WPF: Scrolling the Content of a Fixed Header Control

Question

Is it possible to do something similar using WPF ItemsControl: Demo

I am trying to freeze GroupedItems, not GridView columns.

Resources

<Window.Resources> <CollectionViewSource x:Key="data" Source="{Binding}"> <CollectionViewSource.GroupDescriptions> <PropertyGroupDescription PropertyName="Date"/> </CollectionViewSource.GroupDescriptions> </CollectionViewSource> </Window.Resources> 

Listview

 <ListView Grid.Column="0" ItemsSource="{Binding Source={StaticResource data}}"> <ListView.View> <GridView> <GridView.Columns> <GridViewColumn Header="Col 1" DisplayMemberBinding="{Binding Col1}" Width="100"/> <GridViewColumn Header="Col 2" DisplayMemberBinding="{Binding Col2}" Width="100"/> <GridViewColumn Header="Col 3" DisplayMemberBinding="{Binding Col3}" Width="100"/> </GridView.Columns> </GridView> </ListView.View> <ListView.GroupStyle> <GroupStyle> <GroupStyle.ContainerStyle> <Style TargetType="{x:Type GroupItem}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type GroupItem}"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> </Grid.RowDefinitions> <Grid Grid.Row="0"> <Grid.ColumnDefinitions> <ColumnDefinition Width="*"/> </Grid.ColumnDefinitions> <TextBlock Background="Beige" FontWeight="Bold" Text="{Binding Path=Name, StringFormat={}{0}}"/> </Grid> <DockPanel Grid.Row="1"> <ItemsPresenter Grid.Row="2"></ItemsPresenter> </DockPanel> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> </GroupStyle.ContainerStyle> </GroupStyle> </ListView.GroupStyle> </ListView> 

CODE BEHIND:

 public MainWindow() { InitializeComponent(); List<String> colList1 = new List<string>(){"Item1", "Item2", "Item3", "Item4", "Item5", "Item6", "Item7"}; List<String> colList2 = new List<string>(){"1", "2", "3", "4", "5", "6"}; ObservableCollection<Data> dataCollection = new ObservableCollection<Data>(); for (var a = 0; a<100; a++){ Random rnd = new Random(); int min = rnd.Next(5000); int rnd1 = rnd.Next(0, 6); int rnd2 = rnd.Next(0, 5); dataCollection .Add( new Data(){ Date = DateTime.Now.AddMinutes(min).ToString("hh:MM tt"), Col1= colList1[rnd2], Col2= String.Format("Col2: {0}", "X"), Col3= colList2[rnd2] } ); } this.DataContext = dataCollection; } public class Data { public string Date { get; set; } public string Col1{ get; set; } public string Col2{ get; set; } public string Col3{ get; set; } } 

Answer 1

My solution uses a TextBlock overlay that shares the group header style. Positioning and correctness of HitTesting is a difficult part, but I am sure that this does not break small changes in layout or logic.

I was not sure if you want to hide the ColumnHeader or not, but it is easy and does not need any other settings than what is shown here .

Code behind:

