I have a ListBox displaying some items, and in certain modes I "stamp" a kind of watermark across the top of it. I've done this with a Border containing a TextBlock with an Opacity of 0.5. All this works nicely.
However, I still want the user to be able to click on the items in the ListBox but if I click on the "stamp" it obviously eats the click events and they're not seen by the ListBox.
What do I have to do to prevent this? (i.e. allow the ListBox to see the Click event)
Thanks,
Craig
You can do this with the IsHitTestVisible property:
<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ListBox>
<ListBoxItem>a</ListBoxItem>
<ListBoxItem>b</ListBoxItem>
<ListBoxItem>c</ListBoxItem>
</ListBox>
<Border Opacity="0.2" Background="Cyan" BorderBrush="Black" BorderThickness="5" IsHitTestVisible="False" >
<TextBlock Text="EXAMPLE" FontSize="20" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
</Grid>
Related
Apparently, setting a UniformGrid's Background property affects the control's boundaries. See the following example:
<StackPanel>
<UniformGrid Rows="0" Columns="0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Height="32" Background="Aqua" PreviewMouseUp="UIElement_OnPreviewMouseUp">
<!--Clicking on this UniformGrid fires the event-->
</UniformGrid>
<Border BorderBrush="Black" BorderThickness="1"></Border>
<UniformGrid Rows="0" Columns="0" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Height="32" PreviewMouseUp="UIElement_OnPreviewMouseUp">
<!--Clicking on this UniformGrid DOESN'T fire the event-->
</UniformGrid>
<Border BorderBrush="Black" BorderThickness="1"></Border>
</StackPanel>
Both UniformGrids take up space of the same size when rendered. However, clicking inside the second UniformGrid's area doesn't raise the PreviewMouseUp event. The only difference between the two controls is the Background property.
Why does the Background property affect the region where clicks (and presumably other input events) are registered?
Edit:
If I declare the Background to be Transparent, the event is raised properly. The interaction is ignored only when there's no Background declaration at all.
Hi I want to click through my listBox (click on empty space) and want the click on the underlying border control. I'm really sure that I have done this in the past using {x:Null} as the Background for a control. But this time it doesn't work.
Any hint why?
<Grid>
<Border x:Name="BrushBorder" Background="{Binding ActualBrush}" Margin="7,0" Height="10"
VerticalAlignment="Top" Cursor="Pen">
<dxmvvm:Interaction.Behaviors>
<dxmvvm:EventToCommand EventName="MouseDown" Command="{Binding NewGradientStopCommand}" PassEventArgsToCommand="True" />
</dxmvvm:Interaction.Behaviors>
</Border>
<ListBox x:Name="GradientStopListBox" ItemsSource="{Binding GradientStops}" SelectedItem="{Binding ActualGradientStop}"
HorizontalContentAlignment="Stretch"
VerticalContentAlignment="Stretch"
Background="{x:Null}" BorderBrush="{x:Null}">
I found the answer. The ListBox includes a ScrollViewer and this is causing the mouse click the stay in the ListBox regradless of the BackgroundBrush.
See this question for further information:
Transparent WPF ListBox with selectable items
How can I create the effect similar to Windows Phone's MessageBox, where the message gets displayed on a new layer with transparent background, so that the windows becomes modal? My layout is created out of Grid, so I do not know how to add any content over it. Please help.
It's easy to overlay one set of content with another in WPF. Try changing the visibility of the border below, for a simple message box effect. You would of course bind Visibility to your view model, or set it in code behind.
<Grid>
<Grid>
<!-- All your layout here -->
</Grid>
<Border Height="100" Width="100" Background="Azure" Visibility="Hidden">
<TextBlock Text="Hi there" HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
</Grid>
I have an ItemsControl in my user control with a scroll viewer around it for when it gets too big (Too big being content is larger than the viewable area of the UserControl). The problem is that the grid that it is all in just keeps expanding so that the scroll viewer never kicks in (unless I specify an exact height for the grid). See code below and thanks in advance.
