My mouse wheel does not work when putting a ListBox in a ScrollViewer.
Does the ListBox somehow "steal" this event?
<ScrollViewer VerticalScrollBarVisibility="Auto" Style="{StaticResource myStyle}">
<ListBox>
<ListBoxItem>Test 1</ListBoxItem>
<ListBoxItem>Test 2</ListBoxItem>
<ListBoxItem>Test 3</ListBoxItem>
<ListBoxItem>Test 4</ListBoxItem>
<ListBoxItem>Test 5</ListBoxItem>
<ListBoxItem>Test 6</ListBoxItem>
<ListBoxItem>Test 7</ListBoxItem>
</ListBox>
</ScrollViewer>
Edit: as requested by Joel, added the reason why I did this..
I did this because I don't like what the ListBox's internal ScrollViewer does with my layout. I have a background image, and on top of that a ListBox as shown here:
alt text http://robbertdam.nl/share/1.png
Now when the scrollbar appears, the following happens:
alt text http://robbertdam.nl/share/2.png
I've created a Style for a ScrollViewer that shows the scroll bar on top of the ListBox item's content. In the ListBox item's datatemplate I've reserved some space for the scrollbar to appear.
Thanks,
Robbert Dam
Firstly, I think you need to elaborate on what your limitations are and what you're trying to achieve. Without that, I can only explain why what you're doing isn't working. Somebody may even have a better idea about how to get the result you're after.
If you put ListBox inside a ScrollViewer, then the control template for ListBox still has its own ScrollViewer inside. When the mouse cursor is over the ListBox and you scroll the mousewheel, that event bubbles up until it reaches the ScrollViewer that's part of ListBox. That one handles it by scrolling and marks the event as handled, so then the ScrollViewer you put the ListBox inside of ignores the event.
If you make the ListBox taller and narrower than the outer ScrollViewer, and give it enough items so that the ListBox itself can scroll the items, you'll see 2 vertical scroll bars: 1 in the ListBox, and 1 outside the ListBox for your outer ScrollViewer. When the mouse cursor is inside the ListBox, the ListBox will scroll the items with its internal ScrollViewer, and its Border will stay in place. When the mouse cursor is outside the ListBox and inside the outer ScrollViewer, that ScrollViewer will scroll its contents -- the ListBox -- which you can verify by noting that the ListBox's Border changes position.
If you want an outer ScrollViewer to scroll the entire ListBox control (including the Border and not just the items), you'll need to re-style the ListBox so that it does not have an internal ScrollViewer, but you'll also need to make sure it automatically gets bigger according to its items.
I don't recommend this approach for a couple reasons. It might make sense if there are other controls inside the ScrollViewer along with the ListBox, but your sample does not indicate that. Also, if you're going to have a lot of items in the ListBox, you'll be creating ListBoxItems for every single one, eliminating any advantage that the default, non-re-styled ListBox gives you due to the default VirtualizingStackPanel.
Please let us know what your actual requirements are.
Edit: Ok, now I have a little better idea, with the addition of those images. The effect you're getting is that when there are enough items to scroll and the scrollbar appears, the available area has to shrink a bit horizontally because the ScrollViewer's template uses a Grid. These seem to be your options, in order of lesser-to-better:
Re-style the ListBox to not have a ScrollViewer and use your re-styled ScrollViewer outside the ListBox. You'd then also have to force the ListBox to also be tall enough to show every item in that same Style, and now you've lost UI virtualization. If you're going to be showing hundreds of items in the list, you definitely don't want to lose that.
Re-style the ListBox and set the ControlTemplate to use a ScrollViewer with the style you already created for it that puts the scrollbar over the content rather than in a separate column. This one's ok (ListBox gets to limit its height and use a VirtualizingStackPanel, yay), but as you said, it necessitates awareness of that in your DataTemplate.