 using System; using System.Collections.Generic; using System.Collections.ObjectModel; using System.Windows; using System.Windows.Controls; using System.Windows.Media; namespace WpfApplication1 { public partial class FreezingGroupHeader : UserControl { private double _listviewHeaderHeight; private double _listviewSideMargin; public FreezingGroupHeader() { InitializeComponent(); List<String> colList1 = new List<string>() { "Item1", "Item2", "Item3", "Item4", "Item5", "Item6", "Item7" }; List<String> colList2 = new List<string>() { "1", "2", "3", "4", "5", "6" }; ObservableCollection<Data> dataCollection = new ObservableCollection<Data>(); Random rnd = new Random(); for (var a = 0; a < 100; a++) { int min = rnd.Next(5000); int rnd1 = rnd.Next(0, 6); int rnd2 = rnd.Next(0, 5); dataCollection.Add( new Data() { Date = DateTime.Now.AddMinutes(min).ToString("hh:MM tt"), Col1 = colList1[rnd2], Col2 = String.Format("Col2: {0}", "X"), Col3 = colList2[rnd2] } ); } this.DataContext = dataCollection; this.Loaded += OnLoaded; } private void OnLoaded(object sender, RoutedEventArgs e) { // Position frozen header GetListViewMargins(this.listview1); Thickness margin = this.frozenGroupHeader.Margin; margin.Top = _listviewHeaderHeight; margin.Right = SystemParameters.VerticalScrollBarWidth + _listviewSideMargin; margin.Left = _listviewSideMargin; this.frozenGroupHeader.Margin = margin; UpdateFrozenGroupHeader(); } private void listview1_ScrollChanged(object sender, ScrollChangedEventArgs e) { UpdateFrozenGroupHeader(); } /// <summary> /// Sets text and visibility of frozen header /// </summary> private void UpdateFrozenGroupHeader() { if (listview1.HasItems) { // Text of frozenGroupHeader GroupItem group = GetFirstVisibleGroupItem(this.listview1); if (group != null) { object data = group.Content; this.frozenGroupHeader.Text = data.GetType().GetProperty("Name").GetValue(data, null) as string; // slight hack } this.frozenGroupHeader.Visibility = Visibility.Visible; } else this.frozenGroupHeader.Visibility = Visibility.Collapsed; } /// <summary> /// Sets values that will be used in the positioning of the frozen header /// </summary> private void GetListViewMargins(ListView listview) { if (listview.HasItems) { object o = listview.Items[0]; ListViewItem firstItem = (ListViewItem)listview.ItemContainerGenerator.ContainerFromItem(o); if (firstItem != null) { GroupItem group = FindUpVisualTree<GroupItem>(firstItem); Point p = group.TranslatePoint(new Point(0, 0), listview); _listviewHeaderHeight = pY; // height of columnheader _listviewSideMargin = pX; // listview borders } } } /// <summary> /// Gets the first visible GroupItem in the listview /// </summary> private GroupItem GetFirstVisibleGroupItem(ListView listview) { HitTestResult hitTest = VisualTreeHelper.HitTest(listview, new Point(5, _listviewHeaderHeight + 5)); GroupItem group = FindUpVisualTree<GroupItem>(hitTest.VisualHit); return group; } /// <summary> /// walk up the visual tree to find object of type T, starting from initial object /// http://www.codeproject.com/Tips/75816/Walk-up-the-Visual-Tree /// </summary> private static T FindUpVisualTree<T>(DependencyObject initial) where T : DependencyObject { DependencyObject current = initial; while (current != null && current.GetType() != typeof(T)) { current = VisualTreeHelper.GetParent(current); } return current as T; } public class Data { public string Date { get; set; } public string Col1 { get; set; } public string Col2 { get; set; } public string Col3 { get; set; } } } } 

Xaml:

 <UserControl x:Class="WpfApplication1.FreezingGroupHeader" 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.Resources> <CollectionViewSource x:Key="data" Source="{Binding}"> <CollectionViewSource.GroupDescriptions> <PropertyGroupDescription PropertyName="Date"/> </CollectionViewSource.GroupDescriptions> </CollectionViewSource> <Style x:Key="GroupHeaderStyle1" TargetType="{x:Type TextBlock}"> <Setter Property="Background" Value="Beige" /> <Setter Property="Foreground" Value="Black" /> <Setter Property="FontWeight" Value="Bold" /> </Style> </UserControl.Resources> <Grid> <ListView x:Name="listview1" Grid.Column="0" ItemsSource="{Binding Source={StaticResource data}}" ScrollViewer.ScrollChanged="listview1_ScrollChanged" > <ListView.View> <GridView> <GridView.Columns> <GridViewColumn Header="Col 1" DisplayMemberBinding="{Binding Col1}" Width="100"/> <GridViewColumn Header="Col 2" DisplayMemberBinding="{Binding Col2}" Width="100"/> <GridViewColumn Header="Col 3" DisplayMemberBinding="{Binding Col3}" Width="100"/> </GridView.Columns> </GridView> </ListView.View> <ListView.GroupStyle> <GroupStyle> <GroupStyle.ContainerStyle> <Style TargetType="{x:Type GroupItem}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type GroupItem}"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> </Grid.RowDefinitions> <Grid Grid.Row="0"> <Grid.ColumnDefinitions> <ColumnDefinition Width="*"/> </Grid.ColumnDefinitions> <TextBlock Style="{StaticResource GroupHeaderStyle1}" Text="{Binding Name, StringFormat={}{0}}" /> </Grid> <DockPanel Grid.Row="1"> <ItemsPresenter Grid.Row="2"></ItemsPresenter> </DockPanel> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> </GroupStyle.ContainerStyle> </GroupStyle> </ListView.GroupStyle> </ListView> <TextBlock x:Name="frozenGroupHeader" Style="{StaticResource GroupHeaderStyle1}" VerticalAlignment="Top"/> </Grid> </UserControl> 

Answer 2

This solution is not very great, and it is a hack-ish, but it will basically do what you want. I made the listview headers invisible, placed a text block above the list, and set the text value to the groupitem of the first visible item in the list. Hacky, but this is the best I've come up with.

