Add doubleclick-command to wpf-treeview-items - wpf

Question

as I found a lot of tasks (questions) to my question, I still have no idea how that works.
Even it's a much too complex example or simply the needed namespace was missing. So after one hour of research, my question...
How do I intergrate doubleclick-command to my WPF treeview (-items)?
Actually, my tree looks like this:
<!-- used Namespace: xmlns:i="http://schemas.microsoft.com/xaml/behaviors" -->
<TreeView DataContext="{Binding ProjectTree}" ItemsSource="{Binding ProjectNode}" DockPanel.Dock="Left"
x:Name="ProjectTree" Margin="0 0 2 0" Grid.Column="0">
<TreeView.ContextMenu>
<ContextMenu StaysOpen="True">
<MenuItem Header="Löschen" Height="20"
Command="{Binding RemoveNodeCommand}"
CommandParameter="{Binding ElementName=ProjectTree, Path=SelectedItem}">
<MenuItem.Icon>
<Image Source="/Icons/32x32/Remove_32x32.png" Width="15" Height="15"/>
</MenuItem.Icon>
</MenuItem>
</ContextMenu>
</TreeView.ContextMenu>
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectedItemChanged">
<i:InvokeCommandAction Command="{Binding TreeNodeSelectedCommand}"
CommandParameter="{Binding ElementName=ProjectTree, Path=SelectedItem}"/>
</i:EventTrigger>
<i:EventTrigger EventName="MouseDoubleClick">
<i:InvokeCommandAction Command="{Binding UpdateNodeCommand}"
CommandParameter="{Binding ElementName=ProjectTree, Path=SelectedItem}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}"/>
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}"/>
<Setter Property="FontWeight" Value="Normal"/>
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="FontWeight" Value="Bold"/>
</Trigger>
</Style.Triggers>
</Style>
</TreeView.ItemContainerStyle>
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children}">
<StackPanel Orientation="Horizontal">
<Image Margin="3" Source="{Binding ItemType, Converter={x:Static misc:TreeItemImageConverter.Instance }}" Width="20" />
<TextBlock VerticalAlignment="Center" Text="{Binding Name}"/>
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
I don't really understand how the Interaction.Triggers work but should they be the right way?
I'm using the ICommand and a relaycommand for my menu- and button-commands. So far, everything fine in my viewmodels.
Sorry if that is a noob question.
EDIT
As it wasn't a noob question but a noob typo, MouseDoubleClick simply works as SelectedItemChanged so my question was unneccessary. (updated code above)

Answer 1

You can add an interaction trigger in the data template.
I don't have your code so I've adapted a project I already had hanging about to show this working.
My markup, which is of course illustrative rather than cut and paste ready for your purposes:
<TreeView Name="tv" ItemsSource="{Binding Families}" Grid.Row="1" Grid.ColumnSpan="2"
>
<TreeView.Resources>
<HierarchicalDataTemplate DataType="{x:Type local:Family}" ItemsSource="{Binding Members}">
<Border>
<StackPanel Orientation="Horizontal"
Height="32"
>
<Label VerticalAlignment="Center" FontFamily="WingDings" Content="1"/>
<TextBlock Text="{Binding Name}" />
</StackPanel>
</Border>
</HierarchicalDataTemplate>
<DataTemplate DataType="{x:Type local:FamilyMember}">
<ContentControl>
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseDoubleClick">
<i:InvokeCommandAction Command="{Binding DataContext.TestCommand, RelativeSource={RelativeSource AncestorType=TreeView}}"
CommandParameter="{Binding Path=DataContext, RelativeSource={RelativeSource AncestorType=TreeViewItem}}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
<StackPanel Orientation="Horizontal"
Height="32"
x:Name="sp">
<TextBlock Tag="{Binding DataContext.Name,
RelativeSource={RelativeSource AncestorType=TreeViewItem , AncestorLevel=2}
}"
Text="{Binding Name}" />
<TextBlock Text="{Binding Age}" Foreground="Green" />
</StackPanel>
</ContentControl>
</DataTemplate>
</TreeView.Resources>
</TreeView>
The command in my window viewmodel
public class MainWindowViewModel
{
private DelegateCommand<FamilyMember> testCommand;
public ICommand TestCommand
{
get
{
if (testCommand == null)
{
testCommand = new DelegateCommand<FamilyMember>((member) =>
{
MessageBox.Show($"Member's name is {member.Name}");
});
}
return testCommand;
}
}
My tree has family and then each has family members.
If I expand members out I can double click a family member and the message box confirms the name is correct.
Note the contentcontrol in the datatemplate.
You need a control to give you double click support.

Answer 2

Interaction triggers cannot be applied in style setters but you could create an attached behaviour that handles the MouseDoubleClick event for the TreeViewItem:
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="local:YourBehavior.Command" Value="{Binding YourCommand}" />
...
</Style>
Another option is to invoke the command programmtically from the code-behind of the view.