WPF Combobox event does not fire (using MVVM and Expression.Blend) - c#

I am really fairly new to WPF and have just wrapped my head around MVVM / Expression.Blend.
I am trying to use the Combobox "SelectedIndexChanged" event with InvokeCommandAction, binding to a command specified in the ViewModel.
However, the code in the command is never executed (the value myvalue is never updated).
What am I doing wrong here?
XAML:
<UserControl x:Class="GDX.UI.Views.AnalyseView"
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:i1="http://schemas.microsoft.com/xaml/behaviors"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
xmlns:local="clr-namespace:GDX.UI.Views"
mc:Ignorable="d"
Height="720" Width="1210">
<Control.Resources>
<ResourceDictionary Source="pack://application:,,,/GDX.UI;component/ResourceDictionary/ResourceDictionary.xaml"/>
</Control.Resources>
<materialDesign:Card Margin="15,15,15,15" Grid.Column ="0" Grid.Row="0" Grid.RowSpan="6" Grid.ColumnSpan="2">
<ScrollViewer Grid.Row="0" Grid.RowSpan="5" Grid.Column="0" Grid.ColumnSpan="2" VerticalScrollBarVisibility="Hidden">
<ItemsControl ItemsSource="{Binding buildingComponents}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical" Margin="10">
<TextBlock Margin="10" Text="{Binding Path=UIName}" FontWeight="Bold"/>
<ComboBox
ItemsSource="{Binding Path=ConstructionOptions}"
SelectedItem="{Binding Path=Construction}"
HorizontalAlignment="Center"
Style="{StaticResource MaterialDesignOutlinedComboBox}"
Width="256"
Height="50"
BorderBrush="Red"
materialDesign:HintAssist.Hint="Baukonstruktion">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectedIndexChanged">
<i:InvokeCommandAction Command="{Binding SetBuildingComponentConstruction}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</ComboBox>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</ScrollViewer>
</materialDesign:Card>
ViewModel:
using GDX.IO.Schemas;
using GDX.IO.Statics;
using GDX.MVVM;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
namespace GDX.ViewModel.ViewModels
{
public class AnalyseViewModel : BaseViewModel
{
public ObservableCollection<BuildingComponent> buildingComponents { get; set; }
public double myvalue { get; set; }
public ICommand SetBuildingComponentConstruction { get; set; }
public AnalyseViewModel()
{
this.buildingComponents = new ObservableCollection<BuildingComponent>();
if (Building.BuildingComponents.Count != 0) //if contains elements
{
foreach (BuildingComponent bcomp in Building.BuildingComponents)
{
this.buildingComponents.Add(bcomp);
}
}
this.SetBuildingComponentConstruction = new RelayCommand(this.setBuildingComponentConstruction);
this.myvalue = 0;
}
public void setBuildingComponentConstruction()
{
myvalue += 1;
}
}
}

Looks like the SetBuildingComponentConstruction method is defined on AnalyseViewModel, but where you are binding in the itemstemplate the datacontext would be a BuildingComponent. You may have to "walk" up to the datacontext of your UserControl.
How do I use WPF bindings with RelativeSource?
Looking at the XAML Binding Failures tab in VS while debugging may also provide you with some direction.
Try
Command="{Binding DataContext.SetBuildingComponentConstruction,
RelativeSource={RelativeSource AncestorType=ComboBox}}"

Related

Bind controls to a stackpanel in winui3

i'm making in a music player program, and now I need to add a page to show the playlist's detail, such as the musics and the music's artists in the playlist.I'm going to make some musics' card and add them to a stackpanel.
I have achieved this by getting this panel object and calling its add function, but can I achieve it through data binding?
This is the way i used before
<StackPanel x:Name="PanelMusics" />
PanelMusics.Children.Add(...);
You should try using ListView or ItemsRepeater instead of StackPanel.
This is a simple example how to use ListView with the help of the CommunityToolkit.Mvvm NuGet package.
MusicItem.cs
namespace MusicCardsSample;
public class MusicItem
{
public string Title { get; set; } = string.Empty;
public string Artist { get; set; } = string.Empty;
}
MainPageViewModel.cs
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using System.Collections.ObjectModel;
namespace MusicCardsSample;
// The "CommunityTookit.Mvvm" needs this class to be "partial".
public partial class MainPageViewModel : ObservableObject
{
// The "CommunityTookit.Mvvm" creates
// an UI-interactable property "MusicItems" for you.
[ObservableProperty]
private ObservableCollection<MusicItem> musicItems = new();
// The "CommunityTookit.Mvvm" creates
// an "AddMusicItemCommand" command for you.
