I have a ListView:

                <ListView  x:Name="All_Staging_ListView"
                           SelectionMode="Single"
                           SelectionChanged="All_Staging_ListView_SelectionChanged"      
                           ItemTemplate="{StaticResource All_Staging_ListView_Template}"
                           BorderThickness="3"
                           BorderBrush="#005986"
                           HorizontalAlignment="Stretch"/>

I have a DataTemplate for the ListView:

<Page.Resources>
    <DataTemplate x:Key="All_Staging_ListView_Template" x:DataType="local1:All_Staging_Data_Collection_ViewEdit">
        <Border BorderBrush="Aqua" BorderThickness="1" Padding="5" Margin="5">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition/>
                    <RowDefinition/>
                    <RowDefinition/>
                    <RowDefinition/>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="100"/>
                    <ColumnDefinition Width="Auto"/>
                    <ColumnDefinition Width="100"/>
                    <ColumnDefinition Width="*"/>
                    <ColumnDefinition Width="*"/>
                </Grid.ColumnDefinitions>
                <TextBlock Grid.Row="0" Grid.Column="0" Text="{x:Bind Metric_ID}" x:Phase="1" FontWeight="ExtraBold" Margin="0,0,5,0"/>
                <TextBlock Grid.Row="0" Grid.Column="1" Grid.ColumnSpan="2" Text="{x:Bind Period}" Margin="0,0,0,0"/>
                <TextBlock Grid.Row="0" Grid.Column="3" Text="{x:Bind ID}" Margin="25,0,0,0"/>
                <Button Grid.Row="0" Grid.RowSpan="2" Grid.Column="4" x:Name="ButtonListViewEdit" Content="Edit this metric" Margin="20,0,0,0" Visibility="Collapsed" Click="ButtonListViewEdit_Click"/>
                <TextBlock Grid.Row="1" Grid.Column="0" Text="Name:" FontWeight="Bold" />
                <TextBlock Grid.Row="1" Grid.Column="1" Text="{x:Bind Metric_Name}" x:Phase="1" Margin="0,0,20,0"/>
                <TextBlock Grid.Row="1" Grid.Column="2" Text="Product:" FontWeight="Bold"/>
                <TextBlock Grid.Row="1" Grid.Column="3" Text="{x:Bind Product}"/>
                <TextBlock Grid.Row="2" Grid.Column="0" Text="Definition:" FontWeight="Bold"/>
                <TextBlock Grid.Row="2" Grid.Column="1" Text="{x:Bind Metric_Definition}" x:Phase="1" Margin="0,0,20,0"/>
                <TextBlock Grid.Row="2" Grid.Column="2" Text="Company:" FontWeight="Bold" />
                <TextBlock Grid.Row="2" Grid.Column="3" Text="{x:Bind Company}"/>
                <TextBlock Grid.Row="3" Grid.Column="0" Text="Goal:" FontWeight="Bold"/>
                <TextBlock Grid.Row="3" Grid.Column="1" Text="{x:Bind Goal_Description}" x:Phase="1" Margin="0,0,20,0"/>
                <TextBlock Grid.Row="3" Grid.Column="2" Text="System:" FontWeight="Bold"/>
                <TextBlock Grid.Row="3" Grid.Column="3" Text="{x:Bind System}"/>
            </Grid>
        </Border>
    </DataTemplate>
</Page.Resources>

When an item in the ListView is 'selected' I would like to make the button 'ButtonListViewEdit' visible!!!!! Edit: (I would like to make the button in the selected item visible only, not in the other unselected items in the ListView).

I don't know the syntax to reference the button within the datatemplate in the 'SelectionChanged' event handler:

    private void All_Staging_ListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        All_Staging_Data_Collection_ViewEdit listitem = new All_Staging_Data_Collection_ViewEdit();
        listitem = (All_Staging_Data_Collection_ViewEdit)All_Staging_ListView.SelectedItem;
        Debug.WriteLine($"ListView > SelectionChanged > Metric ID: {listitem.Metric_ID}");
    }

I am able to access the values of the bound textblocks, but not the button (to make it visible).

Thank you members of stackoverflow for you help in advance.

CodePudding user response：

Bind the Visibility property of the Button to a property of your All_Staging_Data_Collection_ViewEdit class or get a reference to the Button using the VisualTreeHelper class in your event handler:

private void All_Staging_ListView_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    foreach (object selectedItem in e.AddedItems)
        DisplayOrHideButton(selectedItem, true);
    foreach (object selectedItem in e.RemovedItems)
        DisplayOrHideButton(selectedItem, false);
}

private void DisplayOrHideButton(object item, bool display)
{
    ListViewItem container = All_Staging_ListView.ContainerFromItem(item) as ListViewItem;
    if (container != null)
    {
        Button button = FindVisualChild<Button>(container);
        if (button != null)
            button.Visibility = display ? Visibility.Visible : Visibility.Collapsed;
    }
}

private static T FindVisualChild<T>(DependencyObject obj) where T : DependencyObject
{
    for (int i = 0; i < VisualTreeHelper.GetChildrenCount(obj); i  )
    {
        DependencyObject child = VisualTreeHelper.GetChild(obj, i);
        if (child != null && child is T t)
            return t;
        else
        {
            T childOfChild = FindVisualChild<T>(child);
            if (childOfChild != null)
                return childOfChild;
        }
    }
    return null;
}