<UserControl x:Class="BusinessObjectCreationWizard.View.TableSelectionPageView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<GroupBox FontWeight="Bold" Height="300px"
Header="Tables"
Padding="2">
<ScrollViewer>
<ItemsControl FontWeight="Normal"
ItemsSource="{Binding Path=AvailableTables}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<CheckBox Content="{Binding Path=DisplayName}"
IsChecked="{Binding Path=IsSelected}"
Margin="2,3.5" />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</ScrollViewer>
</GroupBox>
</UserControl>
This user control is loaded here
<Border Background="White" Grid.Column="1" Grid.Row="0">
<HeaderedContentControl Content="{Binding Path=CurrentPage}"
Header="{Binding Path=CurrentPage.DisplayName}" />
</Border>
I would like to not specify the height.
If you remove the Height from your GroupBox (which, as far as I understand, is what you want to do), then it will fill its container, unless there's a panel upstream that imposes its own sizing rules.
I used this simplified version of your XAML. I removed the template and the binding, and hard-coded some items, to make this stand alone; those changes won't affect the way layout is done.
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
<GroupBox FontWeight="Bold" Header="Tables" Padding="2">
<ScrollViewer>
<ItemsControl FontWeight="Normal">
<TextBlock>Foo</TextBlock>
<TextBlock>Bar</TextBlock>
<TextBlock>Baz</TextBlock>
</ItemsControl>
</ScrollViewer>
</GroupBox>
</Window>
Run it, and you'll see that the content does indeed size to fit the window, and the scrollbar only enables when the window gets too small to see all three items. I believe this is what you want.
So the problem is most likely one of the parent panels, one you're not showing in your sample XAML. The problem you describe could occur if your GroupBox appears inside a StackPanel:
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
<StackPanel>
<GroupBox FontWeight="Bold" Header="Tables" Padding="2">
<ScrollViewer>
<ItemsControl FontWeight="Normal">
<TextBlock>Foo</TextBlock>
<TextBlock>Bar</TextBlock>
<TextBlock>Baz</TextBlock>
</ItemsControl>
</ScrollViewer>
</GroupBox>
</StackPanel>
</Window>
Now the GroupBox appears at the top of the Window, sized to exactly fit its contents. If you shrink the Window enough, the GroupBox will be cut off -- because it's sized to fit its content, not its container. This sounds like the problem you're describing.
The reason is that StackPanel asks its children what their ideal height is (based on their content), and uses that height. Without StackPanel (or something similar), the default is to respect the control's VerticalAlignment, and if that's set to the default value of Stretch, then the control is stretched to fill its parent. This means it won't be taller than its parent, which sounds like what you want.
Solution: remove the StackPanel (or whatever else is causing you problems) and use something else. Depending on what you're trying to accomplish, you might have better luck with a DockPanel or a Grid. Hard to tell without knowing more about your layout.
Edit: Okay, it looks like the problem is indeed the HeaderedContentControl parent -- but not directly. HeaderedContentControl isn't a panel, so it doesn't do any layout of its own (and its descendant, GroupBox, doesn't have this same problem). The problem is its default template -- which includes a StackPanel. The good news is, you're free to use a different template, let's say one with a DockPanel instead:
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<HeaderedContentControl>
<HeaderedContentControl.Style>
<Style TargetType="{x:Type HeaderedContentControl}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type HeaderedContentControl}">
<DockPanel>
<ContentPresenter ContentSource="Header" DockPanel.Dock="Top"/>
<ContentPresenter/>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</HeaderedContentControl.Style>
<GroupBox FontWeight="Bold" Header="Tables" Padding="2">
<ScrollViewer>
<ItemsControl FontWeight="Normal">
<TextBlock>Foo</TextBlock>
<TextBlock>Bar</TextBlock>
<TextBlock>Baz</TextBlock>
</ItemsControl>
</ScrollViewer>
</GroupBox>
</HeaderedContentControl>
</Window>
If you leave off the <HeaderedContentControl.Style> part, this reproduces your problem; but with the style in place, it allows the GroupBox to fill its container, so the ScrollViewer will get a scrollbar when you want it to.
