XAML ListView Into ScrollView doesn't scroll [duplicate] - wpf

I have a usercontrol that has a scrollviewer, then a bunch of child controls like text boxes, radio buttons, and listboxes, etc inside of it. I can use the mouse wheel to scroll the parent scrollviewer until my mouse lands inside a listbox then, the mouse wheel events start going to the listbox.
Is there any way to have the listbox send those events back up to the parent control? Removing the listbox from within side the parent control like this question suggests (Mouse wheel not working when over ScrollViewer's child controls) isnt a solution.
I have tried
private void ListBox_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
e.Handled = true;
}
but that didnt work either.
Thanks

This can be accomplished via attached behaviors.
http://josheinstein.com/blog/index.php/2010/08/wpf-nested-scrollviewer-listbox-scrolling/
Edit:
Here is the linked solution:
"So instead I came up with the following IgnoreMouseWheelBehavior. Technically it’s not ignoring the MouseWheel, but it is “forwarding” the event back up and out of the ListBox. Check it."
/// <summary>
/// Captures and eats MouseWheel events so that a nested ListBox does not
/// prevent an outer scrollable control from scrolling.
/// </summary>
public sealed class IgnoreMouseWheelBehavior : Behavior<UIElement>
{
protected override void OnAttached( )
{
base.OnAttached( );
AssociatedObject.PreviewMouseWheel += AssociatedObject_PreviewMouseWheel ;
}
protected override void OnDetaching( )
{
AssociatedObject.PreviewMouseWheel -= AssociatedObject_PreviewMouseWheel;
base.OnDetaching( );
}
void AssociatedObject_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
e.Handled = true;
var e2 = new MouseWheelEventArgs(e.MouseDevice,e.Timestamp,e.Delta);
e2.RoutedEvent = UIElement.MouseWheelEvent;
AssociatedObject.RaiseEvent(e2);
}
}
And here’s how you would use it in XAML.
<ScrollViewer Name="IScroll">
<ListBox Name="IDont">
<i:Interaction.Behaviors>
<local:IgnoreMouseWheelBehavior />
</i:Interaction.Behaviors>
</ListBox>
</ScrollViewer>
Where the i namespace is:
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

The answer you have referenced is exactly what is causing your problem, the ListBox (which is composed of among other things a ScrollViewer) inside your ScrollViewer catches the MouseWheel event and handles it, preventing it from bubbling and thus the ScrollViewer has no idea the event ever occurred.
Use the following extremely simple ControlTemplate for your ListBox to demonstrate (note it does not have a ScrollViewer in it and so the MouseWheel event will not be caught) The ScrollViewer will still scroll with the mouse over the ListBox.
<UserControl.Resources>
<ControlTemplate x:Key="NoScroll">
<ItemsPresenter></ItemsPresenter>
</ControlTemplate>
</UserControl.Resources>
<ScrollViewer>
<SomeContainerControl>
<.... what ever other controls are inside your ScrollViewer>
<ListBox Template="{StaticResource NoScroll}"></ListBox>
<SomeContainerControl>
</ScrollViewer>
You do have the option of capturing the mouse when it enters the ScrollViewer though so it continues to receive all mouse events until the mouse is released, however this option would require you to delgate any further mouse events to the controls contained within the ScrollViewer if you want a response...the following MouseEnter MouseLeave event handlers will be sufficient.
private void ScrollViewerMouseEnter(object sender, MouseEventArgs e)
{
((ScrollViewer)sender).CaptureMouse();
}
private void ScrollViewerMouseLeave(object sender, MouseEventArgs e)
{
((ScrollViewer)sender).ReleaseMouseCapture();
}
Neither of the workarounds I have provided are really preferred however and I would suggest rethinking what you are actually trying to do. If you explain what you are trying to achieve in your question I'm sure you will get some more suggestions...

