CODEWITHSUNDEEP
c#wpfxamltreeviewcaliburn.micro
mardok
mardok

Reputation: 2415

Copy/Paste on TreeView with Caliburn.Micro

I'm trying to implement copy&paste on WPF TreeView with Caliburn.Micro but I stuck at the beginning. Problem is that I don't know to get current item on TreeView was copied or pasted when event is invoked. Below is xaml for TreeView and event handler. Any suggestion?

    <TreeView Name="Nodes" AllowDrop="True">
        <TreeView.ContextMenu>
            <ContextMenu ItemsSource="{Binding MenuItems}">
                <MenuItem Header="Copy" cal:Message.Attach="[Event Click] = [Action Copy($source, $eventArgs)]"></MenuItem>
                <MenuItem Header="Cut" cal:Message.Attach="[Event Click] = [Action Cut]"></MenuItem>
                <MenuItem Header="Paste" cal:Message.Attach="[Event Click] = [Action Paste($this)]" IsEnabled="{Binding IsPasteEnabled}"></MenuItem>
                <ContextMenu.ItemContainerStyle>
                    <Style TargetType="MenuItem">
                        <Setter Property="Header" Value="{Binding Name}"/>
                        <Setter Property="IsEnabled" Value="{Binding IsEnabled}"/>
                        <Setter Property="Command" Value="{Binding MenuCommand}"/>
                    </Style>
                </ContextMenu.ItemContainerStyle>
            </ContextMenu>
        </TreeView.ContextMenu>
        <TreeView.ItemContainerStyle>
            <Style TargetType="{x:Type TreeViewItem}">
                <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" />
                <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
            </Style>
        </TreeView.ItemContainerStyle>
        <TreeView.Resources>
            <HierarchicalDataTemplate ItemsSource="{Binding Childs}" DataType="{x:Type viewmodels:TreeListViewModel+Node}">
                <TextBlock Text="{Binding Name}" />
            </HierarchicalDataTemplate>
        </TreeView.Resources>
    </TreeView>

public void Copy(object sender, RoutedEventArgs args)
{
    // to do...
}

Edited: Source: http://dfiles.eu/files/bsm545ti3

Upvotes: 1

Views: 1071

Answers (1)

Chris
Chris

Reputation: 8656

This might not be useful, but I did something similar using the cal:Action.TargetWithoutContext property to resolve the DataContext to a particular ViewModel. In my case I had several different types of ViewModel all inheriting from a base TreeViewItemViewModel class, but that shouldn't really be something you need to consider here.

Essentially, I was setting the DataContext of the ContextMenu to the actual ViewModel represented by the current TreeView node, allowing me to call an action I had defined on the ViewModel.

In your case, you probably don't want a generic Copy/Paste defined on the ViewModel, but you may be able to fire Copy/Cut/Paste events (using the Caliburn.Micro EventAggregator), from each of the ViewModels, passing themselves in the event information.

The important bit:

<ContextMenu cal:Action.TargetWithoutContext="{Binding DataContext, RelativeSource={RelativeSource Self}}">

I'd defined different a ContextMenu depending on what the node represented, so it lived in the HierarchicalDataTemplate. It looked something like this (I was using a StackPanel to display multiple objects, allowing a ContextMenu to appear if the StackPanel itself was clicked.

<HierarchicalDataTemplate ItemsSource="{Binding Childs}"
                          DataType="{x:Type viewmodels:TreeListViewModel+Node}">
    <StackPanel Orientation="Horizontal">
        <StackPanel.ContextMenu>
            <ContextMenu cal:Action.TargetWithoutContext="{Binding DataContext, RelativeSource={RelativeSource Self}}">
                <MenuItem Header="Cut" cal:Message.Attach="Cut" />
                <MenuItem Header="Copy" cal:Message.Attach="Copy" />
                <MenuItem Header="Paste" cal:Message.Attach="Paste" />
            </ContextMenu>
        </StackPanel.ContextMenu>
        <TextBlock Text="{Binding Name}" />
    </StackPanel>
</HierarchicalDataTemplate>

There may be a much simpler/straightforward approach.

Also worth searching the Caliburn.Micro discussions, e.g: http://caliburnmicro.codeplex.com/discussions/256163

Upvotes: 2

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