Geek Answers Handbook

The WPF list with the canececute context menu is not called until any

I have a ListBox ItemTemplate related to the ObservableCollection of my items. I'm currently trying to implement Cut / Copy / Paste / SelectAll (so that it is short, I will just show selectall here ...)

<UserControl.CommandBindings>
    <CommandBinding Command="SelectAll" CanExecute="SelectAll_CanExecute" Executed="SelectAll_Executed"/>
</UserControl.CommandBindings>
<ListBox x:Name="listbox" 
         ItemsSource="{Binding}" 
         Background="Transparent" 
         SelectionMode="Extended"
         ScrollViewer.VerticalScrollBarVisibility="Auto">
    <ListBox.ContextMenu>
        <ContextMenu>
            <MenuItem Command="SelectAll" />
        </ContextMenu>
    </ListBox.ContextMenu>
    <ListBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal" Background="Transparent">
                <CheckBox Name="cbEnabled" IsChecked="{Binding Enabled, Mode=TwoWay}" Margin="0,2,0,0"/>
                <TextBlock Text="{Binding Name}" Padding="5,0,0,0"/>
            </StackPanel>
        </DataTemplate>
    </ListBox.ItemTemplate>

this is codebehind for canececute:

    private void SelectAll_CanExecute(object sender, CanExecuteRoutedEventArgs e)
    {
        e.CanExecute = listbox.Items.Count > 0;
        e.Handled = true;
    }

When I first run the program and right-click in the list, the Select All context menu is always turned off (and SelectAll_CanExecute is never called) until I select something. Is there a way to make this work as it seems? (and without automatically selecting the first item or forcing the user to do this)

Thank!

+4
2

, . , CanExecute ContextMenu, CommandBinding , MenuItem CommandTarget , :

<ListBox.ContextMenu>
    <ContextMenu>
        <MenuItem Command="SelectAll"
                    CommandTarget="{Binding Path=PlacementTarget,RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}}">
        </MenuItem>
    </ContextMenu>
</ListBox.ContextMenu>

:

<UserControl x:Class="ListBoxStyle.ListBoxUserControl"
             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="300" d:DesignWidth="300">
    <UserControl.CommandBindings>
        <CommandBinding Command="SelectAll" CanExecute="SelectAll_CanExecute" Executed="SelectAll_Executed"/>
    </UserControl.CommandBindings>
    <Grid>
        <ListBox x:Name="listbox" 
             Background="Transparent" 
             SelectionMode="Extended"
             ScrollViewer.VerticalScrollBarVisibility="Auto">
            <ListBox.ContextMenu>
                <ContextMenu>
                    <MenuItem Command="SelectAll"
                    CommandTarget="{Binding Path=PlacementTarget,RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}}">
                    </MenuItem>
                </ContextMenu>
            </ListBox.ContextMenu>
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <StackPanel Orientation="Horizontal" Background="Transparent">
                        <CheckBox Name="cbEnabled" IsChecked="{Binding Enabled, Mode=TwoWay}" Margin="0,2,0,0"/>
                        <TextBlock Text="{Binding}" Padding="5,0,0,0"/>
                    </StackPanel>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</UserControl>
+6

... UserControl. MenuItems, , MenuItem. :

 <UserControl.Resources>
        <Style TargetType="MenuItem">
            <Setter Property="CommandTarget" Value="{Binding Path=PlacementTarget,RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}}"></Setter>    
        </Style>

...

, - ... Vinkal, . - !!!

0

More articles:


All Articles