I followed Amanduh's approach to solve the same problem I had with multiple datagrids in a scrollviewer but in WPF:
public sealed class IgnoreMouseWheelBehavior
{
public static bool GetIgnoreMouseWheel(DataGrid gridItem)
{
return (bool)gridItem.GetValue(IgnoreMouseWheelProperty);
}
public static void SetIgnoreMouseWheel(DataGrid gridItem, bool value)
{
gridItem.SetValue(IgnoreMouseWheelProperty, value);
}
public static readonly DependencyProperty IgnoreMouseWheelProperty =
DependencyProperty.RegisterAttached("IgnoreMouseWheel", typeof(bool),
typeof(IgnoreMouseWheelBehavior), new UIPropertyMetadata(false, OnIgnoreMouseWheelChanged));
static void OnIgnoreMouseWheelChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
{
var item = depObj as DataGrid;
if (item == null)
return;
if (e.NewValue is bool == false)
return;
if ((bool)e.NewValue)
item.PreviewMouseWheel += OnPreviewMouseWheel;
else
item.PreviewMouseWheel -= OnPreviewMouseWheel;
}
static void OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
e.Handled = true;
var e2 = new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta)
{RoutedEvent = UIElement.MouseWheelEvent};
var gv = sender as DataGrid;
if (gv != null) gv.RaiseEvent(e2);
}
}

As Simon said, it's the ScrollViewer in the standard ListBox template that's catching the event. To bypass it you can provide your own template.
<ControlTemplate x:Key="NoWheelScrollListBoxTemplate" TargetType="ListBox">
<Border BorderThickness="{TemplateBinding Border.BorderThickness}" Padding="1,1,1,1" BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" Name="Bd" SnapsToDevicePixels="True">
<!-- This is the new control -->
<l:NoWheelScrollViewer Padding="{TemplateBinding Control.Padding}" Focusable="False">
<ItemsPresenter SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</l:NoWheelScrollViewer>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="UIElement.IsEnabled" Value="False">
<Setter TargetName="Bd" Property="Panel.Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />
</Trigger>
<Trigger Property="ItemsControl.IsGrouping" Value="True">
<Setter Property="ScrollViewer.CanContentScroll" Value="False" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
And the implementation for NoWheelScrollViewer is pretty simple.
public class NoWheelScrollViewer : ScrollViewer
{
protected override void OnMouseWheel(MouseWheelEventArgs e)
{
// Do nothing
}
}
Then, whenever you want a listbox to not handle the mouse wheel.
<ListBox Template="{StaticResource NoWheelScrollListBoxTemplate}">

I was trying to adapt Simon Fox's answer for a DataGrid. I found the the template hid my headers, and I never got the mouseLeave event by doing it in C#. This is ultimately what worked for me:
private void DataGrid_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
((DataGrid)sender).CaptureMouse();
}
private void DataGrid_MouseWheel(object sender, MouseWheelEventArgs e)
{
((DataGrid)sender).ReleaseMouseCapture();
}

A simple solution which worked for me is to override the inner control template to remove the scroll viewer (whichever required) like this
For example
I have a structure like this
ListView (a)
ListView (b)
ListView (c)
I wanted to bubble the mouse wheel scroll of (b) to (a), however wanted to keep the mouse wheel scroll of (c) available.
I simply overridden the Template of (b) like this. This allowed me to bubble contents of (b) except (c) to (a). Also, I can still scroll the contents of (c). If i want to remove even for (c) then i have to repeat the same step.
<ListView.Template>
<ControlTemplate>
<ItemsPresenter />
</ControlTemplate>
</ListView.Template>

A modified Simon Fox's solution if the original doesn't work:
public sealed class IgnoreMouseWheelBehavior : Behavior<UIElement>
{
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.PreviewMouseWheel += AssociatedObject_PreviewMouseWheel;
}
protected override void OnDetaching()
{
AssociatedObject.PreviewMouseWheel -= AssociatedObject_PreviewMouseWheel;
base.OnDetaching();
}
static void AssociatedObject_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
if (!(sender is DependencyObject))
{
return;
}
DependencyObject parent = VisualTreeHelper.GetParent((DependencyObject) sender);
if (!(parent is UIElement))
{
return;
}
((UIElement) parent).RaiseEvent(
new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta) { RoutedEvent = UIElement.MouseWheelEvent });
e.Handled = true;
}
}

You must listening PreviewMouseWheel from ScrollViewer (it works), but not from listbox.