If the previous answer doesn't fix the problem, you could also try binding the Width, Height of your grid to the ActualWidth, ActualHeight of your parent UserControl. Something like:
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="WpfApplication.UserControl1"
x:Name="UserControl">
<Grid Height="{Binding ElementName=UserControl, Path=ActualHeight}"
Width="{Binding ElementName=UserControl, Path=ActualWidth}" />
In this case you aren't setting an explicit width and height but you are limiting the Grids width/height to the constraints of the UserControl it sits in.
I had the same issue, after reading this response I replaced all StackPanels with Grids in UserControl. It resolved the Scrollbar issue.
Try removing the grid entirely and setting the HorizontalAlignment and VerticalAlignment directly on the GroupBox. If a layoutpanel has only one child, it's often redundant... this migth be true in your case.
If that doesn't work... what's the parent of your grid control?
Why not just use a listbox instead of an itemscontrol, that has a built in scrollviewer.
They are different. If you do not want to have the items selectable, then don't use a ListBox. It is going to be heavier, and will also have the deselect a selection everytime the user clicks on an entry. Just put the ItemsControl in a ScrollViewer
I had the same problema with ListBox, it wasn't expanding and the scroll viewer didn't appear. I solved it as follows:
<UserControl x:Class="TesteView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Grid MaxHeight="710">
....
....
<StackPanel>
<ListBox MaxHeight="515"
ScrollViewer.HorizontalScrollBarVisibility="Hidden"
ScrollViewer.VerticalScrollBarVisibility="Auto"
ItemsSource="{Binding Path=Teste,Mode=TwoWay}">
....
....
</ListBox>
</StackPanel>
</Grid>
</UserControl>
What is difference between a ControlTemplate and a DataTemplate in WPF?
Typically a control is rendered for its own sake, and doesn't reflect underlying data. For example, a Button wouldn't be bound to a business object - it's there purely so it can be clicked on. A ContentControl or ListBox, however, generally appear so that they can present data for the user.
A DataTemplate, therefore, is used to provide visual structure for underlying data, while a ControlTemplate has nothing to do with underlying data and simply provides visual layout for the control itself.
A ControlTemplate will generally only contain TemplateBinding expressions, binding back to the properties on the control itself, while a DataTemplate will contain standard Binding expressions, binding to the properties of its DataContext (the business/domain object or view model).
Very basically a ControlTemplate describes how to display a Control while a DataTemplate describes how to display Data.
For example:
A Label is a control and will include a ControlTemplate which says the Label should be displayed using a Border around some Content (a DataTemplate or another Control).
A Customer class is Data and will be displayed using a DataTemplate which could say to display the Customer type as a StackPanel containing two TextBlocks one showing the Name and the other displaying the phone number. It might be helpful to note that all classes are displayed using DataTemplates, you will just usually use the default template which is a TextBlock with the Text property set to the result of the Object's ToString method.
