WPF XAML treeview in a stack panel - no scrolling? - wpf

so I have a TreeView control in my XAML. It works fine. If I extend the treeview to be larger than the user control it resides in, I get a scroll bar, which is good. However, inside this user control I want some other things. So I put the treeview in a stack panel with some other things, and this time I don't get the scroll bar if the treeview expands to be larger than the user control it's in.
Is this something other people have come across, and is there a fix for it?

Embed your stackpanel inside a ScrollViewer: stackoverflow.com/a/6250287/7517676. You also might have to explicitly set VerticalScrollBarVisibility and HorizontalScrollBarVisibility, depending on your need.
Here's a code sample:
<ScrollViewer VerticalScrollBarVisibility="Auto">
<StackPanel ... />
</ScrollViewer>

Based on this answer a StackPanel isn't the right container for a TreeView, but a Grid is. So this will enable scrolling inside the TreeView, by mouse and scrollbar:
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="30"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Label>Some descriptive label.</Label>
<TreeView Grid.Row="1" ItemsSource="{Binding SomeSource, Mode=OneWay}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate DataType="{x:Type local:MyNodeType}" ItemsSource="{Binding Children}">
<Label Content="{Binding NodeName}"/>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
</Grid>

Related

How to make scrollviewer work with Height set to Auto in WPF?