Related

How to remove event handler that is assigned through style

I've created a WPF window. In that I've created style for a textbox which have size information as well as some eventsetters; Then, I've created some textboxes assigning the above style.
Now for one case I need to remove events of that textbox. But I cant do that.
Even though I do the following the event is not detached. It still there.
txt9.PreviewLostKeyboardFocus -= txt9_PreviewLostKeyboardFocus;
This occurs only when the event is attached in the style itself.
If it were within the TextBox control the event detaches fine.
My Code:
XAML:
<Window.Resources>
<ResourceDictionary>
<Style x:Key="txtStyle11" TargetType="TextBox">
<Setter Property="Width" Value="150"/>
<Setter Property="Height" Value="35"/>
<EventSetter Event="PreviewLostKeyboardFocus" Handler="txt9_PreviewLostKeyboardFocus"/>
</Style>
</ResourceDictionary>
</Window.Resources>
<Grid MinWidth="50">
<TextBox Style="{StaticResource txtStyle11}" x:Name="txt9"/>
</Grid>
CS:
public MainWindow()
{
txt9.PreviewLostKeyboardFocus -= txt9_PreviewLostKeyboardFocus;
}
Hi we cannot Unsubscribe events whcih are subscribed in EventSetter, because
internally EventSetter class becomes immutable and so the properties of the
EventSetter object cannot be modified. Below is the sample which I tried to
illustrate the same. This sample throws exception when we try to change the
property of setterbase class
public partial class MainWindow : Window
{
KeyboardFocusChangedEventHandler mydelegate, emptydelegate;
EventSetter eventSetter;
public MainWindow()
{
InitializeComponent();
emptydelegate = delegate(object sender, KeyboardFocusChangedEventArgs e)
{
};
mydelegate = delegate(object sender, KeyboardFocusChangedEventArgs e)
{
MessageBox.Show("My Own Event is still Unsubscribed");
};
eventSetter = new EventSetter();
eventSetter.Event = TextBox.PreviewLostKeyboardFocusEvent;
eventSetter.Handler = mydelegate;
Style myStyle = new System.Windows.Style(txt9.GetType());
myStyle.Setters.Add(eventSetter);
txt9.Style = myStyle;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
eventSetter.Handler= emptydelegate;
}
}

WPF disable mouse-wheel-scrolling on a ListView [duplicate]