 public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); List<String> colList1 = new List<string>() { "Item1", "Item2", "Item3", "Item4", "Item5", "Item6", "Item7" }; List<String> colList2 = new List<string>() { "1", "2", "3", "4", "5", "6" }; ObservableCollection<Data> dataCollection = new ObservableCollection<Data>(); for (var a = 0; a < 100; a++) { Random rnd = new Random(); int min = rnd.Next(5000); int rnd1 = rnd.Next(0, 6); int rnd2 = rnd.Next(0, 5); dataCollection.Add( new Data() { Date = DateTime.Now.AddMinutes(min).ToString("hh:MM tt"), Col1 = colList1[rnd2], Col2 = String.Format("Col2: {0}", "X"), Col3 = colList2[rnd2] } ); } this.DataContext = dataCollection; } public class Data { public string Date { get; set; } public string Col1 { get; set; } public string Col2 { get; set; } public string Col3 { get; set; } } private void grid_ScrollChanged(object sender, ScrollChangedEventArgs e) { if (grid.Items.Count > 0) { HitTestResult hitTest = VisualTreeHelper.HitTest(grid, new Point(5, 5)); System.Windows.Controls.ListViewItem item = GetListViewItemFromEvent(null, hitTest.VisualHit) as System.Windows.Controls.ListViewItem; if (item != null) Head.Text = ((Data)item.Content).Date; } } System.Windows.Controls.ListViewItem GetListViewItemFromEvent(object sender, object originalSource) { DependencyObject depObj = originalSource as DependencyObject; if (depObj != null) { // go up the visual hierarchy until we find the list view item the click came from // the click might have been on the grid or column headers so we need to cater for this DependencyObject current = depObj; while (current != null && current != grid) { System.Windows.Controls.ListViewItem ListViewItem = current as System.Windows.Controls.ListViewItem; if (ListViewItem != null) { return ListViewItem; } current = VisualTreeHelper.GetParent(current); } } return null; } } 

XAML:

 <Window x:Class="header.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="auto" SizeToContent="Width"> <Window.Resources> <CollectionViewSource x:Key="data" Source="{Binding}"> <CollectionViewSource.GroupDescriptions> <PropertyGroupDescription PropertyName="Date"/> </CollectionViewSource.GroupDescriptions> </CollectionViewSource> <Style x:Key="myHeaderStyle" TargetType="{x:Type GridViewColumnHeader}"> <Setter Property="Visibility" Value="Collapsed" /> </Style> </Window.Resources> <Grid> <StackPanel> <TextBlock Name="Head" Grid.Row="0"/> <ListView Name="grid" Grid.Column="0" Grid.Row="1" ItemsSource="{Binding Source={StaticResource data}}" Height="300" ScrollViewer.ScrollChanged="grid_ScrollChanged"> <ListView.View> <GridView ColumnHeaderContainerStyle="{StaticResource myHeaderStyle}"> <GridView.Columns> <GridViewColumn DisplayMemberBinding="{Binding Col1}" Width="100"/> <GridViewColumn DisplayMemberBinding="{Binding Col2}" Width="100"/> <GridViewColumn DisplayMemberBinding="{Binding Col3}" Width="100"/> </GridView.Columns> </GridView> </ListView.View> <ListView.GroupStyle> <GroupStyle> <GroupStyle.ContainerStyle> <Style TargetType="{x:Type GroupItem}"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type GroupItem}"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> </Grid.RowDefinitions> <Grid Grid.Row="0"> <Grid.ColumnDefinitions> <ColumnDefinition Width="*"/> </Grid.ColumnDefinitions> <TextBlock Background="Beige" FontWeight="Bold" Text="{Binding Path=Name, StringFormat={}{0}}"/> </Grid> <DockPanel Grid.Row="1"> <ItemsPresenter Grid.Row="2"></ItemsPresenter> </DockPanel> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> </GroupStyle.ContainerStyle> </GroupStyle> </ListView.GroupStyle> </ListView> </StackPanel> </Grid> 

EDIT: Fixed ScrollChanged event.

 private void grid_ScrollChanged(object sender, ScrollChangedEventArgs e) { if (grid.Items.Count > 0) { Point point = new Point(5, 5); foreach(Data lvItem in grid.Items) { HitTestResult hitTest = VisualTreeHelper.HitTest(grid, point); ListViewItem item = GetListViewItemFromEvent(null, hitTest.VisualHit) as System.Windows.Controls.ListViewItem; if (item != null) { Data value = ((Data)item.Content); Head.Text = ((Data)item.Content).Date; break; } else { point.X += 5; point.Y += 5; } } } } 

Answer 3

As soon as I encountered a similar problem, and the hack-ish solution did not meet my needs, and I generally do not like hack-ish in production environments, I developed a general solution for this, I would like to share it. A nested class has the following key functions:

• MVVM compatible
• no Code-Behind
• compatible with ListView, GridView, ItemsControl, even static xaml! - should work with anything using ScollViewer ...
• Uses an attached property to declare a group item.