[RelayCommand]
private void AddMusicItem(MusicItem item)
{
musicItems.Add(item);
}
}
MainPage.xaml.cs
using Microsoft.UI.Xaml.Controls;
namespace MusicCardsSample;
public sealed partial class MainPage : Page
{
public MainPage()
{
this.InitializeComponent();
}
private MainPageViewModel ViewModel { get; } = new();
}
MainPage.xaml
<Page
x:Class="MusicCardsSample.MainPage"
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:local="using:MusicCardsSample"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
mc:Ignorable="d">
<Grid RowDefinitions="Auto,*">
<StackPanel
Grid.Row="0"
Orientation="Horizontal">
<TextBox
x:Name="TitleTextBlock"
PlaceholderText="Title" />
<TextBox
x:Name="ArtistTextBlock"
PlaceholderText="Artist" />
<Button
Command="{x:Bind ViewModel.AddMusicItemCommand}"
Content="Add">
<Button.CommandParameter>
<local:MusicItem
Title="{x:Bind TitleTextBlock.Text, Mode=OneWay}"
Artist="{x:Bind ArtistTextBlock.Text, Mode=OneWay}" />
</Button.CommandParameter>
</Button>
</StackPanel>
<ListView
Grid.Row="1"
ItemsSource="{x:Bind ViewModel.MusicItems, Mode=OneWay}">
<ListView.ItemTemplate>
<DataTemplate x:DataType="local:MusicItem">
<!--You can design your music cards here.-->
<StackPanel Orientation="Vertical">
<TextBlock
FontSize="9"
Text="{x:Bind Artist}" />
<TextBlock Text="{x:Bind Title}" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
</Page>

Navigate ContentControl from inside a UserControl in MVVM

I'm trying to create a sort of ShellView without using thirdparty frameworks, and I'm doing trying to do it via. ContentControls and UserControls.
I can navigate/switch the UserControls that is showed inside the ContentControls as long as the commands are fired from outside the UserControls, but nothing is happening when I move the code inside a button in a UserControl.
Currently I'm having one MainWindow.XAML, where I have one ContentControl.
This ContentControl is hosting either a LoginWindowUserControl, or a UserWindowUserControl - I want to be able switch the UserControl from within one of the UserControls.
My MainWindow.XAML looks like this:
<Window x:Class="ModelHealthApplication.MainWindow"
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:vms="clr-namespace:ModelHealthApplication.ViewModels"
xmlns:ia="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:views="clr-namespace:ModelHealthApplication.Views.UserControls"
xmlns:local="clr-namespace:ModelHealthApplication"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Window.Resources>
<DataTemplate DataType="{x:Type vms:CurrentWindowUserStateViewModel}">
<views:UserView />
</DataTemplate>
<DataTemplate DataType="{x:Type vms:LoginWindowViewModel}">
<views:LoginView />
</DataTemplate>
<vms:NavigationViewModel x:Key="nVm" />
</Window.Resources>
<ia:Interaction.Triggers>
<ia:EventTrigger EventName="Loaded">
<ia:InvokeCommandAction Command="{Binding Source={StaticResource nVm}, Path=OpenLoginWindowCommand}" />
</ia:EventTrigger>
</ia:Interaction.Triggers>
<Grid DataContext="{StaticResource nVm}">
<DockPanel>
<Button Content="Test" DockPanel.Dock="Left" Command="{Binding OpenUserWindowStateCommand}" />
<ContentControl x:Name="WindowUserState" Content="{Binding CurrentWindowUserState}" />
</DockPanel>
</Grid>
And my UserWindowUserControl looks like this:
<UserControl x:Class="ModelHealthApplication.Views.UserControls.UserView"
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:vms="clr-namespace:ModelHealthApplication.ViewModels"
xmlns:views="clr-namespace:ModelHealthApplication.Views.UserControls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:ModelHealthApplication.Views.UserControls"
mc:Ignorable="d"
d:DesignHeight="450" d:DesignWidth="800">
<UserControl.Resources>
<DataTemplate DataType="{x:Type vms:MyModelsViewModel}">
<views:MyModelsView/>
</DataTemplate>
<DataTemplate DataType="{x:Type vms:MyAccountViewModel}">
<views:MyAccountView />
</DataTemplate>