I have a usercontrol that has a scrollviewer, then a bunch of child controls like text boxes, radio buttons, and listboxes, etc inside of it. I can use the mouse wheel to scroll the parent scrollviewer until my mouse lands inside a listbox then, the mouse wheel events start going to the listbox.
Is there any way to have the listbox send those events back up to the parent control? Removing the listbox from within side the parent control like this question suggests (Mouse wheel not working when over ScrollViewer's child controls) isnt a solution.
I have tried
private void ListBox_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
e.Handled = true;
}
but that didnt work either.
Thanks
This can be accomplished via attached behaviors.
http://josheinstein.com/blog/index.php/2010/08/wpf-nested-scrollviewer-listbox-scrolling/
Edit:
Here is the linked solution:
"So instead I came up with the following IgnoreMouseWheelBehavior. Technically it’s not ignoring the MouseWheel, but it is “forwarding” the event back up and out of the ListBox. Check it."
/// <summary>
/// Captures and eats MouseWheel events so that a nested ListBox does not
/// prevent an outer scrollable control from scrolling.
/// </summary>
public sealed class IgnoreMouseWheelBehavior : Behavior<UIElement>
{
protected override void OnAttached( )
{
base.OnAttached( );
AssociatedObject.PreviewMouseWheel += AssociatedObject_PreviewMouseWheel ;
}
protected override void OnDetaching( )
{
AssociatedObject.PreviewMouseWheel -= AssociatedObject_PreviewMouseWheel;
base.OnDetaching( );
}
void AssociatedObject_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
e.Handled = true;
var e2 = new MouseWheelEventArgs(e.MouseDevice,e.Timestamp,e.Delta);
e2.RoutedEvent = UIElement.MouseWheelEvent;
AssociatedObject.RaiseEvent(e2);
}
}
And here’s how you would use it in XAML.
<ScrollViewer Name="IScroll">
<ListBox Name="IDont">
<i:Interaction.Behaviors>
<local:IgnoreMouseWheelBehavior />
</i:Interaction.Behaviors>
</ListBox>
</ScrollViewer>
Where the i namespace is:
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
The answer you have referenced is exactly what is causing your problem, the ListBox (which is composed of among other things a ScrollViewer) inside your ScrollViewer catches the MouseWheel event and handles it, preventing it from bubbling and thus the ScrollViewer has no idea the event ever occurred.
Use the following extremely simple ControlTemplate for your ListBox to demonstrate (note it does not have a ScrollViewer in it and so the MouseWheel event will not be caught) The ScrollViewer will still scroll with the mouse over the ListBox.
<UserControl.Resources>
<ControlTemplate x:Key="NoScroll">
<ItemsPresenter></ItemsPresenter>
</ControlTemplate>
</UserControl.Resources>
<ScrollViewer>
<SomeContainerControl>
<.... what ever other controls are inside your ScrollViewer>
<ListBox Template="{StaticResource NoScroll}"></ListBox>
<SomeContainerControl>
</ScrollViewer>
You do have the option of capturing the mouse when it enters the ScrollViewer though so it continues to receive all mouse events until the mouse is released, however this option would require you to delgate any further mouse events to the controls contained within the ScrollViewer if you want a response...the following MouseEnter MouseLeave event handlers will be sufficient.
private void ScrollViewerMouseEnter(object sender, MouseEventArgs e)
{
((ScrollViewer)sender).CaptureMouse();
}
private void ScrollViewerMouseLeave(object sender, MouseEventArgs e)
{
((ScrollViewer)sender).ReleaseMouseCapture();
}
Neither of the workarounds I have provided are really preferred however and I would suggest rethinking what you are actually trying to do. If you explain what you are trying to achieve in your question I'm sure you will get some more suggestions...
I followed Amanduh's approach to solve the same problem I had with multiple datagrids in a scrollviewer but in WPF:
public sealed class IgnoreMouseWheelBehavior
{
public static bool GetIgnoreMouseWheel(DataGrid gridItem)
{
return (bool)gridItem.GetValue(IgnoreMouseWheelProperty);
}
public static void SetIgnoreMouseWheel(DataGrid gridItem, bool value)
{