I have learned that if the height of a grid row, where the ScrollViewer resides, is set as Auto, the vertical scroll bar will not take effect since the actual size of the ScrollViewer can be larger than the height in sight. So in order to make the scroll bar work, I should set the height to either a fixed number or star height
However, I now have this requirement, that I have two different views reside in two grid rows, and I have a toggle button to switch between these two views: when one view is shown, the other one is hidden/disappeared. So I have defined two rows, both heights are set as Auto. And I bind the visibility of the view in each row to a boolean property from my ViewModel (one is converted from True to Visible and the other from True to Collapsed. The idea is when one view's visibility is Collapsed, the height of the grid row/view will be changed to 0 automatically.
The view show/hidden is working fine. However, in one view I have a ScrollViewer, which as I mentioned doesn't work when the row height is set as Auto. Can anybody tell me how I can fulfill such requirement while still having the ScrollViewer working automatically`? I guess I can set the height in code-behind. But since I am using MVVM, it would require extra communication/notification. Is there a more straightforward way to do that?
In MVVM, the way that worked for me was to bind the height of the ScrollViewer to the ActualHeight of the parent control (which is always of type UIElement).
ActualHeight is a read-only property which is only set after the control has been drawn onto the screen. It may change if the window is resized.
<StackPanel>
<ScrollViewer Height="{Binding Path=ActualHeight,
RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UIElement}}">
<TextBlock Text=Hello"/>
</ScrollViewer>
</StackPanel>
But what if the parent control has an infinite height?
If the parent control has an infinite height, then we have a bigger problem. We have to keep setting the height of all parents, until we hit a control with a non-infinite height.
Snoop is absolutely invaluable for this:
If the "Height" for any XAML element is 0 or NaN, you can set it to something using one of:
Height="{Binding Path=ActualHeight, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UIElement}}"
VerticalAlignment="Stretch"
Height="Auto"
Hint: Use VerticalAlignment="Stretch" if you are a child of a Grid with a <RowDefinition Height="*">, and the Binding RelativeSource... elsewhere if that doesn't work.
If you're interested, here is all of my previous attempts to fix this issue:
Appendix A: Previous Attempt 1
Can also use this:
Height="{Binding Path=ActualHeight, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=StackPanel}}"
Appendix B: Previous Attempt 2
Useful info: see Auto Height in combination with MaxHeight.
If nothing seems to work, it's probably because the ActualHeight of the parent is either 0 (so nothing is visible) or huge (so the scrollviewer never needs to appear). This is more of a problem if there are deeply nested grids, with a scrollviewer right at the bottom.
Use Snoop to find the ActualHeight of the parent StackPanel. In properties, filter by the word "Actual", which brings back ActualHeight and ActualWidth.
If ActualHeight is zero, give it a minimum height using MinHeight, so we can at least see something.
If ActualHeight is so huge that it goes off the edge of the screen (i.e. 16,000), give it a reasonable maximum height using MaxHeight, so the scrollbars will appear.
Once the scrollbars are appearing, then we can clean it up further:
Bind the Height of the StackPanel or Grid to the ActualHeight of the parent.
Finally, put a ScrollViewer inside this StackPanel.
Appendix C: Previous Attempt 3
It turns out that this can sometimes fail:
Height="{Binding Path=ActualHeight, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=StackPanel}}"
The reason? It the binding fails, the height will be zero and nothing will be seen. The binding can fail if we are binding to an element which is not accessible. The binding will fail if we are going up the visual tree, then down to a leaf node (e.g. up to the parent grid, then down to the ActualHeight of a row attached to that grid). This is why binding to the ActualWidth of a RowDefinition simply won't work.
Appendix D: Previous Attempt 4
I ended up getting this working by making sure that Height=Auto for all of the parent elements from us to the first <Grid> element in the UserControl.
Change Height from Auto to *, if you can.
Example:
<Window x:Class="WpfApplication3.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="200" Width="525">
<StackPanel Orientation="Horizontal" Background="LightGray">
<Grid Width="100">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ScrollViewer VerticalScrollBarVisibility="Auto" x:Name="_scroll1">
<Border Height="300" Background="Red" />
</ScrollViewer>
<TextBlock Text="{Binding ElementName=_scroll1, Path=ActualHeight}" Grid.Row="1"/>
</Grid>
<Grid Width="100">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<ScrollViewer VerticalScrollBarVisibility="Auto" x:Name="_scroll2">
<Border Height="300" Background="Green" />
</ScrollViewer>
<TextBlock Text="{Binding ElementName=_scroll2, Path=ActualHeight}" Grid.Row="1"/>
</Grid>
</StackPanel>
</Window>
I've had similar problem, taking me hours to figure out the solution. What solved it was using a Dockpanel as parent container instead of a StackPanel. Just specify all children to dock to top if the functionality should be similar to vertical stackpanel. Consider using LastChildFill="False" in the Dock XAML which is'n default.
So instead of:
<StackPanel Orientation="Horizontal">
<Textbox>SomeTextBox</Textbox>
<Scrollviewer/>
</StackPanel>
Try:
<DockPanel LastChildFill="False">
<Textbox DockPanel.Dock="Top">SomeTextBox</Textbox>
<Scrollviewer DockPanel.Dock="Top"/>
</DockPanel>
You can either set a fix height on your ScrollViewer but then you have to consider that the second row of your grid will have that height too since row's first child will be the ScrollViewer and row's height is auto, or you bind the height of ScrollViewer to another control in your layout. We don't know how your layout looks alike.
At the end if you don't like neither of both just set the row's height to * as swiszcz suggested or hack wpf write your own custom panel that will be able to layout everything possible in every parallel universe or something like that. :)
What I discover is that you have to put your ScrollViewer within a container that has Height=Auto or you get his parent Heigh Actual Size and apply it to that container.
In my case I have UserControl like
<Grid Margin="0,0,0,0" Padding="0,2,0,0">
<ScrollViewer Height="Auto" ZoomMode="Disabled" IsVerticalScrollChainingEnabled="True" VerticalAlignment="Top"
HorizontalScrollMode="Enabled" HorizontalScrollBarVisibility="Disabled"
VerticalScrollMode="Enabled" VerticalScrollBarVisibility="Visible">
<ListView ItemsSource="{x:Bind PersonalDB.View, Mode=OneWay}" x:Name="DeviceList"
ScrollViewer.VerticalScrollBarVisibility="Hidden"
ItemTemplate="{StaticResource ContactListViewTemplate}"
SelectionMode="Single"
ShowsScrollingPlaceholders="False"
Grid.Row="1"
Grid.ColumnSpan="2"
VerticalAlignment="Stretch"
BorderThickness="0,0,0,0"
BorderBrush="DimGray">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<ItemsStackPanel AreStickyGroupHeadersEnabled="False" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate x:DataType="local1:GroupInfoList">
<TextBlock Text="{x:Bind Key}"
Style="{ThemeResource TitleTextBlockStyle}"/>
</DataTemplate>
</GroupStyle.HeaderTemplate>
</GroupStyle>
</ListView.GroupStyle>
</ListView>
</ScrollViewer>
</Grid>
And I add it dinamically to ContentControl which is within a Page.
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" Margin="0,0,12,0">
<Grid.RowDefinitions>
<RowDefinition Height="70" />
<RowDefinition Height="*" MinHeight="200" />
</Grid.RowDefinitions>
<Grid Grid.Row="1" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" >
<ContentControl x:Name="UIControlContainer" />
</Grid>
</Grid>
Notice that Heigh of the Row is *
When I populate ContentControl I use this code in Loaded event
UIControlContainer.Content = new UIDeviceSelection() {
VerticalAlignment = VerticalAlignment.Stretch,
HorizontalAlignment = HorizontalAlignment.Stretch,
Height = UIControlContainer.ActualHeight,
Width = UIControlContainer.ActualWidth
};
And also when ContentControl changes its size you have to update size of the UserControl.
UIControlContainer.SizeChanged += UIControlContainer_SizeChanged;
private void UIControlContainer_SizeChanged(object sender, SizeChangedEventArgs e)
{
if (UIControlContainer.Content != null)
{
if (UIControlContainer.Content is UserControl)
{
(UIControlContainer.Content as UserControl).Height = UIControlContainer.ActualHeight;
(UIControlContainer.Content as UserControl).Width = UIControlContainer.ActualWidth;
}
}
}
Enjoy!
P.S. Acctually I did it for UWP.