<vms:NavigationViewModel x:Key="nVm" />
</UserControl.Resources>
<Grid>
<DockPanel DataContext="{StaticResource nVm}">
<Grid DockPanel.Dock="Top" Background="{StaticResource MainBlue}" Height="25">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<StackPanel Orientation="Horizontal" Grid.Column="0">
<Button Content="My Models"
HorizontalAlignment="Center"
Command="{Binding OpenMyModelsCommand}"
Style="{StaticResource NavButtonStyle}"/>
<Button Content="My Account"
HorizontalAlignment="Center"
Command="{Binding OpenMyAccountCommand}"
Style="{StaticResource NavButtonStyle}"
/>
</StackPanel>
<StackPanel Orientation="Horizontal" VerticalAlignment="Center" HorizontalAlignment="Right" Grid.Column="1" Margin="0, 0, 10, 0">
<TextBlock VerticalAlignment="Center" Foreground="White">
<Run Text="Logged in as:" FontWeight="Bold"/>
<Run Text="{Binding LoggedInAs}" d:Text="TestUser" />
</TextBlock>
<TextBlock Margin="20, 0 ,0 ,0" Text="Log Out" VerticalAlignment="Center" TextDecorations="Underline" Foreground="{StaticResource ComplenetarySecondOrange}" Background="{DynamicResource MainBlue}" Cursor="Hand">
<TextBlock.InputBindings>
<MouseBinding Command="{Binding OpenLoginWindowCommand}" MouseAction="LeftClick" />
</TextBlock.InputBindings>
</TextBlock>
</StackPanel>
</Grid>
<ContentControl x:Name="Pages" Content="{Binding SelectedViewModel}" />
</DockPanel>
</Grid>
</UserControl>
When I press the "Log Out" button/textblock I want to navigate back to the login window, but I can only do this from buttons that exist outside the UserControl.
I've read several other post similar to this, but I haven't found a solution that fits my needs - I tried using RelativeSource but without success - maybe someone can see what I'm doing wrong.
I'm using a "NavigationViewModel" to hold the commands which as I mentioned, works fine outside the UserControls:
using ModelHealthApplication.Commands;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
namespace ModelHealthApplication.ViewModels
{
public class NavigationViewModel : INotifyPropertyChanged
{
public ICommand OpenMyModelsCommand { get; set; }
public ICommand OpenMyAccountCommand { get; set; }
public ICommand OpenUserWindowStateCommand { get; set; }
public ICommand OpenLoginWindowCommand { get; set; }
private object currentWindowUserState;
public object CurrentWindowUserState
{
get { return currentWindowUserState; }
set
{
currentWindowUserState = value;
OnPropertyChanged("CurrentWindowUserState");
}
}
private object selectedViewModel;
public object SelectedViewModel
{
get { return selectedViewModel; }
set
{
selectedViewModel = value;
OnPropertyChanged("SelectedViewModel");
}
}
public NavigationViewModel()
{
OpenMyModelsCommand = new OpenMyModelsCommand(this);
OpenMyAccountCommand = new OpenAccountCommand(this);
OpenUserWindowStateCommand = new OpenUserWindowStateCommand(this);
OpenLoginWindowCommand = new OpenLoginWindowCommand(this);
}
public void OpenUserWindowState(object obj)
{
CurrentWindowUserState = new CurrentWindowUserStateViewModel();
}
public void OpenLoginWindow(object obj)
{
CurrentWindowUserState = new LoginWindowViewModel();
}
public void OpenMyModels(object obj)
{
SelectedViewModel = new MyModelsViewModel();
}
public void OpenMyAccount(object obj)
{
SelectedViewModel = new MyAccountViewModel();
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propName));
}
}
}
}
Ended up solving this with a great tutorial from SingletonSean on Youtube.
Posting here if anyone comes across this, and has the same issue.
Singleton Sean MVVM Navigatoin

Display selected listbox items' data in wpf

I'm in search of some help. I've created a very basic MVVM setup. My object is called VNode which has the properties Name,Age,Kids. What I want to happen is when the user selects VNodes on the left, it displays their more in depth data on the right as scene in the image below. I'm not sure how to go about doing this.