gridItem.SetValue(IgnoreMouseWheelProperty, value);
}
public static readonly DependencyProperty IgnoreMouseWheelProperty =
DependencyProperty.RegisterAttached("IgnoreMouseWheel", typeof(bool),
typeof(IgnoreMouseWheelBehavior), new UIPropertyMetadata(false, OnIgnoreMouseWheelChanged));
static void OnIgnoreMouseWheelChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
{
var item = depObj as DataGrid;
if (item == null)
return;
if (e.NewValue is bool == false)
return;
if ((bool)e.NewValue)
item.PreviewMouseWheel += OnPreviewMouseWheel;
else
item.PreviewMouseWheel -= OnPreviewMouseWheel;
}
static void OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
e.Handled = true;
var e2 = new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta)
{RoutedEvent = UIElement.MouseWheelEvent};
var gv = sender as DataGrid;
if (gv != null) gv.RaiseEvent(e2);
}
}
As Simon said, it's the ScrollViewer in the standard ListBox template that's catching the event. To bypass it you can provide your own template.
<ControlTemplate x:Key="NoWheelScrollListBoxTemplate" TargetType="ListBox">
<Border BorderThickness="{TemplateBinding Border.BorderThickness}" Padding="1,1,1,1" BorderBrush="{TemplateBinding Border.BorderBrush}" Background="{TemplateBinding Panel.Background}" Name="Bd" SnapsToDevicePixels="True">
<!-- This is the new control -->
<l:NoWheelScrollViewer Padding="{TemplateBinding Control.Padding}" Focusable="False">
<ItemsPresenter SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" />
</l:NoWheelScrollViewer>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="UIElement.IsEnabled" Value="False">
<Setter TargetName="Bd" Property="Panel.Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" />
</Trigger>
<Trigger Property="ItemsControl.IsGrouping" Value="True">
<Setter Property="ScrollViewer.CanContentScroll" Value="False" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
And the implementation for NoWheelScrollViewer is pretty simple.
public class NoWheelScrollViewer : ScrollViewer
{
protected override void OnMouseWheel(MouseWheelEventArgs e)
{
// Do nothing
}
}
Then, whenever you want a listbox to not handle the mouse wheel.
<ListBox Template="{StaticResource NoWheelScrollListBoxTemplate}">
I was trying to adapt Simon Fox's answer for a DataGrid. I found the the template hid my headers, and I never got the mouseLeave event by doing it in C#. This is ultimately what worked for me:
private void DataGrid_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
((DataGrid)sender).CaptureMouse();
}
private void DataGrid_MouseWheel(object sender, MouseWheelEventArgs e)
{
((DataGrid)sender).ReleaseMouseCapture();
}
A simple solution which worked for me is to override the inner control template to remove the scroll viewer (whichever required) like this
For example
I have a structure like this
ListView (a)
ListView (b)
ListView (c)
I wanted to bubble the mouse wheel scroll of (b) to (a), however wanted to keep the mouse wheel scroll of (c) available.
I simply overridden the Template of (b) like this. This allowed me to bubble contents of (b) except (c) to (a). Also, I can still scroll the contents of (c). If i want to remove even for (c) then i have to repeat the same step.
<ListView.Template>
<ControlTemplate>
<ItemsPresenter />
</ControlTemplate>
</ListView.Template>
A modified Simon Fox's solution if the original doesn't work:
public sealed class IgnoreMouseWheelBehavior : Behavior<UIElement>
{
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.PreviewMouseWheel += AssociatedObject_PreviewMouseWheel;
}
protected override void OnDetaching()
{
AssociatedObject.PreviewMouseWheel -= AssociatedObject_PreviewMouseWheel;
base.OnDetaching();
}
static void AssociatedObject_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
if (!(sender is DependencyObject))
{
return;
}
DependencyObject parent = VisualTreeHelper.GetParent((DependencyObject) sender);
if (!(parent is UIElement))
{
return;
}
((UIElement) parent).RaiseEvent(
new MouseWheelEventArgs(e.MouseDevice, e.Timestamp, e.Delta) { RoutedEvent = UIElement.MouseWheelEvent });
e.Handled = true;
}
}
You must listening PreviewMouseWheel from ScrollViewer (it works), but not from listbox.

