I have a scrollviewer with a couple listboxes in it. The problem is if a user uses the middle mouse roller to scroll the scrollviewer while their mouse is over a listview. The listview scrolls its internal scrollviewer to the bottom and then continues to capture the mouse, preventing the containing scrollviewer from scrolling.
Any ideas on how to handle this?
That happens because the ListView's (ListBox's, actually) content template wraps its items with a ScrollViewer by itself.
The simplest way is to disable it by dropping your own Template for the inside ListView, one that doesn't create a ScrollViewer:
<ListView>
<ListView.Template>
<ControlTemplate>
<ItemsPresenter></ItemsPresenter>
</ControlTemplate>
</ListView.Template>
...
</ListView>
BTW the same happens if you have a ListView inside a ListView (this was my case).
IMO, the best way to handle this scenario is to create a custom control :
class MyScrollViewer : ScrollViewer
{
protected override void OnPreviewMouseWheel(MouseWheelEventArgs e)
{
base.OnPreviewMouseWheel(e);
if (!e.Handled)
{
e.Handled = true;
this.RaiseEvent(new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta)
{
RoutedEvent = UIElement.MouseWheelEvent,
Source = this
});
}
}
}
Did you try disabling the ListView's ScrollBars?
<ListView ScrollViewer.HorizontalScrollBarVisibility="Disabled"
ScrollViewer.VerticalScrollBarVisibility="Disabled" />
Inspired by some helpful answers, I have an implementation that scrolls ancestor ScrollViewers when inner ones (including from ListView, ListBox, DataGrid) scroll past their top/bottom.
I apply an attached property to all ScrollViewers in App.xaml:
<Style TargetType="ScrollViewer" BasedOn="{StaticResource {x:Type ScrollViewer}}">
<Setter Property="local:ScrollViewerHelper.FixMouseWheel" Value="True" />
</Style>
The attached property detects scrolling past top/bottom, and when that happens raises a mouse wheel event on the ScrollViewer's parent. Event routing gets it to the outer ScrollViewer:
public static class ScrollViewerHelper
{
// Attached property boilerplate
public static bool GetFixMouseWheel(ScrollViewer scrollViewer) => (bool)scrollViewer?.GetValue(FixMouseWheelProperty);
public static void SetFixMouseWheel(ScrollViewer scrollViewer, bool value) => scrollViewer?.SetValue(FixMouseWheelProperty, value);
public static readonly DependencyProperty FixMouseWheelProperty =
DependencyProperty.RegisterAttached("FixMouseWheel", typeof(bool), typeof(ScrollViewerHelper),
new PropertyMetadata(OnFixMouseWheelChanged));
// End attached property boilerplate
static void OnFixMouseWheelChanged(DependencyObject d,
DependencyPropertyChangedEventArgs e)
{
var scrollViewer = d as ScrollViewer;
if (scrollViewer == null) return;
scrollViewer.PreviewMouseWheel += (s2, e2) =>
{
var parent = scrollViewer.Parent as UIElement;
bool hitTopOrBottom = HitTopOrBottom(e2.Delta, scrollViewer);
if (parent is null || !hitTopOrBottom) return;
var argsCopy = Copy(e2);
parent.RaiseEvent(argsCopy);
};
}
static bool HitTopOrBottom(double delta, ScrollViewer scrollViewer)
{
var contentVerticalOffset = scrollViewer.ContentVerticalOffset;
var atTop = contentVerticalOffset == 0;
var movedUp = delta > 0;
var hitTop = atTop && movedUp;
var atBottom =
contentVerticalOffset == scrollViewer.ScrollableHeight;
var movedDown = delta < 0;
var hitBottom = atBottom && movedDown;
return hitTop || hitBottom;
}
static MouseWheelEventArgs Copy(MouseWheelEventArgs e)
=> new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta)
{
RoutedEvent = UIElement.MouseWheelEvent,
Source = e.Source,
};
}
If you wrap the inner listview in a scrollviewer then the scrolling will work.
