Forums | NoesisGUI

<UserControl x:Class="Modules.FileManager.FileManagerView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
             xmlns:noesis="clr-namespace:NoesisGUIExtensions;assembly=Noesis.GUI.Extensions"
             xmlns:local="clr-namespace:Modules.FileManager">
    <UserControl.Resources>

        <Style x:Key="FileManagerListViewStyle" TargetType="{x:Type ListView}">
            <Setter Property="BorderBrush" Value="Black"></Setter>
            <Setter Property="BorderThickness" Value="2"></Setter>
            <Setter Property="Grid.IsSharedSizeScope" Value="True"></Setter>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type ListView}">
                        <ScrollViewer ScrollChanged="OnScrollChanged" Margin="1" Style="{StaticResource StandardScrollViewer}" CanContentScroll="True" VerticalScrollBarVisibility="Visible" HorizontalScrollBarVisibility="Disabled" PanningMode="VerticalOnly" Focusable="false">
                            <local:VirtualizingTilePanel x:Name="tilePanel" IsItemsHost="True" ItemsPerRow="5" ItemsPerCol="3"></local:VirtualizingTilePanel>
                        </ScrollViewer>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </UserControl.Resources>
    <Grid Background="{StaticResource ControlBackgroundBrush}">
        <ListView 
            x:Name="CurrentDirectoryListView"
            KeyDown="OnListViewKeyDown"
            SelectionMode="Single"
            Initialized="ListView_OnInitialized"
            Loaded="ListView_OnLoaded"
            Style="{StaticResource FileManagerListViewStyle}"
            ItemContainerStyle="{StaticResource FileManagerListViewItemStyle}"                    
            ItemsSource="{Binding CurrentDirectoryContents}">
            <ListView.ItemTemplate>
                 <!-- lots of xaml -->
            <ListView.ItemTemplate>
        </ListView>
    </Grid>
</UserControl>

            listView = (ListView)FindName("CurrentDirectoryListView") ?? throw new MemberAccessException("CurrentDirectoryListView");
            virtualizingTilePanel = (VirtualizingTilePanel)listView.Template.FindName("tilePanel") ?? throw new MemberAccessException("tilePanel");

    public class VirtualizingTilePanel : VirtualizingPanel, IScrollInfo
    {
    	...
    	ItemsControl itemsControl = ItemsControl.GetItemsOwner(this); // This returns null 

listView = (ListView)FindName("CurrentDirectoryListView") ?? throw new MemberAccessException("CurrentDirectoryListView");
virtualizingTilePanel = (VirtualizingTilePanel)listView.Template.FindName("tilePanel", listView) ?? throw new MemberAccessException("tilePanel");

        private void ListView_OnLoaded(object sender, Noesis.EventArgs args)
        {
            listView = (ListView)FindName("CurrentDirectoryListView") ?? throw new MemberAccessException("CurrentDirectoryListView");
            virtualizingTilePanel = (VirtualizingTilePanel)listView.Template.FindName("tilePanel", listView) ?? throw new MemberAccessException("tilePanel");
            ScrollViewer sv = virtualizingTilePanel.FindAncestors().OfType<ScrollViewer>().FirstOrDefault();
            virtualizingTilePanel.ScrollOwner = sv;
            virtualizingTilePanel.ScrollOwner.ScrollChanged += OnScrollChanged;

            if (viewModel.CurrentDirectoryContents.Count >= 1)
            {
                // Pre-generates item containers
                listView.UpdateLayout();

                var item = (ListViewItem)listView
                    .ItemContainerGenerator
                    .ContainerFromIndex(0);
                listView.SelectedItem = item;
                listView.Focus();
            }
        }

        public void MouseWheelUp()
        {
            MouseWheelUp(10);
        }

        public void MouseWheelUp(float delta)
        {
            SetVerticalOffset(this.VerticalOffset - delta);
        }

        public void MouseWheelDown()
        {
            MouseWheelDown(10);
        }

        public void MouseWheelDown(float delta)
        {
            SetVerticalOffset(this.VerticalOffset + delta);
        }
        

        
        public void SetVerticalOffset(float offset)
        {
            if (offset < 0 || _viewport.Height >= _extent.Height)
            {
                offset = 0;
            }
            else
            {
                if (offset + _viewport.Height >= _extent.Height)
                {
                    offset = _extent.Height - _viewport.Height;
                }
            }

            _offset.Y = offset;

            if (_owner != null)
                _owner.InvalidateScrollInfo();

            _trans.Y = -offset;

            // Force us to realize the correct children
            InvalidateMeasure();
        }