MVVM C# WPF binding mouse double click

I want to copy the content of one text box to another text box by clicking the mouse.
How do I bind a mouse click event?
This sample is for RightClick, but you can adjust the event according to your needs:
<TextBox>
<TextBox.InputBindings>
<MouseBinding Gesture="RightClick" Command="{Binding YourCommand}" />
</TextBox.InputBindings>
</TextBox>
Edit: I uploaded on my SkyDrive a sample app that illustrates how to use this method in order to achieve exactly what you need. Please be advised that it will only work for .NET Framework 4+
Want to add a behavior to a control ? Just use the Ramora pattern !
Hope this helps
Use this code for TreeView
<TreeView commandBehaviors:MouseDoubleClick.Command="{Binding YourCommand}"
commandBehaviors:MouseDoubleClick.CommandParameter="{Binding}"
.../>
Use this code for TreeViewItem
<TreeView ItemsSource="{Binding Projects}">
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="commandBehaviors:MouseDoubleClick.Command"
Value="{Binding YourCommand}"/>
<Setter Property="commandBehaviors:MouseDoubleClick.CommandParameter"
Value="{Binding}"/>
</Style>
</TreeView.ItemContainerStyle>
</TreeView>
Use this code to create a new behavior MouseDoubleClick
public class MouseDoubleClick
{
public static DependencyProperty CommandProperty =
DependencyProperty.RegisterAttached("Command",
typeof(ICommand),
typeof(MouseDoubleClick),
new UIPropertyMetadata(CommandChanged));
public static DependencyProperty CommandParameterProperty =
DependencyProperty.RegisterAttached("CommandParameter",
typeof(object),
typeof(MouseDoubleClick),
new UIPropertyMetadata(null));
public static void SetCommand(DependencyObject target, ICommand value)
{
target.SetValue(CommandProperty, value);
}
public static void SetCommandParameter(DependencyObject target, object value)
{
target.SetValue(CommandParameterProperty, value);
}
public static object GetCommandParameter(DependencyObject target)
{
return target.GetValue(CommandParameterProperty);
}
private static void CommandChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
{
Control control = target as Control;
if (control != null)
{
if ((e.NewValue != null) && (e.OldValue == null))
{
control.MouseDoubleClick += OnMouseDoubleClick;
}
else if ((e.NewValue == null) && (e.OldValue != null))
{
control.MouseDoubleClick -= OnMouseDoubleClick;
}
}
}
private static void OnMouseDoubleClick(object sender, RoutedEventArgs e)
{
Control control = sender as Control;
ICommand command = (ICommand)control.GetValue(CommandProperty);
object commandParameter = control.GetValue(CommandParameterProperty);
command.Execute(commandParameter);
}
}
It sounds like you are inventing a new behaviour for your textbox :)
I would just consider if the users of your program understands and likes this behaviour.
Maybe it is easier to understand the funcionality if it is just a button you have to click - it is also faster to implement :)
I think you could bind mouse gestures to commands. Take a look at this: http://www.thejoyofcode.com/Invoking_a_Command_on_a_Double_Click_or_other_Mouse_Gesture.aspx
I'm not sure what exactly you're wanting to bind to.
There is no readily available MouseClick event as far as i'm aware.
the Click event as you'd find on a Button is inherited from ButtonBase and is not readily available on most controls.
MouseDoubleClick is inherited from Control and available on anythning deriving from it.
in your example it sounds like a simple Button with its Click event handled might do the trick.
To bind to the click event, you just need to specify the event handler for the event in the Button.
Something like:
XAML:
<TextBox Name=TextBoxOne />
<TextBox Name=TextBoxTwo />
<Button Click="CopyTextButton_Click"/>
And in your code behind:
void CopyTextButton_Click(object sender, RoutedEventArgs e)
{
//Copy the text and anything else you need done
}
Otherwise if this is a more specialised scenario, you might want to investigate using a UserControl or as AndrewS answered above, a Command.
Hope it helps.
You can easily do this by creating a new behavior.
<TextBox
MouseDoubleClick="SelectAddress"
GotKeyboardFocus="SelectAddress"
PreviewMouseLeftButtonDown="SelectivelyIgnoreMouseButton" />
Here's the code behind:
private void SelectAddress(object sender, RoutedEventArgs e)
{
TextBox tb = (sender as TextBox);
if (tb != null)
{
tb.SelectAll();
}
}
private void SelectivelyIgnoreMouseButton(object sender,
MouseButtonEventArgs e)
{
TextBox tb = (sender as TextBox);
if (tb != null)
{
if (!tb.IsKeyboardFocusWithin)
{
e.Handled = true;
tb.Focus();
}
}
}
Please update this snippet according to your need.