DevExpress LayoutSplitter and DockLayoutManager drag and drop issue

I am having some some problems using the LayoutSplitter and DockLayoutManger from DevExpress.
dxdo:DockLayoutManager>
<dxdo:DockLayoutManager.LayoutRoot>
<dxdo:LayoutGroup Orientation="Vertical" Height="*">
<dxdo:LayoutGroup Orientation="Vertical" Height="*">
<dxdo:DocumentPanel>
<Grid VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
<Grid.RowDefinitions>
<RowDefinition Height="*"></RowDefinition>
</Grid.RowDefinitions>
<ContentControl Grid.Row="0" Content="{Binding SomeViewModel}" ContentTemplateSelector="{StaticResource templateSelector}"/>
</Grid>
</dxdo:DocumentPanel>
</dxdo:LayoutGroup>
<dxdo:LayoutGroup Height="Auto" Orientation="Vertical">
<dxdo:LayoutSplitter/>
</dxdo:LayoutGroup>
<dxdo:LayoutGroup>
<dxdo:LayoutPanel Height="Auto" AllowDock="True">
<ItemsControl ItemsSource="{Binding SomeViewModel.SomeCollection}" ItemTemplateSelector="{StaticResource templateSelector}">
</ItemsControl>
</dxdo:LayoutPanel>
</dxdo:LayoutGroup>
</dxdo:LayoutGroup>
</dxdo:DockLayoutManager.LayoutRoot>
</dxdo:DockLayoutManager>
The LayoutSplitter isn't moving up and down. It just remains static.
With the DockLayoutManager, the 3rd nested LayoutGroup, when I remove a component from it, I can't drop the component back in. A hint would be great thanks!
The LayoutSplitter control is needed to split layout groups or layout control items. It can't be used with LayoutPanels or DocumentPanels. Moreover it is not needed to use splitters with dock items because these items resizing are automatically provided by the DockLayoutManager. You should also use the DocumentPanel as child item for the DocumentGroup instead of placing that document directly to the LayoutGroup.Items collection. Or use the LayoutPanel instead of the DocumentPanel.
So, you markup should looks like this:
<dxdo:DockLayoutManager>
<dxdo:LayoutGroup Orientation="Vertical" >
<dxdo:DocumentGroup>
<dxdo:DocumentPanel Caption="Document">
<!-- Document content -->
</dxdo:DocumentPanel>
</dxdo:DocumentGroup>
<dxdo:LayoutGroup>
<dxdo:LayoutPanel Caption="Panel">
<!-- Panel content -->
</dxdo:LayoutPanel>
</dxdo:LayoutGroup>
</dxdo:LayoutGroup>
</dxdo:DockLayoutManager>
You can read more in these articles:
Dock Layout Manager Fundamentals
Layout Groups
Dock Items
Layout Items
Document Groups and Panels