image 1: Current
Image 2: Goal
If you don't feel like using the code below to recreate the window you can grab the project solution files from here: DropboxFiles
VNode.cs
namespace WpfApplication1
{
public class VNode
{
public string Name { get; set; }
public int Age { get; set; }
public int Kids { get; set; }
}
}
MainWindow.xaml
<Window x:Class="WpfApplication1.MainWindow"
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:local="clr-namespace:WpfApplication1"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<local:MainViewModel/>
</Window.DataContext>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="8" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<ListBox Grid.Column="0" Background="AliceBlue" ItemsSource="{Binding VNodes}" SelectionMode="Extended">
<ListBox.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="Name: " />
<TextBlock Text="{Binding Name}" FontWeight="Bold" />
</WrapPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<GridSplitter Grid.Column="1" Width="5" HorizontalAlignment="Stretch" />
<ListBox Grid.Column="2" Background="LightBlue" ItemsSource="{Binding VNodes}">
<ListBox.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="{Binding Name}" FontWeight="Bold" />
<TextBlock Text=":" FontWeight="Bold" />
<TextBlock Text=" age:"/>
<TextBlock Text="{Binding Age}" FontWeight="Bold" />
<TextBlock Text=" kids:"/>
<TextBlock Text="{Binding Kids}" FontWeight="Bold" />
</WrapPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Window>
MainViewModel.cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace WpfApplication1
{
public class MainViewModel : ObservableObject
{
private ObservableCollection<VNode> _vnodes;
public ObservableCollection<VNode> VNodes
{
get { return _vnodes; }
set
{
_vnodes = value;
NotifyPropertyChanged("VNodes");
}
}
Random r = new Random();
public MainViewModel()
{
//hard coded data for testing
VNodes = new ObservableCollection<VNode>();
List<string> names = new List<string>() { "Tammy", "Doug", "Jeff", "Greg", "Kris", "Mike", "Joey", "Leslie", "Emily","Tom" };
List<int> ages = new List<int>() { 32, 24, 42, 57, 17, 73, 12, 8, 29, 31 };
for (int i = 0; i < 10; i++)
{
VNode item = new VNode();
int x = r.Next(0,9);
item.Name = names[x];
item.Age = ages[x];
item.Kids = r.Next(1, 5);
VNodes.Add(item);
}
}
}
}
ObservableObject.cs
using System;
using System.ComponentModel;
using System.Runtime.CompilerServices;
namespace WpfApplication1
{
public class ObservableObject : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}
UPDATED
For the sake of example, how about demonstrating if the user just selects a single item in the ListBox on the right, it then displays that selected items more in-depth data on the right as shown in the image below?
There are three and a half answers here. Number one is good general WPF practice that doesn't work in the specific case of ListBox. The second one is a quick and dirty workaround for the problem with ListBox, and the last is the best, because it does nothing in code behind. Least code behind is best code behind.
The first way to do this doesn't require anything of the items you're displaying in the ListBox. They could be strings or integers. If your item type (or types) is a class (or are classes) with a little more meat to it, and you'd like to have each instance know whether it's been selected or not, we'll get to that next.
You need to give your view model another ObservableCollection<VNode> called SelectedVNodes or some such.
private ObservableCollection<VNode> _selectedvnodes;
public ObservableCollection<VNode> SelectedVNodes
{
get { return _selectedvnodes; }
set
{
_selectedvnodes = value;
NotifyPropertyChanged("SelectedVNodes");
}
}
public MainViewModel()
{
VNodes = new ObservableCollection<VNode>();
SelectedVNodes = new ObservableCollection<VNode>();
// ...etc., just as you have it now.
If System.Windows.Controls.ListBox weren't broken, then in your first ListBox, you would bind SelectedItems to that viewmodel property:
<ListBox
Grid.Column="0"
Background="AliceBlue"
ItemsSource="{Binding VNodes}"
SelectedItems="{Binding SelectedVNodes}"
SelectionMode="Extended">
And the control would be in charge of the content of SelectedVNodes. You could also change SelectedVNodes programmatically, and that would update both lists.
But System.Windows.Controls.ListBox is broken, and you can't bind anything to SelectedItems. The simplest workaround is to handle the ListBox's SelectionChanged event and kludge it in the code behind:
XAML:
<ListBox
Grid.Column="0"
Background="AliceBlue"
ItemsSource="{Binding VNodes}"
SelectionMode="Extended"
SelectionChanged="ListBox_SelectionChanged">
C#:
private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListBox lb = sender as ListBox;
MainViewModel vm = DataContext as MainViewModel;
vm.SelectedVNodes.Clear();
foreach (VNode item in lb.SelectedItems)
{
vm.SelectedVNodes.Add(item);
}
}
Then bind ItemsSource in your second ListBox to SelectedVNodes:
<ListBox
Grid.Column="2"
Background="LightBlue"
ItemsSource="{Binding SelectedVNodes}">
And that should do what you want. If you want to be able to update SelectedVNodes programmatically and have the changes reflected in both lists, you'll have to have your codebehind class handle the PropertyChanged event on the viewmodel (set that up in the codebehind's DataContextChanged event), and the CollectionChanged event on viewmodel.SelectedVNodes -- and remember to set the CollectionChanged handler all over again every time SelectedVNodes changes its own value. It gets ugly.