WPF TreeView - How to scroll so expanded branch is visible

When I expand items in my treeview so that scrolling is necessary, a scrollbar appears. However, it doesn't scroll down for the newly expanded branch of items - they get cropped by the bottom of the control. So as I continue expanding items at the bottom of the tree, I have to keep manually scrolling down to see the new children. Anyone have a suggestion for how make it automatically scroll to show the newly expanded items?
You can use a simple EventSetter in TreeViewItem style to invoke an event handler when the item is selected. Then call BringIntoView for the item.
<TreeView >
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<EventSetter Event="Selected" Handler="TreeViewSelectedItemChanged" />
</Style>
</TreeView.ItemContainerStyle>
</TreeView>
private void TreeViewSelectedItemChanged(object sender, RoutedEventArgs e)
{
TreeViewItem item = sender as TreeViewItem;
if (item != null)
{
item.BringIntoView();
e.Handled = true;
}
}
On the TreeView, handle the TreeViewItem.Expanded event (you can do this at the TreeView level because of event bubbling). In the Expanded handler, call BringIntoView on the TreeViewItem that raised the event.
You may need a bit of trial and error to get hold of the TreeViewItem in your event handler code. I think (haven't checked) that the sender argument to your Expanded event handler will be the TreeView (since that's where the event handler is attached) rather than the TreeViewItem. And the e.Source or e.OriginalSource may be an element in the TreeViewItem's data template. So you may need to use VisualTreeHelper to walk up the visual tree to find the TreeViewItem. But if you use the debugger to inspect the sender and the RoutedEventArgs this should be trivial to figure out.
(If you're able to get this working and want to bundle it up so you don't have to attach the same event handler to every TreeView, it should be easy to encapsulate it as an attached behaviour which will allow you to apply it declaratively, including via a Style.)
Use a dependency property on an IsSelected trigger:
<Style TargetType="{x:Type TreeViewItem}">
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="commands:TreeViewItemBehavior.BringIntoViewWhenSelected" Value="True" />
</Trigger>
</Style.Triggers>
Here's the code for the dependency property:
public static bool GetBringIntoViewWhenSelected(TreeViewItem treeViewItem)
{
return (bool)treeViewItem.GetValue(BringIntoViewWhenSelectedProperty);
}
public static void SetBringIntoViewWhenSelected(TreeViewItem treeViewItem, bool value)
{
treeViewItem.SetValue(BringIntoViewWhenSelectedProperty, value);
}
public static readonly DependencyProperty BringIntoViewWhenSelectedProperty =
DependencyProperty.RegisterAttached("BringIntoViewWhenSelected", typeof(bool),
typeof(TreeViewItemBehavior), new UIPropertyMetadata(false, OnBringIntoViewWhenSelectedChanged));
static void OnBringIntoViewWhenSelectedChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs e)
{
TreeViewItem item = depObj as TreeViewItem;
if (item == null)
return;
if (e.NewValue is bool == false)
return;
if ((bool)e.NewValue)
item.BringIntoView();
}
Thanks to itowlson's answer, here's the expanded event handler code that works for both of my trees
private static void Tree_Expanded(object sender, RoutedEventArgs e)
{
// ignore checking, assume original source is treeviewitem
var treeViewItem = (TreeViewItem)e.OriginalSource;
var count = VisualTreeHelper.GetChildrenCount(treeViewItem);
for (int i = count - 1; i >= 0; --i)
{
var childItem = VisualTreeHelper.GetChild(treeViewItem, i);
((FrameworkElement)childItem).BringIntoView();
}
// do NOT call BringIntoView on the actual treeviewitem - this negates everything
//treeViewItem.BringIntoView();
}
I modified Jared's answer in combination with the strategy from here: https://stackoverflow.com/a/42238409/2477582
The main advantage is that there aren't n calls of BringIntoView() for n childs. There is only one call of BringIntoView for an area that covers all of the child's heights.
Additionally, the purpose of the referred topic is realized as well. But this part may be removed, if unwanted.
/// <summary>Prevents automatic horizontal scrolling, while preserving automatic vertical scrolling and other side effects</summary>
/// <remarks>Source: https://stackoverflow.com/a/42238409/2477582 </remarks>
private void TreeViewItem_RequestBringIntoView(object sender, RequestBringIntoViewEventArgs e)
{
// Ignore re-entrant calls
if (m_SuppressRequestBringIntoView)
return;
// Cancel the current scroll attempt
e.Handled = true;
// Call BringIntoView using a rectangle that extends into "negative space" to the left of our
// actual control. This allows the vertical scrolling behaviour to operate without adversely
// affecting the current horizontal scroll position.
m_SuppressRequestBringIntoView = true;
try
{
TreeViewItem tvi = sender as TreeViewItem;
if (tvi != null)
{
// take care of children
int ll_ChildCount = VisualTreeHelper.GetChildrenCount(tvi);
double ll_Height = tvi.ActualHeight;
if (ll_ChildCount > 0)
{
FrameworkElement ll_LastChild = VisualTreeHelper.GetChild(tvi, ll_ChildCount - 1) as FrameworkElement;
ll_Height += ll_ChildCount * ll_LastChild.ActualHeight;
}
Rect newTargetRect = new Rect(-1000, 0, tvi.ActualWidth + 1000, ll_Height);
tvi.BringIntoView(newTargetRect);
}
}
catch (Exception ex)
{
m_Log.Debug("Error in TreeViewItem_RequestBringIntoView: " + ex.ToString());
}
m_SuppressRequestBringIntoView = false;
}
The above solution works together with this:
/// <summary>Correctly handle programmatically selected items (needed due to the custom implementation of TreeViewItem_RequestBringIntoView)</summary>
/// <remarks>Source: https://stackoverflow.com/a/42238409/2477582 </remarks>
private void TreeViewItem_Selected(object sender, RoutedEventArgs e)
{
((TreeViewItem)sender).BringIntoView();
e.Handled = true;
}
This part takes care of toggling the elements at each click:
/// <summary>Support for single click toggle</summary>
private void TreeViewItem_MouseUp(object sender, MouseButtonEventArgs e)
{
TreeViewItem tvi = null;
// Source may be TreeViewItem directly, or be a ContentPresenter
if (e.Source is TreeViewItem)
{
tvi = e.Source as TreeViewItem;
}
else if (e.Source is ContentPresenter)
{
tvi = (e.Source as ContentPresenter).TemplatedParent as TreeViewItem;
}
if (tvi == null || e.Handled) return;
tvi.IsExpanded = !tvi.IsExpanded;
e.Handled = true;
}
Finally the XAML part:
<TreeView>
<TreeView.ItemContainerStyle>
<Style TargetType="TreeViewItem">
<EventSetter Event="RequestBringIntoView" Handler="TreeViewItem_RequestBringIntoView" />
<EventSetter Event="Selected" Handler="TreeViewItem_Selected" />
</Style>
</TreeView.ItemContainerStyle>
</TreeView>
A simple event listener on the tree worked for me:
<TreeView Margin="10,40,10,10" Grid.Column="0" x:Name="treeView" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" SelectedItemChanged="TreeView_SelectedItemChanged" />
private void TreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e) {
if (e.NewValue == null)
return;
((TreeViewItem)e.NewValue).BringIntoView();
}