Re-style the ScrollViewer to leave space for vertical scrollbar even when it is not visible. Here's what this option looks like:
By default, ScrollViewer uses 2 columns in a Grid equivalent to this:
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
So the Width of the scrollbar's column is 0 when the scrollbar is not visible since Width="Auto". To leave space for the scrollbar even when it is hidden, we bind the Width of that column to the Width of the vertical scroll bar:
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition
Width="{Binding ElementName=PART_VerticalScrollBar, Path=Width}" />
</Grid.ColumnDefinitions>
So now the ControlTemplate in the custom Style for ScrollViewer might look like this:
<ControlTemplate
TargetType="{x:Type ScrollViewer}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition
Width="{Binding ElementName=PART_VerticalScrollBar, Path=Width}" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition
Height="Auto" />
</Grid.RowDefinitions>
<ScrollContentPresenter />
<ScrollBar
Grid.Column="1"
Name="PART_VerticalScrollBar"
Value="{TemplateBinding VerticalOffset}"
Maximum="{TemplateBinding ScrollableHeight}"
ViewportSize="{TemplateBinding ViewportHeight}"
Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}" />
<ScrollBar
Name="PART_HorizontalScrollBar"
Orientation="Horizontal"
Grid.Row="1"
Value="{TemplateBinding HorizontalOffset}"
Maximum="{TemplateBinding ScrollableWidth}"
ViewportSize="{TemplateBinding ViewportWidth}"
Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}" />
</Grid>
</ControlTemplate>
You could even make the content column a fixed size and the scrollbar column Width="*", which might work better in the long run if your image is not stretched. Now the DataTemplate does not have to compenstate for the width of a scrollbar, as it gets a consistent area to use whether the scrollbar is visible or not.
You'll probably want to check out the rest of the example ControlTemplate for ScrollViewer, but those examples are not the default styles. Note that the example puts the vertical scrollbar on the left! Also note the comment at the bottom about ContentScrollPresenter.
I was dealing with the same issue. I set the ListBox.ItemsPanel Property, without any ScrollViewer:
<ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
<ListBox>
<ListBox.Template>
<ControlTemplate TargetType="ItemsControl">
<Border>
<ItemsPresenter />
</Border>
</ControlTemplate>
</ListBox.Template>
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel />
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<\ListBox>
<\ScrollViewer>
Hope this helps.
see this link for another answer:Scroll in ScrollViewer when mouse over ListBox
Hello, I think you can handle the whole ListBox’s PreviewMouseWheel event. This will also affect individual items as long as you don’t handle each item’s
PreviewMouseWheel and mark the event as handled:
private void ListBox_PreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
if (e.Delta < 0)
{
scrollViewer1.LineDown();
}
else
{
scrollViewer1.LineUp();
}
}
If you just want to make work the mouse scrolling and don't need a style for the ScrollViewer:
Remove the outer ScrollViewer.
Use the attached properties of the ScrollViewer, which is inside of the ListBox.
See first two lines of this example:
<ListBox ScrollViewer.VerticalScrollBarVisibility="Auto"
ScrollViewer.HorizontalScrollBarVisibility="Auto">
<ListBoxItem>Test 1</ListBoxItem>
<ListBoxItem>Test 2</ListBoxItem>
<ListBoxItem>Test 3</ListBoxItem>
<ListBoxItem>Test 4</ListBoxItem>
<ListBoxItem>Test 5</ListBoxItem>
<ListBoxItem>Test 6</ListBoxItem>
<ListBoxItem>Test 7</ListBoxItem>
</ListBox>
Related
I have got the following XAML:
<StackPanel HorizontalAlignment="Center">
<Image Name="logo" Source="logo.png" Margin="0,0,0,50"/>
<ScrollViewer>
<Dashboard_Control:AlignableWrapPanel x:Name="wrapPanel"/>
</ScrollViewer>
<TextBlock FontWeight="Bold" HorizontalAlignment="Center" x:Name="txtBottomText"></TextBlock>
</StackPanel>
I would like that the wrapPanel is scrollable only, so that the txtBottomText control will always be at the bottom as you scroll, and the logo image control will always be at the top - essentially only allowing the wrapPanel to be scrollable.