Troels Larsen has a good explanation on MSDN forum
<Window x:Class="WpfApplication7.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">
<Window.Resources>
<DataTemplate x:Key="ButtonContentTemplate">
<StackPanel Orientation="Horizontal">
<Grid Height="8" Width="8">
<Path HorizontalAlignment="Stretch"
Margin="0,0,1.8,1.8"
VerticalAlignment="Stretch" Stretch="Fill" Stroke="#FF000000"
Data="M0.5,5.7 L0.5,0.5 L5.7,0.5"/>
<Path HorizontalAlignment="Stretch"
Margin="2,3,0,0"
VerticalAlignment="Stretch" Stretch="Fill" Stroke="#FFFFFFFF"
Data="M3.2,7.5 L7.5,7.5 L7.5,3.5"/>
<Path HorizontalAlignment="Stretch"
Margin="1.2,1.4,0.7,0.7"
VerticalAlignment="Stretch" Fill="#FFFFFFFF" Stretch="Fill" Stroke="#FF000000"
Data="M2.5,2.5 L7.5,7.5"/>
<Path HorizontalAlignment="Stretch"
Margin="1.7,2.0,1,1"
VerticalAlignment="Stretch" Stretch="Fill" Stroke="#FF000000"
Data="M3,7.5 L7.5,7.5 L7.5,3.5"/>
<Path HorizontalAlignment="Stretch"
Margin="1,1,1,1"
VerticalAlignment="Stretch" Stretch="Fill" Stroke="#FFFFFFFF"
Data="M1.5,6.5 L1.5,1 L6.5,1.5"/>
</Grid>
<ContentPresenter Content="{Binding}"/>
</StackPanel>
</DataTemplate>
<ControlTemplate TargetType="Button" x:Key="ButtonControlTemplate">
<Grid>
<Ellipse Fill="{TemplateBinding Background}"/>
<ContentPresenter HorizontalAlignment="Center"
VerticalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Window.Resources>
<StackPanel>
<Button Template="{StaticResource ButtonControlTemplate}" ContentTemplate="{StaticResource ButtonContentTemplate}" Content="1"/>
<Button Template="{StaticResource ButtonControlTemplate}" ContentTemplate="{StaticResource ButtonContentTemplate}" Content="2"/>
<Button Template="{StaticResource ButtonControlTemplate}" ContentTemplate="{StaticResource ButtonContentTemplate}" Content="3"/>
</StackPanel>
</Window>
(Templates blatently stolen from
http://msdn.microsoft.com/en-us/library/system.windows.controls.controltemplate.aspx
and
http://msdn.microsoft.com/en-us/library/system.windows.controls.contentcontrol.contenttemplate%28VS.95%29.aspx
respectively)
Anyway, the ControlTemplate decides how the Button itself looks, while
the ContentTemplate decides how the Content of the button looks. So
you could bind the content to one of you data classes and have it
present itself however you wanted it.
ControlTemplate: Represents control style.
DataTemplate: Represents data style(How would you like to show your data).
All controls are using default control template that you can override through template property.
For example
Button template is a control template.
Button content template is a data template
<Button VerticalAlignment="Top" >
<Button.Template>
<ControlTemplate >
<Grid>
<Rectangle Fill="Blue" RadiusX="20" RadiusY="20"/>
<Ellipse Fill="Red" />
<ContentPresenter Content="{Binding}">
<ContentPresenter.ContentTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Height="50">
<TextBlock Text="Name" Margin="5"/>
<TextBox Text="{Binding UserName, Mode=TwoWay}" Margin="5" Width="100"/>
<Button Content="Show Name" Click="OnClickShowName" />
</StackPanel>
</DataTemplate>
</ContentPresenter.ContentTemplate>
</ContentPresenter>
</Grid>
</ControlTemplate>
</Button.Template>
</Button>
public String UserName
{
get { return userName; }
set
{
userName = value;
this.NotifyPropertyChanged("UserName");
}
}
ControlTemplate - Changing the appearance of element. For example Button can contain image and text
DataTemplate - Representing the underlying data using the elements.
ControlTemplate DEFINES the visual appearance, DataTemplate REPLACES the visual appearance of a data item.
Example: I want to show a button from rectangular to circle form => Control Template.
And if you have complex objects to the control, it just calls and shows ToString(), with DataTemplate you can get various members and display and change their values of the data object.
All of the above answers are great but there is a key difference that was missed. That helps make better decisions about when to use what. It is ItemTemplate property:
DataTemplate is used for elements that provide ItemTemplate property for you to replace its items' content using DataTemplates you define previously according to bound data through a selector that you provide.
But if your control does not provide this luxury for you then you still can use a ContentView that can display its content from predefined ControlTemplate. Interestingly, you can change the ControlTemplate property of your ContentView at runtime. One more thing to note that unlike controls with ItemTemplate property, you cannot have a TemplateSelector for this (ContentView) control. However, you still can create triggers to change the ControlTemplate at runtime.