We Keep Coding

Is there a way to pass treeViewItem name as command parameter?

I am creating a simple treeview with binding to a collection. What I want is to display full info about the collection element in a listview when treeview element is selected. Similar to windows file explorer. The problem is I cannot bind selected treeviewitem to a Command.
Tried binding command to SelectedItemChanged event with a parameter of treeviewitem name - didn`t work.
Tried it with a simple event - gets cumbersome and breaks MVVM pattern. There must be an elegant way to solve this since what I am trying to do is really widespread in different apps.
<TreeView Grid.Row="1" Background="AliceBlue" ItemsSource="{Binding TopPanelNodes}" Name="TopTreeView" SourceUpdated="TopTreeView_SourceUpdated" >
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Path=Nodes}">
<StackPanel HorizontalAlignment="Left" Orientation="Horizontal" IsEnabled="False">
<TextBlock Text="{Binding Name}" >
</TextBlock>
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectedItemChanged">
<i:InvokeCommandAction Command="{Binding UpdateInspectorCommand }" CommandParameter=??? />
</i:EventTrigger>
</i:Interaction.Triggers>
</TreeView>
I would like to pass treeviewitem name as command parameter instead of ??? in my code so selected treeview item will be identified by name so I can get respective info and bind it to listview.

Solved it using RelativeSource.
CommandParameter="{Binding Path=SelectedItem, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type TreeView}}}"
Works fine.

C# MVVM: MenuItem Command don´t execute in ViewModel

I created a Delete MenuItem and binding a command to it.
Now I have the problem, if I am pressing the Delete MenuItem, nothing happens. Also if the program is executed with the debugger, it never reaches the private void DeleteItem.
xaml:
<ListBox.ItemTemplate>
<DataTemplate>
<Border Background="#F5F5F5" Width="80" Height="60" Margin="0,5,5,5">
<Border.ContextMenu>
<ContextMenu>
<MenuItem Header="Delete"
Command="{Binding Path=DeleteItemCommand, RelativeSource={RelativeSource FindAncestor, AncestorType= MenuItem}}">
<MenuItem.Icon>
<Label FontFamily="#FontAwesome" Content="" />
</MenuItem.Icon>
</MenuItem>
</ContextMenu>
</Border.ContextMenu>
ViewModel:
public ICommand DeleteItemCommand { get; set; }
DeleteItemCommand = new RelayCommand(DeleteItem);
private void DeleteItem(object obj)
{
try
{
// Do Magic
}
catch (Exception)
{
MessageBox.Show(error);
}
}
Would be great, if someone could help me or have any ideas how to solve it, because i can´t find the error.

ContextMenu is indeed not part of the visual tree. But I think because of that reason RelativeSource will not work because the binding will look up to the visual tree for the datacontext. contextMenu is not part of that visual tree so it will not find the proper datacontext. I've found a solution for this in the past using a proxy element in the resources for the window. Then set this proxyelement as content for a hidden contentcontrol in the window. On the menuItem set the CommandBinding to Datacontext.DeleteCommand and the soure to the static resource proxyelement. It is a bit hackish, but it works.
So to show some xaml, try this:
First in the resources of the window create a frameworkelement with the datacontext set to the windows datacontext (the viewmodel)
<Window.Resources>
<FrameworkElement x:Key="ProxyElement" DataContext="{Binding}"/>
</Window.Resources>
Then use the resource for the content of a collapsed content control. And set the proper binding to the menuItem. Something like this:
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<ContentControl Visibility="Collapsed" Content="{StaticResource ProxyElement}"/>
<ListBox x:Name="lbTest" Grid.Row="1">
<ListBox.ItemTemplate>
<DataTemplate>
<Border Background="#F5F5F5" Width="80" Height="60" Margin="0,5,5,5">
<Border.ContextMenu>
<ContextMenu>
<MenuItem Header="Delete"
Command="{Binding DataContext.DeleteCommand, Source={StaticResource ProxyElement}}">
<MenuItem.Icon>
<Label FontFamily="#FontAwesome" Content="" />
</MenuItem.Icon>
</MenuItem>
</ContextMenu>
</Border.ContextMenu>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
This should work. Give it a try.

Not sure if this will help but try using Binding instead of Binding Path.