I have tried adding a ScrollViewer as shown above, however it never shows. I even tried adding a property to always have the vertical scrollbar, however it appears without letting me scroll (the scrollbar is disabled).
I suspect that this is because my wrapPanel's content is dynamically generated at run-time like so:
wrapPanel.Children.Add(content);
Any ideas what I can do to fix this?
It's not because of your wrapPanel's content. but because you're using a StackPanel to contain everything.
StackPanels grow indefinitely in the direction determined by their Orientation property. By default, that's vertically.
In your case, that makes the ScrollViewer "think" it has enough available space to stretch itself to accomodate its content, instead of activating the scroll bars. So it simply gets bigger as the WrapPanel inside gets bigger, pushing the TextBlock down.
To avoid this, you need to use a different Panel that is able to properly assign the available space to each control. Like a Grid.
<Grid HorizontalAlignment="Center">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Image Name="logo" Source="logo.png" Margin="0,0,0,50"/>
<ScrollViewer Grid.Row="1">
<Dashboard_Control:AlignableWrapPanel x:Name="wrapPanel"/>
</ScrollViewer>
<TextBlock Grid.Row="2" FontWeight="Bold" HorizontalAlignment="Center" x:Name="txtBottomText"></TextBlock>
</Grid>
I usually say that StackPanels tend to be overused :P They're practical and easy to use, but they have a bunch of quirks and limitations that make them not suitable for many situations, like this one.
EDIT: Make sure, also, that the Grid is not contained inside another vertical StackPanel, a Grid row with Height set to Auto, or something like that.
If the Height of your WrapPanel exceeds the height of the control or window where you have put the controls, the Textblock below the Wrap Panel inside the Stack Panel is put after the Wrap panel and so it is below the scroll area.
To be able to leave the Textblock always visible you have two means:
1) limit the height of your Wrap panel
2) Use a container like a Grid with 3 rows instead of the stack panel and put the Row Heights of the Grid respectively to
Auto, *, Auto so that the image on top and the textblock on bottom use the space of their content and the Scroll panel uses all the space remaining
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Image Grid.Row ="0" Source="myimage.jpg" />
<ScrollViewer Grid.Row="1">
<WrapPanel Height="1200" Width="600">
<TextBlock>Ciao sono io</TextBlock>
</WrapPanel>
</ScrollViewer>
<TextBox Grid.Row="2" TextWrapping="Wrap" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Text="IO c'ero" />
</Grid>
You have to set a fixed heigh to your scrollviewer - if not, the scrollviewer takes as much space as he needs, in order to show the complete content of its children.
Solutions:
Set the Height property of your scollviewer
Use a grid instead of a stackpanel an set the first and third rowheight to auto
in a WPF window I have a TextBox inside a ScrollViewer:
<ScrollViewer ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" ScrollViewer.CanContentScroll="True" MaxHeight="160" Grid.Column="1" Grid.Row="0">
<TextBox MinHeight="80" Name="generalLog"/>
</ScrollViewer>
With an empty text it looks like this.
When the text gets to long or contains too many lines, the scrollbars appear, as they should. But as the TextBox is wrapped inside the ScrollViewer, the TextBox gets bigger and its border (default style) gets hidden on the sides:
Link to Screenshot because I can't embed pictures
As you can see, the border is not visible on the left side.
Is there any way to make the ScrollViewer appear inside the TextBox? Or make the ScrollViewer have a border like the TextBox and hide the TextBox one, which would probably look the way I want.
Thanks so much.
Wrap the Scrollviewer with a border and set Textbox borderbrush="transparent" ?
<Border>
<ScrollViewer ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" ScrollViewer.CanContentScroll="True" MaxHeight="160" Grid.Column="1" Grid.Row="0">
<TextBox BorderBrush="transparent" MinHeight="80" Name="generalLog"/>
</ScrollViewer>
</Border>
I have a grid of controls, where each editable control (checkbox, combobox, etc.) has an associated label. I want to share a tooltip between the label and its control.
