item changes. It changes because I do a .Refresh() on the KeyUp event. However, the Header of the Expander should be changing at the same time. There is no .Refresh() for that as far as I know. I want the Expander's Header to update as the ListBox's Item does, that is, while the user is typing.
The ListBox's DataContext is an observable collection of the class Contact. The Contact class has a property called ListString with a get that returns the result of the method ListItem(). The ListBox's ItemTemplate simply binds to the ListString property. The Expander's Header is bound to ListBox's SelectedItem.ListString and currently is only updated when selecting different ListBox items. I need it to update as typing occurs.
Below is the XAML and C# code behind code. The controls to the right of the ListBox are invisible until an entry is selected in the ListBox. The [New] button inserts a new item into the ListBox and selects it, thereby casing the controls to the right to appear and focus given to the Name field. As you type into the Name field and/or the Phone field, the corresponding item in the ListBox will update, but not the Expander's Header. That does not update until you select another item in the ListBox. I want it to update at the same time the ListBox item updates. How do I do that?
<Window x:Class="Binding_List_Expander_04.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Binding List Expander 04"
Height="350"
Width="530">
<Window.Resources>
</Window.Resources>
<Grid>
<StackPanel Orientation="Horizontal" Margin="3">
<StackPanel Orientation="Vertical" Margin="3">
<ListBox Name="ContactList"
ItemsSource="{Binding}"
Width="166"
Height="270"
Margin="0,0,0,3">
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=ListString}" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Button Name="NewItem"
Content="New"
Click="Event_NewContact_Click"
Height="23"
Width="75" />
</StackPanel>
<StackPanel Orientation="Vertical">
<StackPanel.Resources>
<Style TargetType="ScrollViewer">
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=ContactList, Path=SelectedIndex}" Value="-1">
<Setter Property="Opacity" Value="0" />
</DataTrigger>
</Style.Triggers>
</Style>
</StackPanel.Resources>
<ScrollViewer Height="302">
<StackPanel Orientation="Vertical">
<Expander Name="ContactExpander">
<Expander.HeaderTemplate>
<DataTemplate>
<TextBlock Text="{Binding ElementName=ContactList, Path=SelectedItem.ListString}" />
</DataTemplate>
</Expander.HeaderTemplate>
<StackPanel Margin="21,0,0,0"
Orientation="Vertical">
<Grid Margin="3"
TextBoxBase.TextChanged="Event_ContactName_TextChanged">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="3" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto" />
<ColumnDefinition Width="3" />
<ColumnDefinition Width="250" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0"
Grid.Column="0"
Text="Name:" />
<TextBox Grid.Row="0"
Grid.Column="2"
Name="ContactName"
Text="{Binding ElementName=ContactList, Path=SelectedItem.Name, Mode=TwoWay}" />
<TextBlock Grid.Row="2"
Grid.Column="0"
Text="Phone:" />
<TextBox Grid.Row="2"
Grid.Column="2"
Name="ContactPhone"
Text="{Binding ElementName=ContactList, Path=SelectedItem.Phone, Mode=TwoWay}" />
</Grid>
</StackPanel>
</Expander>
<Expander Header="
This is a place holder, there will be
many Expanders following this one."
Margin="0,10,0,0">
<StackPanel>
<TextBlock Text="Data and
Information" FontSize="30" TextAlignment="Center" />
</StackPanel>
</Expander>
<Expander Header="This is another place holder."
Margin="0,10,0,0">
<StackPanel>
<TextBlock Text="Data and
Information" FontSize="30" TextAlignment="Center" />
</StackPanel>
</Expander>
<Expander Header="This is another place holder."
Margin="0,10,0,0">
<StackPanel>
<TextBlock Text="Data and
Information" FontSize="30" TextAlignment="Center" />
</StackPanel>
</Expander>
</StackPanel>
</ScrollViewer>
</StackPanel>
</StackPanel>
</Grid>
</Window>
using System.Windows;
using System.Collections.ObjectModel;
using System.Windows.Threading;
using System.Threading;
using System.Windows.Controls;
namespace Binding_List_Expander_04
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
ObservableCollection<Contact> Contacts = new ObservableCollection<Contact>();
public MainWindow()
{
InitializeComponent();
ContactList.DataContext = Contacts;
}
private void Event_NewContact_Click(object sender, RoutedEventArgs e)
{
Contacts.Insert(0, new Contact());
ContactList.SelectedIndex = 0;
if (ContactExpander.IsExpanded)
SetFocus(ContactName);
else
{
ContactExpander.IsExpanded = true;
SetFocus(ContactName);
}
}
public void SetFocus(UIElement control)
{
control.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle, (ThreadStart)delegate { control.Focus(); });
}
private void Event_ContactName_TextChanged(object sender, TextChangedEventArgs e)
{
var tb = e.Source as TextBox;
Contact C = ContactList.SelectedItem as Contact;
if (tb == ContactName)
C.Name = tb.Text;
else if (tb == ContactPhone)
C.Phone = tb.Text;
ContactList.Items.Refresh();
}
}
public class Contact
{
public string Name { get; set; }
public string Phone { get; set; }
public string ListString { get { return ListItem(); } } // See comments in ListItem() below.
public Contact()
{
Name = string.Empty;
Phone = string.Empty;
}
private string ListItem()
{/*
* This is a simplified version, the actual version is complicated and cannot be templatized.
* Please, do not suggest templitazing this. I know this simple version can be templitazed,
* but the actual version cannot be templatized. I need to know how to make this work as it
* currently is.
*/
if ((Name + Phone).Trim().Length == 0)
return "<New Contact>";
else
{
string li = Name.Trim();
if (li.Length != 0 && Phone.Trim().Length != 0) li += ": ";
return li + Phone.Trim();
}
}
}
}
Thanks for you help.