<ListView ScrollViewer.VerticalScrollBarVisibility="Auto" ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<ListView.ItemTemplate>
<DataTemplate>
<ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Disabled">
<ListView>
<ListView.ItemTemplate>
<DataTemplate>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ScrollViewer>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
Related
I have an Itemsstackpanel inside a Listview Control. I want to fire the PointerWheelChanged event whenever the User is near the edge of a page.
When i put the event on the itemsstackpanel is disables my ability to scroll by mouse wheel. If the event is on the Listview or Grid itself it only works as long as no Items are done loading in the Listview.
Is this intended behaviour or am i missing some important information?
I researched but found no lead to this problem or behaviour.
below is my XAML:
<Grid Background="Gray">
<ProgressRing x:Name="progress" IsActive="False" x:FieldModifier="public" Foreground="Black" Height="200" Width="200"/>
<ListView x:Name="ListViewControl" x:FieldModifier="public" Margin="10,10,10,10" ScrollViewer.HorizontalScrollBarVisibility="Disabled"
ScrollViewer.ZoomMode="Enabled" ScrollViewer.VerticalScrollBarVisibility="Visible" DataFetchSize="10" IncrementalLoadingTrigger="Edge"
IncrementalLoadingThreshold="2" ShowsScrollingPlaceholders="True" BorderThickness="1" IsItemClickEnabled="False" SelectionMode="None" PointerEntered="ListViewControl_PointerEntered">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="HorizontalContentAlignment" Value="Center"/>
</Style>
</ListView.ItemContainerStyle>
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<ItemsStackPanel CacheLength="0" Orientation="Vertical" Background="White" PointerWheelChanged="Grid_PointerWheelChanged"/>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
</Grid>
and the code behind(not done just trying to get it to work for now):
private void ItemsStackPanel_PointerWheelChanged(object sender, PointerRoutedEventArgs e)
{
e.Handled = true;
PointerPoint pointerPoint = e.GetCurrentPoint(ListViewControl);
float scrolledDistance = pointerPoint.Properties.MouseWheelDelta;
if (scrolledDistance >=120)
{
//Load Page above current Page at a certain mousewheel point
}
else if (scrolledDistance <= -120 )
{
//Load Page below current Page at certain mousewheel point
}
else
{
//do some other stuff
}
}
The default ControlTemplate of ListView contains a ScrollViewer control. PointerWheelChanged is a relatively low-level event that will be intercepted by ScrollViewer.
If you want to monitor the change of the scrolling distance, PointerWheelChanged is not a recommended event. You can listen to the ScrollViewer.ViewChanged event and use ScrollViewer.VerticalOffset to determine the vertical scrolling distance.
We can create a custom ListView to achieve this:
CustomListView.cs
public class CustomListView:ListView
{
private ScrollViewer _scrollViewer;
public event EventHandler<ScrollViewerViewChangedEventArgs> ViewChanged;
public CustomListView()
{
this.DefaultStyleKey = typeof(ListView);
}
protected override void OnApplyTemplate()
{
_scrollViewer = GetTemplateChild("ScrollViewer") as ScrollViewer;
if (_scrollViewer != null)
{
_scrollViewer.ViewChanged += CustomViewChange;
}
base.OnApplyTemplate();
}
private void CustomViewChange(object sender, ScrollViewerViewChangedEventArgs e)
{
ViewChanged?.Invoke(sender, e);
}
}
Usage
<controls:CustomListView x:Name="ListViewControl"
ViewChanged="ListViewControl_ViewChanged"
...>
<!--other content-->
</controls:CustomListView>
private void ListViewControl_ViewChanged(object sender, ScrollViewerViewChangedEventArgs e)
{
var scrollViewer = sender as ScrollViewer;
double scrollHeight = scrollViewer.VerticalOffset;
if (scrollHeight > 120)
{
//Do Something...
}
else
{
//Do something...
}
}
I want to increase the size of a TextBox Control whenever the user drag a node from Treeview control and hovers the mouse over the TextBox.
The size increase should not readjust the other controls, rather the current control should overlap the neighboring controls.
I tried to implement the code WPF: On Mouse hover on a particular control, increase its size and overlap on the other controls
but it doesn't work when hover on TextBox and left mouse button is pressed for dragged text.