Is faking a WPF mouseover possible?

I have a data template with a textbox and a button with some styles on it. I would like to have the button show the mouse over state when focus is on the textbox beside it. Is this possible?
I figure it would involve something like this. I can get the textbox through use of FindVisualChild and FindName. Then I can set the GotFocus event on the textbox to do something.
_myTextBox.GotFocus += new RoutedEventHandler(TB_GotFocus);
Here in TB_GotFocus I'm stuck. I can get the button I want to show the mouse over state of, but I don't know what event to send to it. MouseEnterEvent isn't allowed.
void TB_GotFocus(object sender, RoutedEventArgs e)
{
ContentPresenter myContentPresenter = FindVisualChild<ContentPresenter>(this.DataTemplateInstance);
DataTemplate template = myContentPresenter.ContentTemplate;
Button _button= template.FindName("TemplateButton", myContentPresenter) as Button;
_button.RaiseEvent(new RoutedEventArgs(Button.MouseEnterEvent));
}
I don't think it's possible to fake the event but you can force the button to render itself as if it had MouseOver.
private void tb_GotFocus(object sender, RoutedEventArgs e)
{
// ButtonChrome is the first child of button
DependencyObject chrome = VisualTreeHelper.GetChild(button, 0);
chrome.SetValue(Microsoft.Windows.Themes.ButtonChrome.RenderMouseOverProperty, true);
}
private void tb_LostFocus(object sender, RoutedEventArgs e)
{
// ButtonChrome is the first child of button
DependencyObject chrome = VisualTreeHelper.GetChild(button, 0);
chrome.ClearValue(Microsoft.Windows.Themes.ButtonChrome.RenderMouseOverProperty);
}
you need to reference PresentationFramework.Aero.dlll for this to work and then it will only work on Vista for the Aero theme.
If you want it to work for other themes you should make a custom controltemplate for each of the theme you want to support.
See http://blogs.msdn.com/llobo/archive/2006/07/12/663653.aspx for tips
As a follow up to jesperll's comment, I think you can get around making a custom template for each theme by dynamically setting the style to the one you want / null.
Here is my window, with the style defined (but not set to anything).
<Window x:Class="WpfApplication.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication"
Title="Window1" Height="300" Width="300">
<Window.Resources>
<Style TargetType="{x:Type Button}" x:Key="MouseOverStyle">
<Setter Property="Background">
<Setter.Value>Green</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<Grid Height="30">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="3*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBox x:Name="MyTextBox" Grid.Column="0" Text="Some Text" Margin="2" GotFocus="TextBox_GotFocus" LostFocus="MyTextBox_LostFocus"/>
<Button x:Name="MyButton" Grid.Column="1" Content="Button" Margin="2" MouseEnter="Button_MouseEnter" MouseLeave="Button_MouseLeave" />
</Grid>
Instead of setting the style via triggers in the template, you can use events in your .cs file like so:
...
public partial class Window1 : Window
{
Style mouseOverStyle;
public Window1()
{
InitializeComponent();
mouseOverStyle = (Style)FindResource("MouseOverStyle");
}
private void TextBox_GotFocus(object sender, RoutedEventArgs e) { MyButton.Style = mouseOverStyle; }
private void MyTextBox_LostFocus(object sender, RoutedEventArgs e) { MyButton.Style = null; }
private void Button_MouseEnter(object sender, MouseEventArgs e) { ((Button)sender).Style = mouseOverStyle; }
private void Button_MouseLeave(object sender, MouseEventArgs e) { ((Button)sender).Style = null; }
}
You get a reference to the style in the constructor and then dynamically set it / unset it. This way, you can define what you want your style to look like in Xaml, and you don't have to rely on any new dependencies.

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