ContextMenu is not part of VisualTree, that's why the binding fails. You can use some kind of relay like ContextMenu.PlacementTarget.Tag.Property as a cache for the second trail of binding search.
<ContextMenu>
<MenuItem Command="my:ImgTreeView.Folders" Header="Folders"
IsEnabled="{Binding Path=PlacementTarget.Tag.IsCheckFolder, RelativeSource={RelativeSource AncestorType=ContextMenu}}">
<MenuItem.Icon>
<Image Source="StarFolders.png" />
</MenuItem.Icon>
</MenuItem>
<!-- ... -->
</ContextMenu>

WPF Caliburn.Micro ItemsControl ContextMenu don't find method

I'am really having some problems with the ContextMenu from Caliburn.Micro. No matter what I do, I get the error "Cant' find the method ...".
I've tried this solutions, and that one too, but I can't get this to work.
What I'am doing wrong? Actually, there's a way to debug the view and find out in which Context the control is searching for the respective ViewModel?
And another thing... this View is inside a DataTemplate from another view, does that change anything? All the others bindings are working from the correct ViewModel...
<ScrollViewer VerticalScrollBarVisibility="Auto"
HorizontalScrollBarVisibility="Disabled"
Grid.Row="1" Grid.Column="0"
Padding="10,5,15,5"
MaxHeight="390" x:Name="xImages">
<ItemsControl
ItemsSource="{Binding Path=Document.Images}"
dd:DragDrop.IsDragSource="True"
dd:DragDrop.IsDropTarget="True">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Height="110">
<Border Margin="5" BorderBrush="Gainsboro" BorderThickness="1">
<Image Source="{Binding Path=PathThumb}" Width="70" Height="100"> <!-- Tag="{Binding DataContext, ElementName=xImagens}" -->
<Image.ContextMenu>
<ContextMenu
cal:Action.TargetWithoutContext="{Binding DataContext, ElementName=xImagens}"> <!--PlacementTarget.Tag, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"-->
<MenuItem Header="Ampliar"
cal:Message.Attach="[Event Click] = [Action ExpandImage($datacontext)]"></MenuItem>
<MenuItem Header="Excluir"
cal:Message.Attach="[Event Click] = [Action DeleteImage($datacontext)]"></MenuItem>
</ContextMenu>
</Image.ContextMenu>
</Image>
</Border>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Horizontal" ScrollViewer.HorizontalScrollBarVisibility="Disabled" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</ScrollViewer>

cal:Action.TargetWithoutContext="{Binding Source={x:Reference xImagens} , Path=DataContext}">
Because ContextMenu is not part of the VisualTree , you can't bind to elements in the visual tree
of it's TargetPlacement. ( Though in XAML it seems like it is part of it ).
You have two choices:
{Binding Path=PlacementTarget.DataContext}
Or:
{Binding Source={x:Reference xImagens}, Path=DataContext}

give the x:Name="xImages" to the ItemsControl and then do the binding with ElementName to the ContextMenu using the Action.TargetWithoutContext, you had it right but the ScrollViewer isn't what has the Datacontext to the List of data, the ItemControl does since it has the ItemSource.
Was there a reason for naming the ScrollViewer?
<ItemsControl x:Name="xImages">
<ContextMenu Action.TargetWithoutContext="{Binding Path=DataContext, ElementName=xImages}">
<!-- Shortened -->
</ContextMenu>
</ItemsControl>