<ItemsControl Margin="50">
<ItemsControl.Resources>
<Style x:Key="ScaleStyle" TargetType="TextBox">
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Grid.ZIndex" Value="1"/>
<Setter Property="RenderTransform">
<Setter.Value>
<ScaleTransform ScaleX="1.1" ScaleY="1.1"/>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</ItemsControl.Resources>
</ItemsControl>
Here is a small sample application. Contrary to my comment, we need the PreviewDragEnter event since the text box already has Drag/Drop support. In Window_Loaded, the application registers the event handlers. Then, in TextBox_PreviewDragEnter, the new style is set manually. We also store the old z-index to allow restoring it in TextBox_PreviewDragLeave.
<Window x:Class="WpfApp1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="350" Width="525" Loaded="Window_Loaded">
<StackPanel Margin="8">
<TextBox/>
<TextBox/>
<TextBox/>
<TextBox/>
</StackPanel>
</Window>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
//From https://stackoverflow.com/a/978352/1210053
public static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
{
if (depObj != null)
{
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
{
DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
if (child != null && child is T)
{
yield return (T)child;
}
foreach (T childOfChild in FindVisualChildren<T>(child))
{
yield return childOfChild;
}
}
}
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
foreach (var txt in FindVisualChildren<TextBox>(this))
{
txt.PreviewDragEnter += TextBox_PreviewDragEnter;
txt.PreviewDragLeave += TextBox_PreviewDragLeave;
txt.PreviewDrop += TextBox_PreviewDragLeave;
}
}
private Dictionary<TextBox, int> oldZIndex = new Dictionary<TextBox, int>();
private void TextBox_PreviewDragEnter(object sender, DragEventArgs e)
{
var txt = (TextBox)sender;
oldZIndex.Add(txt, Panel.GetZIndex(txt));
Panel.SetZIndex(txt, 1);
var scaleTransform = new ScaleTransform(1.1, 1.1, txt.ActualWidth / 2, txt.ActualHeight / 2);
txt.RenderTransform = scaleTransform;
}
private void TextBox_PreviewDragLeave(object sender, DragEventArgs e)
{
var txt = (TextBox)sender;
txt.RenderTransform = null;
Panel.SetZIndex(txt, oldZIndex[txt]);
oldZIndex.Remove(txt);
}
}
Approach from a different angle. Use the code behind to handle left click and drag.
Pseudo code...
If hover over textbox.text ==true
Textbox size = 300;
Then check the Grid location of the textbox. It should be allowed to columnspan over the other columns, while the rest of the controls stay fixed in their grid.row and grid.column locations.
I have defined a label with name and I'm trying to access it but no luck. Let me explain my problem with my code.
<ListView Name="gridListView" ItemsSource="{Binding... }">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="Focusable" Value="false"/>
</Style>
</ListView.ItemContainerStyle>
<ListView.ItemTemplate>
<DataTemplate>
<Border>
<StackPanel Orientation="Vertical">
<Label x:Name="vLabel" Content="{Binding VCValue}"/>
<ListView Name="checkBoxListView" ItemsSource="{Binding CList}">
<ListView.ItemTemplate>
<DataTemplate>
<CheckBox Margin="5" Click="CheckBox_Click" IsChecked="{Binding SelectedValue, Mode=TwoWay}" Content="{Binding Current, Mode=OneWay }"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackPanel>
</Border>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
In the above code, I have two listview, gridListView and checkBoxListView. Here, I want to access the label vLabel which is inside the datatemplate of gridListView when the one of the value in checkbox(which is inside checkBoxListView) is clicked.