A better long-term solution would be to write an attachment property for ListBox that replaces SelectedItems and works right. But this kludge will at least get you moving for the time being.
Update
Here's a second way of doing it, which OP suggested. Instead of maintaining a selected item collection, we put a flag on each item, and the viewmodel has a filtered version of the main item list that returns only selected items. I'm drawing a blank on how to bind VNode.IsSelected to the IsSelected property on ListBoxItem, so I just did that in the code behind.
VNode.cs:
using System;
namespace WpfApplication1
{
public class VNode
{
public string Name { get; set; }
public int Age { get; set; }
public int Kids { get; set; }
// A more beautiful way to do this would be to write an IVNodeParent
// interface with a single method that its children would call
// when their IsSelected property changed -- thus parents would
// implement that, and they could name their "selected children"
// collection properties anything they like.
public ObservableObject Parent { get; set; }
private bool _isSelected = false;
public bool IsSelected
{
get { return _isSelected; }
set
{
if (value != _isSelected)
{
_isSelected = value;
if (null == Parent)
{
throw new NullReferenceException("VNode.Parent must not be null");
}
Parent.NotifyPropertyChanged("SelectedVNodes");
}
}
}
}
}
MainViewModel.cs:
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace WpfApplication1
{
public class MainViewModel : ObservableObject
{
private ObservableCollection<VNode> _vnodes;
public ObservableCollection<VNode> VNodes
{
get { return _vnodes; }
set
{
_vnodes = value;
NotifyPropertyChanged("VNodes");
NotifyPropertyChanged("SelectedVNodes");
}
}
public IEnumerable<VNode> SelectedVNodes
{
get { return _vnodes.Where(vn => vn.IsSelected); }
}
Random r = new Random();
public MainViewModel()
{
//hard coded data for testing
VNodes = new ObservableCollection<VNode>();
List<string> names = new List<string>() { "Tammy", "Doug", "Jeff", "Greg", "Kris", "Mike", "Joey", "Leslie", "Emily","Tom" };
List<int> ages = new List<int>() { 32, 24, 42, 57, 17, 73, 12, 8, 29, 31 };
for (int i = 0; i < 10; i++)
{
VNode item = new VNode();
int x = r.Next(0,9);
item.Name = names[x];
item.Age = ages[x];
item.Kids = r.Next(1, 5);
item.Parent = this;
VNodes.Add(item);
}
}
}
}
MainWindow.xaml.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
foreach (VNode item in e.RemovedItems)
{
item.IsSelected = false;
}
foreach (VNode item in e.AddedItems)
{
item.IsSelected = true;
}
}
}
}
MainWindow.xaml (partial):
<ListBox
Grid.Column="0"
Background="AliceBlue"
ItemsSource="{Binding VNodes}"
SelectionMode="Extended"
SelectionChanged="ListBox_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="Name: " />
<TextBlock Text="{Binding Name}" FontWeight="Bold" />
</WrapPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<GridSplitter Grid.Column="1" Width="5" HorizontalAlignment="Stretch" />
<ListBox Grid.Column="2" Background="LightBlue" ItemsSource="{Binding SelectedVNodes}">
<ListBox.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="{Binding Name}" FontWeight="Bold" />
<TextBlock Text=":" FontWeight="Bold" />
<TextBlock Text=" age:"/>
<TextBlock Text="{Binding Age}" FontWeight="Bold" />
<TextBlock Text=" kids:"/>
<TextBlock Text="{Binding Kids}" FontWeight="Bold" />
</WrapPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Update 2
And here, finally, is how you do it with binding (thanks to OP for figuring out for me how to bind data item properties to ListBoxItem properties -- I should be able to accept his comment as an answer!):
In MainWindow.xaml, get rid of the SelectionCanged event (yay!), and set a Style to do the binding only on the items in the first ListBox. In the second ListBox, that binding will create problems which I'll leave to somebody else to resolve; I have a guess that it might be fixable by fiddling with the order of notifications and assignments in VNode.IsSelected.set, but I could be wildly wrong about that. Anyway the binding serves no purpose in the second ListBox so there's no reason to have it there.
<ListBox
Grid.Column="0"
Background="AliceBlue"
ItemsSource="{Binding VNodes}"
SelectionMode="Extended"
>
<ListBox.Resources>
<Style TargetType="{x:Type ListBoxItem}" BasedOn="{StaticResource {x:Type ListBoxItem}}">
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
</Style>
</ListBox.Resources>
<ListBox.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="Name: " />
<TextBlock Text="{Binding Name}" FontWeight="Bold" />
</WrapPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
...and I removed the event handler method from the codebehind. But you didn't add it at all, because you're smarter than me and you started with this last version of the answer.