Using xaml (only your internal ControlTemplate):

 <ControlTemplate TargetType="{x:Type GroupItem}"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> </Grid.RowDefinitions> <Grid Grid.Row="0" local:StickyScrollHeader.AttachToControl="{Binding RelativeSource={RelativeSource Mode=FindAncestor,AncestorType=Grid}}"> <TextBlock Background="Beige" FontWeight="Bold" Text="{Binding Path=Name, StringFormat={}{0}}"/> <Grid.ColumnDefinitions> <ColumnDefinition Width="*"/> </Grid.ColumnDefinitions> </Grid> <DockPanel Grid.Row="1"> <ItemsPresenter Grid.Row="2"></ItemsPresenter> </DockPanel> </Grid> </ControlTemplate> 

Class (put anywhere, add xaml namespace if necessary):

 public static class StickyScrollHeader { public static FrameworkElement GetAttachToControl(FrameworkElement obj) { return (FrameworkElement)obj.GetValue(AttachToControlProperty); } public static void SetAttachToControl(FrameworkElement obj, FrameworkElement value) { obj.SetValue(AttachToControlProperty, value); } private static ScrollViewer FindScrollViewer(FrameworkElement item) { FrameworkElement treeItem = item; FrameworkElement directItem = item; while (treeItem != null) { treeItem = VisualTreeHelper.GetParent(treeItem) as FrameworkElement; if (treeItem is ScrollViewer) { return treeItem as ScrollViewer; } else if (treeItem is ScrollContentPresenter) { return (treeItem as ScrollContentPresenter).ScrollOwner; } } while (directItem != null) { directItem = directItem.Parent as FrameworkElement; if (directItem is ScrollViewer) { return directItem as ScrollViewer; } else if (directItem is ScrollContentPresenter) { return (directItem as ScrollContentPresenter).ScrollOwner; } } return null; } private static ScrollContentPresenter FindScrollContentPresenter(FrameworkElement sv) { int childCount = VisualTreeHelper.GetChildrenCount(sv); for (int i = 0; i < childCount; i++) { if (VisualTreeHelper.GetChild(sv, i) is FrameworkElement child && child is ScrollContentPresenter) { return child as ScrollContentPresenter; } } for (int i = 0; i < childCount; i++) { if (FindScrollContentPresenter(VisualTreeHelper.GetChild(sv, i) as FrameworkElement) is FrameworkElement child && child is ScrollContentPresenter) { return child as ScrollContentPresenter; } } return null; } public static readonly DependencyProperty AttachToControlProperty = DependencyProperty.RegisterAttached("AttachToControl", typeof(FrameworkElement), typeof(StickyScrollHeader), new PropertyMetadata(null, (s, e) => { try { if (!(s is FrameworkElement targetControl)) { return; } Canvas.SetZIndex(targetControl, 999); ScrollViewer sv; FrameworkElement parent; if (e.OldValue is FrameworkElement oldParentControl) { ScrollViewer oldSv = FindScrollViewer(oldParentControl); parent = oldParentControl; oldSv.ScrollChanged -= Sv_ScrollChanged; } if (e.NewValue is FrameworkElement newParentControl) { sv = FindScrollViewer(newParentControl); parent = newParentControl; sv.ScrollChanged += Sv_ScrollChanged; } void Sv_ScrollChanged(object sender, ScrollChangedEventArgs sce) { if (!parent.IsVisible) { return; } try { ScrollViewer isv = sender as ScrollViewer; ScrollContentPresenter scp = FindScrollContentPresenter(isv); var relativeTransform = parent.TransformToAncestor(scp); Rect parentRenderRect = relativeTransform.TransformBounds(new Rect(new Point(0, 0), parent.RenderSize)); Rect intersectingRect = Rect.Intersect(new Rect(new Point(0, 0), scp.RenderSize), parentRenderRect); if (intersectingRect != Rect.Empty) { TranslateTransform targetTransform = new TranslateTransform(); if (parentRenderRect.Top < 0) { double tempTop = (parentRenderRect.Top * -1); if (tempTop + targetControl.RenderSize.Height < parent.RenderSize.Height) { targetTransform.Y = tempTop; } else if (tempTop < parent.RenderSize.Height) { targetTransform.Y = tempTop - (targetControl.RenderSize.Height - intersectingRect.Height); } } else { targetTransform.Y = 0; } targetControl.RenderTransform = targetTransform; } } catch { } } } catch { } })); } 

Hope this also helps others in this matter;)