TabControl width increases on adding tabs

My application UI is divided in 2 parts. Left side is Navigation Menu and Right is View Area where the selected Menu content is displayed. Now, one of the menu is reports. I am using Tabcontrol with Header and Content Template. Template has a ViewModel as DataType and content as the respective View which is a UserControl. This TabControl is inside a scrollviewer which is set as horizontal and vertical alignment to stretch.
The user control hosts a ContentPresenter inside a Grid which is bound to a ReportHost which has a reportviewer as child. I am using this ReportViewer to generate reports.
When the user opens a report, it opens in a new tab. It works fine till the number of tabs is such that the tabheaders are contained inside the viewing area. But as soon as more tabs are added, it causes the tabcontrol width to stretch, causing the content area of the tab to stretch and the contentpresenter also stretches causing horizontal scroll to appear.
This finally result in the report to stretch and due to some reason, unknown to me, the report overlaps the Navigation Area of the UI, as if it is not a part of the UI but is overlapping it. The whole report keeps on floating on top of the View Area and Navigation menu on scrolling.
I can fix it by providing the MaxWidth to the ScrollViewer but I don't want to do that. I would like the width of the tabcontroll or the Scrolviewer to be decided purely based on available View Area. How do I do this through the code or XAML without using fixed width.
I am not sure if I was able to explain the situation. Please let me know if more information or clarification is needed. I would be more than happy to provide details.
Edit: Adding Code for information.
<DataTemplate x:Key="TabContent" DataType="{x:Type VM:ReportViewModel}">
<View:Report/>
</DataTemplate>
<DataTemplate x:Key="TabHeader" DataType="{x:Type VM:ReportViewModel}">
<ContentPresenter Content="{Binding Path=TabHeader}"
VerticalAlignment="Center"/>
</DataTemplate>
<ScrollViewer HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
<Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock HorizontalAlignment="Left" TextWrapping="Wrap"
Text="Reports" VerticalAlignment="Top" Margin="10,13,0,0"
FontSize="18.667" FontFamily="Segoe UI" Foreground="White"/>
<Border BorderThickness="0" Margin="0,50,0,0"
Background="{DynamicResource Brush_HeaderNew}" Height="50" Width="Auto"
VerticalAlignment="Top"/>
<TabControl ItemsSource="{Binding ReportItems}" Grid.Row="1" Margin="0,20,0,0"
SelectedItem="{Binding SelectedReportItem}"
ContentTemplate="{StaticResource TabContent}"
ItemTemplate="{StaticResource TabHeader}"
/>
</Grid>
</ScrollViewer>
ScrollViewer presents to its child an infinitely large area on which to set itself out, because it reasons that it can just offer scrolling if it's bigger than the space available to ScrollViewer itself. Because yours has scrolling enabled in both directions, that means the TabControl can expand as much as it likes in either direction, and it's not going to be smart enough to know that it's inside a ScrollViewer and that you want the tabs to not take advantage of this virtual space.
From the sound of things, you might want to consider moving the ScrollViewer within the TabControl so that only the contents of the tab is scrollable rather than the whole set. You should be able to do that by modifying the tab content template.