In VNode.cs, VNode becomes an ObservableObject so he can advertise his selection status, and he also fires the appropriate notification in IsSelected.set. He still has to fire the change notification for his Parent's SelectedVNodes property, because the second listbox (or any other consumer of SelectedVNodes) needs to know that the set of selected VNodes has changed.
Another way to do that would be to make SelectedVNodes an ObservableCollection again, and have VNode add/remove himself from it when his selected status changes. Then the viewmodel would have to handle CollectionChanged events on that collection, and update the VNode IsSelected properties when they're added to it or removed from it. If you do that, it's very important to keep the if in VNode.IsSelected.set, to prevent infinite recursion.
using System;
namespace WpfApplication1
{
public class VNode : ObservableObject
{
public string Name { get; set; }
public int Age { get; set; }
public int Kids { get; set; }
public ObservableObject Parent { get; set; }
private bool _isSelected = false;
public bool IsSelected
{
get { return _isSelected; }
set
{
if (value != _isSelected)
{
_isSelected = value;
if (null == Parent)
{
throw new NullReferenceException("VNode.Parent must not be null");
}
Parent.NotifyPropertyChanged("SelectedVNodes");
NotifyPropertyChanged("IsSelected");
}
}
}
}
}
Update 3
OP asks about displaying a single selection in a detail pane. I left the old multi-detail pane in place to demonstrate sharing a template.
That's pretty simple to do, so I elaborated a bit. You could do this only in the XAML, but I threw in a SelectedVNode property in the viewmodel to demonstrate that as well. It's not used for anything, but if you wanted to throw in a command that operated on the selected item (for example), that's how the view model would know which item the user means.
MainViewModel.cs
// Add to MainViewModle class
private VNode _selectedVNode = null;
public VNode SelectedVNode
{
get { return _selectedVNode; }
set
{
if (value != _selectedVNode)
{
_selectedVNode = value;
NotifyPropertyChanged("SelectedVNode");
}
}
}
MainWindow.xaml:
<Window x:Class="WpfApplication1.MainWindow"
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:local="clr-namespace:WpfApplication1"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<SolidColorBrush x:Key="ListBackgroundBrush" Color="Ivory" />
<DataTemplate x:Key="VNodeCardTemplate">
<Grid>
<Border
x:Name="BackgroundBorder"
BorderThickness="1"
BorderBrush="Silver"
CornerRadius="16,6,6,6"
Background="White"
Padding="6"
Margin="4,4,8,8"
>
<Border.Effect>
<DropShadowEffect BlurRadius="2" Opacity="0.25" ShadowDepth="4" />
</Border.Effect>
<Grid
x:Name="ContentGrid"
>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<!-- Each gets half of what's left -->
<ColumnDefinition Width="0.5*" />
<ColumnDefinition Width="0.5*" />
</Grid.ColumnDefinitions>
<Border
Grid.Row="0" Grid.RowSpan="3"
VerticalAlignment="Top"
Grid.Column="0"
BorderBrush="{Binding Path=BorderBrush, ElementName=BackgroundBorder}"
BorderThickness="1"
CornerRadius="9,4,4,4"
Margin="2,2,6,2"
Padding="4"
>
<StackPanel Orientation="Vertical">
<StackPanel.Effect>
<DropShadowEffect BlurRadius="2" Opacity="0.25" ShadowDepth="2" />
</StackPanel.Effect>
<Ellipse
Width="16" Height="16"
Fill="DarkOliveGreen"
Margin="0,0,0,2"
HorizontalAlignment="Center"
/>
<Border
CornerRadius="6,6,2,2"
Background="DarkOliveGreen"
Width="36"
Height="18"
Margin="0"
/>
</StackPanel>
</Border>
<TextBlock Grid.Row="0" Grid.Column="1" Grid.ColumnSpan="2" Text="{Binding Name}" FontWeight="Bold" />
<Separator Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2" Background="{Binding Path=BorderBrush, ElementName=BackgroundBorder}" Margin="0,3,0,3" />
<!--
Mode=OneWay on Run.Text because bindings on that property should default to that, but don't.
And if you bind TwoWay to a property without a setter, it throws an exception.