I understand it can't be accessed directly as its within datatemplate so i tried below code as suggested in other forums but gridListView.SelectedIndex is always -1 so i know i'm not doing the right thing. When I just hardcoded gridListView.SelectedIndex to index 0, 1 or 2 its giving me the right value of vLabel so the below code will work if gridListView.SelectedIndex is correct.
private void CheckBox_Click(object sender, RoutedEventArgs e)
{
CheckBox chk =(CheckBox)sender;
int index = gridListView.Items.IndexOf(chk.DataContext);
ListViewItem item = gridListView.ItemContainerGenerator.ContainerFromIndex(gridListView.SelectedIndex) as ListViewItem;
if (item!=null)
{
//get the item's template parent
ContentPresenter templateParent = GetFrameworkElementByName<ContentPresenter>(item);
DataTemplate dataTemplate = gridListView.ItemTemplate;
if (dataTemplate != null && templateParent != null)
{
var lab = dataTemplate.FindName("vLabel", templateParent) as Label;
var v = lab.Content;
}
}
private static T GetFrameworkElementByName<T>(FrameworkElement referenceElement) where T : FrameworkElement
{
//I can post this function if need be
....
}
Appreciate any help that will help me access vLabel.
Thanks in advance
you are setting focusable to false, so you cant select the item by clicking. also the checkbox-checked happens before the selection, even if you were to set focusable to true, so selected index would still be -1.
you can find your label simply like this:
public Label FindLabel(CheckBox checkBox)
{
var listView = VisualTreeHelper.GetParent(checkBox);
while (listView.GetType() != typeof(ListView))
{
listView = VisualTreeHelper.GetParent(listView);
}
return (listView as FrameworkElement).FindName("vLabel") as Label;
}
but i suggest you tell us what you want to achieve, because this doesnt seem like a clean solution.
can you perhaps do this on your StackPanel:
<StackPanel CheckBox.Checked="CheckBox_Click" Orientation="Vertical">
and then access your two desired properties as following:
private void CheckBox_Click(object sender, RoutedEventArgs e)
{
var outerItem = (sender as FrameworkElement).DataContext;
var innerItem = (e.OriginalSource as FrameworkElement).DataContext;
}
and then do whatever you want to do?
Thank you for all your guidance. I did get hint from Milan's code to achieve solution for my issue. Here, I'm trying to get reference parent of listviewItem(i.e stackpanel) and then access its child. In my case, stack panels child at index 0 is Label and at index 1 is ListView. So then I go through visualtreehelper to get reference to its child at index 0 which is what i need access to. So here is the code snippet.
private void CheckBox_Click(object sender, RoutedEventArgs e)
{
CheckBox checkBox = (CheckBox)sender;
//to access parent of the checkbox
ListViewItem listViewItem =
GetVisualAncestor<ListViewItem>((DependencyObject)sender);
//to access parent of the listViewItem(which is parent of checkbox)
StackPanel stackPanel =
GetVisualAncestor<StackPanel>((DependencyObject)listViewItem);
int childCount = VisualTreeHelper.GetChildrenCount(stackPanel);
//to access child of stackpanel to access the current vLabel
var vValue = VisualTreeHelper.GetChild(stackPanel, 0) as Label;
}
private static T GetVisualAncestor<T>(DependencyObject o)where T : DependecyObject
{
...
}
I need to access the scrollviewer of a listview from the codebehind.
here is the definition of my listview
<ListView Grid.Row="1" ItemsSource="{Binding Path=SpecList, UpdateSourceTrigger=PropertyChanged}"
Name="mylistview"
ItemTemplate="{StaticResource SpecElementTemplate}"
Background="{StaticResource EnvLayout}"
ScrollViewer.HorizontalScrollBarVisibility="Visible"
ScrollViewer.VerticalScrollBarVisibility="Disabled"
ItemContainerStyle="{StaticResource MyStyle}"
BorderBrush="Blue"
BorderThickness="20"
Margin="-2">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
How can I get the scrollviewer?
Thank you
Andrea
There are several ways to get the ScrollViewer. Simplest solution is to get the the first child of the first child of the ListView. This means get the Border and the ScrollViewer inside this Border like described in
this answer:
// Get the border of the listview (first child of a listview)
Decorator border = VisualTreeHelper.GetChild(mylistview, 0) as Decorator;
// Get scrollviewer
ScrollViewer scrollViewer = border.Child as ScrollViewer;
A second way is to scan all childrens recursive to find the ScrollViewer. This is described in the answer by Matt Hamilton in this question. You can simply use this function to get the ScrollViewer.