WPF TextBox Wrapping

I am trying to figure out how to get a textbox to wrap its contents, however the situation isn't quite the same as the typical "it doesn't wrap" scenario. My textbox is contained inside a DataTemplate which is used inside a Telerik RadTabControl instance (using a ContentTemplatePresenter to determine which view to display) and the XAML for the DataTemplate looks like this:
<DataTemplate x:Key="NotesTemplate">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<TextBlock Text="Use the box below to record any general notes associated with this item." Style="{StaticResource Default}" />
<TextBox TextWrapping="Wrap" AcceptsReturn="True" VerticalScrollBarVisibility="Auto" GridRow="1" Margin="20" Text="{Binding Notes, UpdateSourceTrigger=PropertyChanged}" />
</Grid>
</DataTemplate>
The reason I say it doesn't fall under the normal "it doesn't wrap" scenario is it used to wrap until I had to change the view to be resizable to anything to support the varying screen sizes the app will be run on. When I did that the TextBox stopped wrapping because (presumably) as the user types something the TextBox says "I need more space" so the parent obliges and the box continues out to the right indefinitely (although the view gets scrollbars). I tried setting a MaxWidth using Binding/RelativeSource, but since the parent is specifically designed to grow that approach won't work. What I need to have happen is the box should be the width of its' containing parents' VisibleWidth. Meaning, if the Window itself is 1024x768, the TextBox's MaxWidth should be 1024 and any text thereafter would automatically wrap, but if the Window grows to 1280x1024 the box should now be 1280 and the text wrap accordingly. I tried this scenario with this binding expression, but no luck:
MaxWidth="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}, Path=ActualWidth}"
The Window size itself isn't growing so if I could get the Window's Width (minus a certain amount to cover the width of the tabs that are part of the TabControl) I believe that would work.
Any ideas?
although the view gets scrollbars
Disable the horizontal scrollView, so it will be forced to wrap. You can try to disable it on the TextBox itself, or on the wrapping Grid.
<DataTemplate x:Key="NotesTemplate">
<Grid ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<TextBlock Text="Use the box below to record any general notes associated with this item." Style="{StaticResource Default}" />
<TextBox TextWrapping="Wrap" AcceptsReturn="True" VerticalScrollBarVisibility="Auto" Grid.Row="1" Margin="20" Text="{Binding Notes, UpdateSourceTrigger=PropertyChanged}" />
</Grid>
</DataTemplate>

wpf layout help

I have the following xaml which resides in a wpf user control -
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="30" />
<RowDefinition Height="*" />
<RowDefinition Height="30" />
</Grid.RowDefinitions>
<TextBox
x:Name="MyTxt"
TextWrapping="WrapWithOverflow"
Grid.Row="0"
/>
<ListView
x:Name="MyList"
ItemsSource="{Binding}"
Grid.Row="1"
/>
<Label
Grid.Row="2"
/>
</Grid>
This control is nested within a grid in a view. I would like to have the text box be a set height at the top of the grid, the label at the bottom showing as a fixed height at the bottom of the grid. I want the list view to fill the rest of the screen area.
The problem that I am having is the listview does not size correctly. If I have too many records that show up in it, it extends beyond the window and no scroll bars are available to scroll down. I therefore cannot get to the bottom to see the vertical scroll bar if the data stretches off to the right of the screen.
I was able to set the listview to a fixed height and that worked, but I would like it to be more dynamic and resize with the window if possible.
Does anyone have any tips that might get the sizing correct?
Thanks for any thoughts.
EDIT - Here is the xaml for the containing grid in the mainwindow view. this was adapted from the article by Josh Smith here
<Grid>
<Border
Style="{StaticResource MainBorderStyle}"
>
<HeaderedContentControl
Content="{Binding Path=Workspaces}"
ContentTemplate="{StaticResource WorkspacesTemplate}"
/>
</Border>
</Grid>
I do have the scrollviewer properties set as mentioned in some of the answers below.
Here is the datatemplate for the workspace
<DataTemplate x:Key="WorkspacesTemplate">
<TabControl
IsSynchronizedWithCurrentItem="True"
ItemsSource="{Binding}"
ItemTemplate="{StaticResource ClosableTabItemTemplate}"
Margin="4"
/>
</DataTemplate>
Can you just add these properties to the listview?
ScrollViewer.CanContentScroll = "True"
ScrollViewer.VerticalScrollBarVisibility="Visible" <!-- or "Auto" -->
Everything else looks ok to me. You have the 3 rows, 2 of which are absolute, the other stretching. You also have the listview in the 2nd row, so it should stretch with it.
if that doesn't work, try wrapping the ListView in a scrollviewer
<ScrollViewer>
<ListView/>
</ScrollViewer>
What is the VerticalAlignment of a ListBox by default? You might need to set the vertical alignment to Stretch.
<ListView
x:Name="MyList"
ItemsSource="{Binding}"
Grid.Row="1"
VerticalAlignment="Stretch"
/>
I was able to get it working. If I change the containing grid in the main window to use a ContentControl instead of a HeaderedcontentControl, it works as expected.
Thank for any help.

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