-->
<TextBlock Grid.Row="2" Grid.Column="1"><Bold>Age:</Bold> <Run Text="{Binding Age, Mode=OneWay}" /></TextBlock>
<TextBlock Grid.Row="2" Grid.Column="2"><Bold>Kids:</Bold> <Run Text="{Binding Kids, Mode=OneWay}" /></TextBlock>
</Grid>
</Border>
</Grid>
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding}" Value="{x:Null}">
<Setter TargetName="ContentGrid" Property="Visibility" Value="Hidden" />
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
<Style TargetType="{x:Type ListBoxItem}" BasedOn="{StaticResource {x:Type ListBoxItem}}">
<!-- I think this should be the default, but it isn't. -->
<Setter Property="HorizontalContentAlignment" Value="Stretch" />
</Style>
</Window.Resources>
<Window.DataContext>
<local:MainViewModel/>
</Window.DataContext>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="8" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="0.5*" />
<RowDefinition Height="0.5*" />
</Grid.RowDefinitions>
<ListBox
x:Name="VNodeMasterList"
Grid.Column="0"
Grid.Row="0"
Grid.RowSpan="2"
Background="{StaticResource ListBackgroundBrush}"
ItemsSource="{Binding VNodes}"
SelectionMode="Extended"
SelectedItem="{Binding SelectedVNode}"
>
<ListBox.Resources>
<Style TargetType="{x:Type ListBoxItem}" BasedOn="{StaticResource {x:Type ListBoxItem}}">
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
</Style>
</ListBox.Resources>
<ListBox.ItemTemplate>
<DataTemplate>
<WrapPanel>
<TextBlock Text="Name: " />
<TextBlock Text="{Binding Name}" FontWeight="Bold" />
</WrapPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<GridSplitter Grid.Column="1" Grid.RowSpan="2" Grid.Row="0" Width="5" HorizontalAlignment="Stretch" />
<Border
Grid.Column="2"
Grid.Row="0"
Background="{StaticResource ListBackgroundBrush}"
>
<ContentControl
Content="{Binding ElementName=VNodeMasterList, Path=SelectedItem}"
ContentTemplate="{StaticResource VNodeCardTemplate}"
/>
</Border>
<ListBox
Grid.Column="2"
Grid.Row="1"
Background="{StaticResource ListBackgroundBrush}"
ItemsSource="{Binding SelectedVNodes}"
ItemTemplate="{StaticResource VNodeCardTemplate}"
/>
</Grid>
</Window>

Upadate TreeView From Class .cs

Good morning for all;
I have a TreeView in my Window WPF, I use DataBinding to cover my TreeView.
Now I have another Class MyDesign.cs , and I want to upade the itms of my TreeView from this Class.
here My code:
MainWindow.xaml:
<Window x:Class="TreeViewAndDataBanding.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:self="clr-namespace:TreeViewAndDataBanding"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<ContextMenu x:Key="MyDesignContextMenu">
<MenuItem Header="Paste" Command="{x:Static ApplicationCommands.Paste}"/>
<MenuItem Header="Search" Command="{x:Static self:MyDesign.Search}"/>
</ContextMenu>
<self:test x:Key="test"/>
</Window.Resources>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="24*"/>
<ColumnDefinition Width="23*"/>
</Grid.ColumnDefinitions>
<TreeView x:Name="MyToolBox" ItemsSource="{StaticResource test}" Grid.Column="1" >
<TreeView.ItemTemplate>
<DataTemplate>
<TreeViewItem Header="All Cars">
<TreeViewItem Header="{Binding Path= Voiture}">
<TreeViewItem Header="{Binding Path=Vitesse}"></TreeViewItem>
</TreeViewItem>
</TreeViewItem>
</DataTemplate>
</TreeView.ItemTemplate>
</TreeView>
<s:MyDesign Focusable="true" x:Name="MyDesigner"
Background="{StaticResource WindowBackgroundBrush}"
Margin="10" FocusVisualStyle="{x:Null}"
ContextMenu="{StaticResource MyDesignContextMenu}" Grid.Coulum="0"/>
</Grid>
</Window>
MenuItem.cs
namespace TreeViewAndDataBanding
{
public class MenuItem
{
private string _Voiture;
private string _Vitesse;
public MenuItem( string Voiture,string Vitesse)
{
this._Voiture = Voiture;
this._Vitesse = Vitesse;
}
public string Voiture
{
get { return _Voiture; }
}
public string Vitesse
{
get { return _Vitesse; }
}
}
}
test.cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
namespace TreeViewAndDataBanding
{
public class test : ObservableCollection<MenuItem>
{
public test()
{
Add(new MenuItem("Rapide", "Ferrari F430"));
}
}
}
And here My class MyDesign.Command.Cs, I want to be able to update my treeView in this Class (in method Search)
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;
namespace TreeViewAndDataBanding
{
public class MyDesign
{
public static RoutedCommand Search = new RoutedCommand();
public MyDesign()
{
this.CommandBindings.Add(new CommandBinding(ApplicationCommands.Paste, Paste_Executed));
this.CommandBindings.Add(new CommandBinding(ApplicationCommands.Paste, Search_Executed));
}
private void Search_Executed(object sender, ExecutedRoutedEventArgs e)
{
// d'ici je veux modifier mon TreeView
/******************************************************************************************/
/****** ici je veux modifier et mettre a jour mon Treeview dans l'interface *************/
/****************************************************************************************/
}
private void Paste_Executed(object sender, ExecutedRoutedEventArgs e)
{
}
}
}
Can You help me please,?? any ideas??