Now this is something that I have accomplished by using BindableToolTips: I simply define the ToolTip in my XAML resources, and then set the same ToolTip object individually on the label and the control.
Code:
<TextBlock Grid.Row="0"
Grid.Column="0"
ToolTipService.PlacementTarget="{Binding ElementName=ExampleControl}"
Utilities:ToolTipServiceExtended.BindableToolTip="{StaticResource ExampleControlTT}"
Text="Example label:" />
<CheckBox Grid.Row="0"
Grid.Column="1"
x:Name="ExampleControl"
Utilities:ToolTipServiceExtended.BindableToolTip="{StaticResource ExampleControlTT}"
Content="Example" />
Unfortunately, this doesn't make it appear smoothly... When the mouse is moved from the label to the control, or from the control to the label, the tooltip disappears and reopens, appearing to flicker. This occurs even when there is no gap between the label and control, and does not look good. This obviously occurs because they are two separate tooltips.
I would like to somehow group the label and its associated control, and have the tooltip appear on that single group; this way, it can appear fluidly and not flicker when the mouse is moved between the two. Unfortunately, I am struggling to do this. Here are some things I have tried...
Empty TextBlock with the tooltip applied and ColumnSpan=2.
Unfortunately, this prevents the control from receiving mouse clicks, as the TextBlock covers it up invisibly. I have tried setting IsHitTestVisible to false, but then that prevents it from receiving mouse over events, which stops the tooltip appearing at all. If I could just make it so that the mouse clicks through the empty TextBlock, but the TextBlock still gets mouse over events, then it would be perfect.
Code:
<TextBlock Grid.Row="0"
Grid.Column="0"
Text="Example label:" />
<CheckBox Grid.Row="0"
Grid.Column="1"
x:Name="ExampleControl"
Content="Example" />
<TextBlock Grid.Row="0"
Grid.Column="0"
Grid.ColumnSpan="2"
ToolTipService.PlacementTarget="{Binding ElementName=ExampleControl}"
Utilities:ToolTipServiceExtended.BindableToolTip="{StaticResource ExampleControlTT}" />
Nested grid specifically for the one label and one control.
This method seems to work: the tooltip appears whenever the mouse is anywhere over the inner grid, and mouse events are still successfully passed to the control. Unfortunately, this has three problems:
It is very messy, as I will need many nested grids for every label/control combination.
The "Auto" column widths no longer take into account the widths of other controls in the outer grid, because this is of course a separate grid.
It seems to ignore the tooltip placement settings, which are Placement=Right and with PlacementTarget being the specific control. Instead, the tooltip appears underneath the inner grid.
If the last two problems could be fixed, then this would be an acceptable solution.
Code:
<Grid Grid.Row="0"
Grid.Column="0"
Grid.ColumnSpan="2"
ToolTipService.PlacementTarget="{Binding ElementName=ExampleControl}"
Utilities:ToolTipServiceExtended.BindableToolTip="{StaticResource ExampleControlTT}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0"
Grid.Column="0"
Text="Example label:" />
<CheckBox Grid.Row="0"
Grid.Column="1"
x:Name="ExampleControl"
Content="Example" />
</Grid>
Does anybody have any ideas for a good solution to this problem? I simply want my tooltips to appear over both the label and the associated control as though they are one element, without flickering when the mouse is moved between them all. That's all.
Just wrap the controls in a content presenter and attach the tooltip to that.
<Window x:Class="StackOverflowWPF.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<ContentPresenter ToolTip="Blah">
<ContentPresenter.Content>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<TextBlock Text="Example label:"/>
<CheckBox Grid.Column="1" x:Name="ExampleControl" Content="Example" />
</Grid>
</ContentPresenter.Content>
</ContentPresenter>
</Window>
I'm trying to setup a ListBox so that every item has a textblock and a combobox, split evenly across the width of the listbox but I can't seem to find the magic combination of ColumnDefinition properties to do it. Here's my DataTemplate for the listbox item. I've cleaned it up since it was wrong, anyhow.
