WPF: Scroll Itemcontrol Content Fixed Header
Is it possible to do something like this with WPF's ItemsControl: Demo
I am trying to freeze the GroupedItems rather than the 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; }
}
My solution uses a TextBlock overlay that shares the group header style. The positioning and correct HitTesting is the tricky part, but I'm quite confident this does not break for small changes in layout or logic.
I was not sure if you want to hide the ColumnHeader or not, but this is easy and doesn't need any other adjustments than what is depicted 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 = p.Y; // height of columnheader
_listviewSideMargin = p.X; // 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>
This solution is not great, and it's hack-ish, but it will basically do what you want. I made the listview headers invisible, put a textblock above the listview, and set the text value to the groupitem of the first visible item in the listbox. Hacky, but it's the best I came 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;
}
}
}
}
As i just ran into a similar issue and the 'hack-ish' solution did not fit my needs and i generally dont like 'hack-ish' stuff in production environments, i developed a generic solution to this which i'd like to share. The attached Class has following key-features:
xaml usage (just your inner 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>
The 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 running into this issue ;)
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