NullPointerException after going back in a NavigationWindow

thats my navigation window
<NavigationWindow x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="800" Width="600" Source="Page1.xaml">
thats my page1
<Page x:Class="WpfApplication1.Page1"
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="600" d:DesignWidth="800"
Title="Page1" Name="IndexPage">
<ListView Name="myListView" ItemsSource="{Binding ElementName=IndexPage, Path=SeriesCollection}" ScrollViewer.HorizontalScrollBarVisibility="Disabled" IsSynchronizedWithCurrentItem="True" SelectionChanged="handleSelected">
<ListView.ItemsPanel >
<ItemsPanelTemplate>
<WrapPanel>
</WrapPanel>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel >
<Image Width="214" Height="317" Source="{Binding Image}"/>
<Label Content="{Binding Name}" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
Page 2 is just en empty skeleton
code behind
namespace WpfApplication1
{
/// <summary>
/// Interaktionslogik für Page1.xaml
/// </summary>
public partial class Page1 : Page
{
private ObservableCollection<Series> _series =
new ObservableCollection<Series>();
public ObservableCollection<Series> SeriesCollection
{
get { return _series; }
}
public Page1()
{
InitializeComponent();
DirectoryInfo baseDir = new DirectoryInfo(#"C:\Serien");
DirectoryInfo[] dirs = baseDir.GetDirectories();
foreach (DirectoryInfo dir in dirs)
{
Series serie = new Series(dir);
Console.WriteLine("adding " + serie.Name);
_series.Add(serie);
}
Console.WriteLine(_series.Count);
}
public void handleSelected(object sender, RoutedEventArgs args)
{
Series currentSerie = (Series) myListView.Items.CurrentItem;
Page2 page = new Page2();
this.NavigationService.Navigate(page);
Console.WriteLine(currentSerie.Name);
Console.WriteLine(currentSerie.GetType());
Console.WriteLine(currentSerie.ToString());
}
}
}
so i click on an item to trigger the SelectionChanged Event to handle it in SelectionChanged where i navigate to page2 , so far so good.
then i use the back button from the navigation window and get stuck with an NullpointerException at
this.NavigationService.Navigate(page);
i dont even know why this method is triggered. So obviosly i am doing something stupid. Pls tell me what it is. Thanks for your time and affort.
The problem here is that you handle the wrong event. I assume that you want to open Page2 by clicking a ListViewItem. Therefore you should use mouse events instead of SelectionChanged.
For example, you can subscribe to StackPanel MouseDown event in your DataTemplate:
<DataTemplate>
<StackPanel Background="Transparent"
MouseDown="StackPanel_MouseDown">
<Image Width="214" Height="317" Source="{Binding Image}"/>
<Label Content="{Binding Name}"/>
</StackPanel>
</DataTemplate>
You can access clicked Series using the following:
private void StackPanel_MouseDown(object sender, MouseButtonEventArgs e)
{
var currentSerie = (Series)((StackPanel)sender).DataContext;
...
}
UPD If you need a real click, you may use a trick like this:
<DataTemplate>
<Button Click="Button_Click">
<Button.Template>
<ControlTemplate TargetType="Button">
<ContentPresenter/>
</ControlTemplate>
</Button.Template>
<StackPanel Background="Transparent">
<Image Width="214" Height="317" Source="{Binding Image}"/>
<Label Content="{Binding Name}"/>
</StackPanel>
</Button>
</DataTemplate>
We use a Button like a view-model which is able to handle clicks.

Pivot Control - issue with data binding

I've checked various examples of Pivots and think my implementation should work but it's having an issue.
Here is the XAML:
<controls:Pivot Title="Results" ItemsSource="{Binding baskets}">
<controls:Pivot.HeaderTemplate>
<DataTemplate>
<Grid x:Name="grid">
<TextBlock Text="{Binding basketName}" />
</Grid>
</DataTemplate>
</controls:Pivot.HeaderTemplate>
<controls:Pivot.ItemTemplate>
<DataTemplate>
<Grid>
<StackPanel Orientation="Vertical">
<TextBlock TextWrapping="Wrap" Text="{Binding basketItems.Count}"/>
</StackPanel>
</Grid>
</DataTemplate>
</controls:Pivot.ItemTemplate>
</controls:Pivot>
and the code-behind:
public ObservableCollection<Basket> baskets = new ObservableCollection<Basket>();
public pivotPage()
{
InitializeComponent();
//for testing purposes
baskets.Add(new Basket());
baskets.Add(new Basket());
}
The page renders blank, what am I doing wrong?
There is no indication in your code that you have set your DataContext. Try the following:
public ObservableCollection<Basket> baskets = new ObservableCollection<Basket>();
public pivotPage()
{
InitializeComponent();
this.DataContext = baskets;
//for testing purposes
baskets.Add(new Basket());
baskets.Add(new Basket());
}

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