Doing this MVVM style is much cleaner, easier to maintain, and makes WPF make a lot more sense. An example (I've renamed a few things as my French is well. non-existent)
Create a ViewModel:
public class ViewModel {
public ObservableCollection<CarType> CarTypes { get; private set; }
public ViewModel() {
CarsTypes = new ObservableCollection<CarType>();
var sportsCars = new CarType("Sports cars");
sportscars.Cars.Add(new Car() { Make = "Ferrari", Model = "F430" });
CarTypes.Add(sportsCars);
}
}
And your View:
<Window ...
<Window.DataContext>
<local:ViewModel/>
</Window.DataContext>
<Window.Resources>
<HierarchicalDataTemplate ItemsSource="{Binding Cars}" DataType="{x:Type local:CarType}">
<TextBlock Text="{Binding Name}"/>
</HierarchicalDataTemplate>
<DataTemplate DataType="{x:Type local:Car}">
<StackPanel>
<TextBlock Text="{Binding Make}"/>
<TextBlock> - </TextBlock>
<TextBlock Text="{Binding Model}"/>
</DataTemplate>
</Window.Resources>
<TreeView ItemsSource="{Binding CarTypes}"/>
</Window>
Please note that I typed above directly into SO, so I haven't compiled it. I may contains a few errors. But as you can see, using MVVM, this is very little code.
Now you can just add new instances to the Collection on the ViewModel, and your UI will update. Commands can be implemented on the ViewModel using RelayCommands.

How do I create a XAML binding to a member variable?

I'm new to XAML and data binding. I want to define a GUI control in MainWindow.xaml that gets its data from a member variable in MainWindow.xaml.cs. For simplicity's sake I just made a program that displays a counter as well as a button to increment the counter.
Based on earlier threads I've looked up, I came up with the following code:
MainWindow.xaml.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace XAMLBindingTest
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private int Counter
{
get { return (int)GetValue(CounterProperty); }
set { SetValue(CounterProperty, value); }
}
public static readonly DependencyProperty CounterProperty =
DependencyProperty.Register("Counter", typeof(int), typeof(MainWindow), new PropertyMetadata(null));
public MainWindow()
{
Counter = 0;
InitializeComponent();
}
private void incrementCounter(object sender, RoutedEventArgs e)
{
++Counter;
}
}
}
MainWindow.xaml
<Window x:Class="XAMLBindingTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="140" Width="180">
<Grid>
<StackPanel HorizontalAlignment="Left" VerticalAlignment="Top">
<TextBlock x:Name="txbCounter" HorizontalAlignment="Left" TextWrapping="Wrap" Text="{Binding Counter}" VerticalAlignment="Top"/>
<Button x:Name="btnIncrement" Content="Increment" Width="75" Click="incrementCounter"/>
</StackPanel>
</Grid>
</Window>
This example compiles, but the TextBlock isn't showing a counter value. How do I wire the TextBlock to the Counter member in a correct way?
Try adding a "Name" to your window and binding using "ElementName"
<Window x:Class="XAMLBindingTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" Name="UI">
<Grid>
<StackPanel HorizontalAlignment="Left" VerticalAlignment="Top">
<TextBlock x:Name="txbCounter" HorizontalAlignment="Left" TextWrapping="Wrap" Text="{Binding ElementName=UI, Path=Counter}" VerticalAlignment="Top"/>
<Button x:Name="btnIncrement" Content="Increment" Width="75" Click="incrementCounter"/>
</StackPanel>
</Grid>
</Window>
If i understood you correctly:
ItemSource="{Binding Path=TestData, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type common:LayoutAwarePage}}}"
TestData is property of type ObservableCollection declared in .xaml.cs file. ItemSource - is a example property you want bind to.
UPD2:
<ItemsControl ItemSource="{Binding Path=TestData, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type common:LayoutAwarePage}}}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}" />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>

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