<DataTemplate x:Key="MyDataTemplate">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" Text="{Binding XPath=text()}"/>
<ComboBox Grid.Column="1" SelectedIndex="0" ItemsSource="{Binding Source={StaticResource Names}, XPath=Name}"></ComboBox>
</Grid>
</DataTemplate>
I've tested a simple application with a grid on a window. Simply specifying two ColumnDefinitions make them automatically take up half of the width, which is nice, but when doing the same in a listboxitem datatemplate, the behavior is different.
How would I change the datatemplate to make it work?
Thanks!
The default HorizontalContentAlignment for a ListBox is Left. You need to set it to Stretch for the ListBoxItems to take up the entire width.
Here's some more info on ListBox/ListBoxItem styles and templates: http://msdn.microsoft.com/en-us/library/cc278062(VS.95).aspx
I have a ListBox with many objects displayed, each of which can be a variable height, based on the number of values each object has. See my previous question that was answered here.
Many objects are 5-lines high, while others are 1. The scroll bar in the ListBox does not appear to like this, probably due to the virtualization. While you scroll through, the thumb on the scroll bar will change its size, based on how many items are actually fitting into the box at that current moment. This makes the thumb very big at times, and very small at other times.
Since this ListBox is also contained within a TabControl, when you switch from one tab to another, the ListBox will often scroll to a different section when you return to it.
Any ideas how to resolve an issue like this?
Additional Info:
Disabling virtualization does fix the scrolling problem, although at the cost of a slower initial display. However, resizing the ListBox with the content inside causes some heavy lag when resizing horizontally (vertical is fine), which I'm assuming is due to my template's width changing and requiring a redraw on every element:
<DataTemplate DataType="{x:Type xmlset:Variable}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="170"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border BorderThickness="1,0,0,1" BorderBrush="Black">
<TextBlock Margin="2,2,0,2" Text="{Binding Path=Identifier.Name, Mode=OneWay}"/>
</Border>
<ItemsControl IsTabStop="False" Grid.Column="1" ItemsSource="{Binding Path=Values, Mode=OneWay}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="120"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border Grid.Column="0" BorderThickness="1,0,0,1" BorderBrush="Black">
<TextBlock Margin="2,2,0,2" Text="{Binding Path=Optimization, Mode=OneWay}"/>
</Border>
<Border Grid.Column="1" Width="Auto" BorderThickness="1,0,1,1" BorderBrush="Black">
<TextBox Margin="0,2,0,2" BorderThickness="0" Text="{Binding Path=Value}" TextChanged="TextBox_TextChanged"/>
</Border>
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>
</DataTemplate>
This is drawing borders around the edges of the fields to make a visual grouping, where val will stretch to the content size. The listbox also has HorizontalContentAlignmment = Stretch to ensure this looks correct.
-------------------
- var - opt - val -
- -------------
- - opt - val -
- -------------
- - opt - val -
-------------------
note: if this needs to be asked in a different question, tell me and i'll seperate the questions
Why not switch off any size restrictions on the ListBox itself, let it size to contents and wrap it into a ScrollViewer, setting a proper size for the latter?
The markup should look like the following:
<ScrollViewer Width="640px" Height="480px">
<ListBox>
<ListBox.ItemTemplate>
<DataTemplate>
<!--Visualization of a list item-->
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</ScrollViewer>
I saw no thumb size changings during scrolling if it was implemented this way.
Set ScrollViewer.CanContentScroll="False" on the ListBox, this will disable what's called "logical scrolling", which does scrolling based on item count instead of height ("physical scrolling").
Disable virtualization or make the items in your ListBox all of equal height. If you've got less than 100 items or so, you can live without the virtualization.