ScrollViewer scrollViewer = GetChildOfType<ScrollViewer>(mylistview);
This second solution is much more generic and will also work if the template of your ListView was edited.
Use VisualTreeHelper class to access any child control.
Psudeo code to your case:
//Declare a scroll viewer object.
ScrollViewer sViewer = default(ScrollViewer );
//Start looping the child controls of your listview.
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(YOUR_LISTVIEW_OBJECT.VisualParent ); i++)
{
// Retrieve child visual at specified index value.
Visual childVisual = (Visual)VisualTreeHelper.GetChild(YOUR_LISTVIEW_OBJECT.VisualParent , i);
ScrollViewer sViewer = childVisual as ScrollViewer;
//You got your scroll viewer. Stop looping.
if (sViewer != null)
{
break;
}
}
I also suggest using the CollectionChanged event. In this code, the CollectionChanged event handler is added to the codebehind after the view model has been loaded. Then, each time the collection changes we scroll to the bottom of the listview. Here is an important point. The scrollviewer child of the list view might not yet be completely rendered when our events start firing. Hence we will get exceptions if we try to use the VisualTreeHelper.GetChild method. So, we have to first attempt to get the scrollviewer and then ignore its positioning if it is not yet available.
private void ReceivedItems_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
// Make sure the items source property in the viewmodel has some items
if (myViewModel.ReceivedItems.Count > 0)
{
var aScrollViewer = RcvdListView.GetChildOfType<ScrollViewer>();
// Make sure the scrollviewer exists before trying to position it
if (aScrollViewer != null)
{
aScrollViewer.ScrollToBottom();
}
}
}
Listview's ScrollViewer should be accessible after LayoutUpdated. You could hook on LayoutUpdated and then get if from Visual tree
private static void ListView_LayoutUpdated(object sender, EventArgs e)
{
var listview = (ListView)sender;
var viewer = listview.GetFirstChildOfType<ScrollViewer>();
}
public static T GetFirstChildOfType<T>(this DependencyObject dependencyObject) where T : DependencyObject
{
if (dependencyObject == null)
{
return null;
}
for (var i = 0; i < VisualTreeHelper.GetChildrenCount(dependencyObject); i++)
{
var child = VisualTreeHelper.GetChild(dependencyObject, i);
var result = (child as T) ?? GetFirstChildOfType<T>(child);
if (result != null)
{
return result;
}
}
return null;
}
I have multiples DataGrids disposed over a ScrollViewer.
These DataGrids have an "height: auto" property so that I can hide the scrollbar and view all the content.
The only problem is that the DataGrids takes the focus and so I can't scroll the ScrollViewer.
Is that a property to keep the focus on the ScrollViewer but also keeping the behaviour of the DataGrids (so I can select elements) ?
Thank you !
It's to late, but I resolved this problem in this manner:
I created the PreviewMouseWheel event for DataGrid
and manually scrolled the wrapping ScrollViewer
private void dgInvoicesItems_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
this.scrInvoice.ScrollToVerticalOffset(this.scrInvoice.ContentVerticalOffset - e.Delta);
}
I ran across this exact same issue except my scenario was a little bit more complicated. Instead of having DataGrid in a ScrollViewer, I had a bunch of UserControl (called ProductDataGrid and defined below) in my ScrollViewer:
ProductDataGrid.xaml:
<UserControl x:Class="My.Control.ProductDataGrid" ...>
<Grid>
<Grid.RowDefinitions>...</Grid.RowDefinitions>
<TextBlock x:Name="Header" Grid.Row="0" ... />
<DataGrid x:Name="ProductData" Grid.Row="1" ... />
</Grid>
</UserControl>
ProductPortfolioListView.xaml:
<Page ...
xmlns:my="clr-namespace:My.Control"
....>
<Grid>
<Grid.RowDefinitions>...</Grid.RowDefinitions>
<ScrollViewer x:Name="ProductScrollViewer">
<StackPanel>
<my:ProductDataGrid ... />
<my:ProductDataGrid ... />
<my:ProductDataGrid ... />
</StackPanel>
</ScrollViewer>
The solution provided by Livsi is spot on correct but my UserControl did not have access to my ScrollViewer, so here is my solution:
ProductPortfolioListView.xaml:
<Page ...
xmlns:my="clr-namespace:My.Control"
....>
<Grid>
<Grid.RowDefinitions>...</Grid.RowDefinitions>
<ScrollViewer x:Name="ProductScrollViewer">
<StackPanel>
<my:ProductDataGrid ...