How to Interact with 2 or More ViewModels

I have written a tool in which a ListBox is bound to a ObserservableCollection<object> with varying datatypes I've define. I use a PropertyDataTemplateSelector to present the data in the ListBox. The PropertyDataTemplateSelector references several DataTemplates that are set as UserControls. There is a background class that provides logic to the PropertyDataTemplateSelector by checking the object type and then applying the correct DataTemplate.
Here's an abbreviated example of the XAML for the UserControls and the MainWindow.
UserControl1
<TextBlock Text="{Binding Path=Val1}"
Style="{StaticResourse Yes}" />
<Button Content="I'm Button 1"
Command="{Binding Path=PathtoCommand1}"
CommandParameter="{Binding Parameter1}"
IsEnabled="{Binding IsEnabled1}" />
<Button Content="I'm Button 2"
Command="{Binding Path=PathtoCommand2}"
CommandParameter="{Binding Parameter2}"
IsEnabled="{Binding IsEnabled2}"
Tag="{Binding Path="DataContext.TagItem2}">
<Button.ContextMenu>
<ContextMenu>
<MenuItem IsCheckable="True"
IsChecked="{Binding Path=Tag}"
DataContext="{Binding Path=PlacementTarget, RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}}" />
</ContextMenu>
</Button.ContextMenu>
</Button>
</StackPanel>
</UserControl>
UserControlN
<UserControl x:Class="AwesomerControl">
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding Path=FancyName2}"
Style="{StaticResourse Yes}" />
<Button Content="Clicker 1"
Command="{Binding Path=DoSomethingGreat1}"
CommandParameter="{Binding Greatness1}"
IsEnabled="{Binding IsTurnedOn1}" />
<Button Content="Clicker 2"
Command="{Binding Path=DoSomethingGreat2}"
CommandParameter="{Binding Greaterness2}"
IsEnabled="{Binding IsTurnedOn2}"
Tag="{Binding Path="DataContext.TagItem2}">
<Button.ContextMenu>
<ContextMenu>
<MenuItem IsCheckable="True"
IsChecked="{Binding Path=Tag}"
DataContext="{Binding Path=PlacementTarget, RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}}" />
</ContextMenu>
</Button.ContextMenu>
</Button>
</StackPanel>
</UserControl>
Here I set the UserControls to a specified DataTemplate. The UserControls were moved out to make the XAML easier to read/navigate. In actuality the UserControls are a few hundred lines each.
<Window.Resources>
<DataTemplate x:Key"Template1">
<customControls:AwesomeControl/>
</DataTemplate>
...
<DataTemplate x:Key"TemplateN">
<customControls:AwesomerControl/>
</DataTemplate>
<dts:PropertyDataTemplateSelector x:Key="templateselector"
Template1="{StaticResource Template1"}
...
TemplateN="{StaticResource TemplateN"}
</Window.Resources>
The ListBox is defined as this.
<ListBox ItemSource="{Binding Path=CollectionofMyObjects}"
ItemTemplateSelector="{StaticResource templateselector}" />
I am using a single ViewModel to drive the MainWindow and the UserControls.
So that's where I'm at, essentially. I have this currently working as I'd like, but in an ongoing effort to learn (this is my first MVVM/WPF/C# project) I'd like to keep exploring how to make my code "better" (however that's defined). I'm not looking to solve an error here. So to avoid a general/broad question, I'll ask what I think I want to know. Someone can correct me and I'll update the "question(s)" appropriately
Question: How can I go about producing a ViewModel for each of the UserControls? Some of the ViewModels, for the UserControls, will occasionally require two-way communication to the MainWindow_ViewModel. The main crux of my problem is figuring out how the multiple VMs will communicate.

You're close, but it's not quite MVVM yet. ;)
First, break out all the functionality that is relevant to each UserControl into their own classes. These are your view-model classes.
Your controls should now become "view" classes, and they deserve their own mark-up file. Rather than use a template selector, you can use the DataTemplate.DataType to automatically connect the view-model class type to its view.
There are a lot of options for communication between view-models. To further your education, I'd consider looking at a light-weight MVVM framework that has built-in solutions for communication. My personal favorite is Caliburn.Micro, which includes an EventAggregator, a service that provides the ability to publish an object from one view-model to another in a loosely-coupled fashion.
Keep learning, you're on the right track!

how to bind a command from DataContext of Page to a list item

I have a Page and a viewmodel is set as its datacontext. in that page I have a list. which is populating through a property in the viewmodel. List has a user control. and that user control has a button. I want that button to be bind with a command that is in viewmodel. Is there anyway to do that?
<Page DataContext=PageViewModel>
...
<ScrollViewer Grid.Row="3" Margin="20,0" Visibility="{Binding ByVenueSelected, Converter={StaticResource BooleanToVisibilityConverter}}">
<StackPanel>
<ItemsControl ItemsSource="{Binding EventsListByVenue}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<myControls:EventDetails /> <!--in this control i want to bind a command available in PageViewModel-->
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
</ScrollViewer>
...
</Page>

with help of #FunksMaName, I solved this. I am sure there are more elegant and better approach, but yet this is a quick & easy solution for me:
<Button Style="{StaticResource NoHighlightButtonStyle}" Tag="{Binding link}" CommandParameter="{Binding Path=Tag,RelativeSource={RelativeSource Mode=Self}}" Visibility="{Binding link,Converter={StaticResource DataAvailabilityToVisibilityConverter}}" Command="{Binding Path=Event.LinkCommand,Source={StaticResource Locator}}" >
<TextBlock Margin="0,5" Foreground="SkyBlue" Text="{Binding link}" TextWrapping="Wrap" FontSize="16"/>
</Button>
things to note:
i think xaml searched the command parameter in context of command only, so it was giving me null parameter, while the same binding was working fine for textblock inside Button. So i tricked it to store the value in tag, and used it from there.
Tag="{Binding link}" CommandParameter="{Binding Path=Tag,RelativeSource={RelativeSource Mode=Self}}"