PreviewMouseWheel="ProductDataGrid_PreviewMouseWheel" />
<my:ProductDataGrid ...
PreviewMouseWheel="ProductDataGrid_PreviewMouseWheel" />
<my:ProductDataGrid ...
PreviewMouseWheel="ProductDataGrid_PreviewMouseWheel" />
</StackPanel>
</ScrollViewer>
ProductPortfolioListView.xaml.cs:
void ProductDataGrid_PreviewMouseWheel(object sender, MouseWheelEventArgs args)
{
ProductScrollViewer.ScrollToVerticalOffset(ProductScrollViewer.ContentVerticalOffset - args.Delta;
args.Handled = true;
}
Note the beauty of this solution lies in the fact that I can separate my DataGrid from the Page that will hold them, so I achieve code isolation as well as less duplicated code. And even better, I absolutely utilize the fact that RoutedEvents keep propragating from the Source to all of its parents until someone handles it (which in my case is my ProductScrollViewer).
TopMouseScrollPriorityBehavior.TopMouseScrollPriority
You can simply set the following Attached Property to your ScrollViewer
public class TopMouseScrollPriorityBehavior
{
public static bool GetTopMouseScrollPriority(DependencyObject obj)
{
return (bool)obj.GetValue(TopMouseScrollPriorityProperty);
}
public static void SetTopMouseScrollPriority(DependencyObject obj, bool value)
{
obj.SetValue(TopMouseScrollPriorityProperty, value);
}
public static readonly DependencyProperty TopMouseScrollPriorityProperty =
DependencyProperty.RegisterAttached("TopMouseScrollPriority", typeof(bool), typeof(TopMouseScrollPriorityBehavior), new PropertyMetadata(false, OnPropertyChanged));
private static void OnPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var scrollViewer = d as ScrollViewer;
if (scrollViewer == null)
throw new InvalidOperationException($"{nameof(TopMouseScrollPriorityBehavior)}.{nameof(TopMouseScrollPriorityProperty)} can only be applied to controls of type {nameof(ScrollViewer)}");
if (e.NewValue == e.OldValue)
return;
if ((bool)e.NewValue)
scrollViewer.PreviewMouseWheel += ScrollViewer_PreviewMouseWheel;
else
scrollViewer.PreviewMouseWheel -= ScrollViewer_PreviewMouseWheel;
}
private static void ScrollViewer_PreviewMouseWheel(object sender, System.Windows.Input.MouseWheelEventArgs e)
{
var scrollViewer = (ScrollViewer)sender;
scrollViewer.ScrollToVerticalOffset(scrollViewer.VerticalOffset - e.Delta);
e.Handled = true;
}
}
Usage
<ScrollViewer b:TopMouseScrollPriorityBehavior.TopMouseScrollPriority="True" VerticalScrollBarVisibility="Auto" Margin="5" PanningMode="VerticalFirst">
<DataGrid ScrollViewer.PanningMode="None" ItemsSource="{Binding Items}" />
</ScrollViewer>
Where b: is the namespace that contains this behavior
Touch Support
To enable touch support you might also want to set ScrollViewer.PanningMode to None on your DataGrid and set the same property to VerticalFirst or other value on your top level ScrollViewer
Example
<ScrollViewer VerticalScrollBarVisibility="Auto" Margin="5" PanningMode="VerticalFirst">
<DataGrid ScrollViewer.PanningMode="None" ItemsSource="{Binding Items}" />
</ScrollViewer>
Try setting the CanContentScroll on the DataGrid to False like this:
<DataGrid ScrollViewer.CanContentScroll="False" ... />