I have a LongListSelector where each item can contain variable number of images and hence can be of different height. Here's my XAML:
<phone:LongListSelector x:Name="Views" ItemsSource="{Binding}">
<phone:LongListSelector.ItemTemplate>
<DataTemplate>
<ItemsControl ItemsSource="{Binding Imgs}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Border Background="#44AAAAAA" Margin="10,0,10,10">
<Image Source="{Binding photo.Source}" Stretch="UniformToFill"
Height="{Binding Converter={StaticResource ScaleHeight}, Path=photo}" />
</Border>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</DataTemplate>
</phone:LongListSelector.ItemTemplate>
</phone:LongListSelector>
The problem is while scrolling such LongListSelector when I come across a long item, the scroll position suddenly jumps a few items forward/backward (depending of scroll direction).
I suspect this has something to do with virtualization but I don't know how this can be fixed. Any suggestions?
You should use the Grouped version of the LongListSelector with an empty header, like this you will not have items with such different Height.
Related
Got a GridView that its items width are set by the first one width(Screenshot)
How could I set some auto width for each item?
<GridView ItemsSource="{x:Bind PopularItems}" Style="{StaticResource GVStyle}" Height="230">
<GridView.ItemTemplate>
<DataTemplate x:Name="GVTemp" x:DataType="models:LessDetails">
<StackPanel>
<Image Height="180" Width="132" Source="{x:Bind Img}" />
<TextBlock Margin="4,4,0,4" HorizontalAlignment="Stretch" TextAlignment="Center"
Text="{x:Bind Name}" Style="{ThemeResource BodyTextBlockStyle}" />
</StackPanel>
</DataTemplate>
</GridView.ItemTemplate>
You can not auto-width each item in a GridView control, it is by designed to use the first item's size as the uniform size (ListViewItemPresenter for each items has the same size).
For the auto-size scenario, I suggest you using the StackPanel or creating a custom ItemsControl.
Use an ItemsStackPanel:
<GridView.ItemsPanel>
<ItemsPanelTemplate>
<ItemsStackPanel Orientation="Horizontal" VerticalAlignment="Top" HorizontalAlignment="Left" />
</ItemsPanelTemplate>
</GridView.ItemsPanel>
The only downside is that it doesn't wrap items.. For that you can use the ItemsWrapGrid but then you lose the auto-width functionality (first item determines the width of all items).
There's also the VariableSizedWrapGrid that can be used by giving items a certain ColumnSpan/RowSpan, but it's not quite the same as automatically calculating the width.
If you want the best of both world, probably you'll need to write your own custom panel.
UPDATE: For a solution that allows for both automatic width and item wrapping, you can use the WrapPanel control from the UWP Community Toolkit.
I have created info inside a PivotItem but for some reason the items do not scroll, I've tried scrolling but it creates a sort of compressed effect and not scrolling down.
I have tried wrapping it with a ScrollViewer and also tried
<ItemsControl.Template>
<ControlTemplate>
<ScrollViewer VerticalScrollBarVisibility="Visible" VerticalScrollMode="Enabled">
<ItemsPresenter />
</ScrollViewer>
</ControlTemplate>
</ItemsControl.Template>
With no luck - can anyone identify what could be wrong?
<PivotItem Header="unread">
<ItemsControl ItemsSource="{Binding Categories}" >
<ItemsControl.Template>
<ControlTemplate>
<ScrollViewer VerticalScrollBarVisibility="Visible" VerticalScrollMode="Enabled" BringIntoViewOnFocusChange="True">
<ItemsPresenter />
</ScrollViewer>
</ControlTemplate>
</ItemsControl.Template>
<ItemsControl.ItemTemplate>
<DataTemplate>
// ---
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</PivotItem>
Just put the ScrollViewer around the ItemsControl, not inside it. Something like this:
<Pivot TabNavigation="Once">
<PivotItem Header="unread">
<ScrollViewer>
<ItemsControl ItemsSource="{Binding Categories}">
//Some ItemsControl properties and stuff
</ItemsControl>
</ScrollViewer>
</PivotItem>
</Pivot>
Solved
For everyone reading this - the problem was that the Pivot was in a StackPanel. And ScrollViewers do not work inside of StackPanels, because these panels have unlimited height (or width, depending on the Orientation), and then there's nothing to scroll as everything fits. You could use a StackPanel inside a ScrollViewer, though.
I have the following ListView defined in a Grid win a <RowDefinition Height="8"> to take up all the visible area. The Listview is bound and created and populated on the fly at page creation. Essentially the list is going to be bigger than the viewable area and taller than the viewable area, so I want to be able to scroll up to down and left to right.
Basically, the vertical scroll bar appears but it doesn't work. It shows lots of area to be scrolled but it is unmoveable with mouse. The Horizontal scroll seems to appear off the bottom of the list as the mouse wheel does scroll horizontally, but the scroll bar isn't seen.
<ListView
x:Name="itemListViewHorizontal"
AutomationProperties.AutomationId="ItemListView"
AutomationProperties.Name="Grouped Items"
Grid.Row="1"
Visibility="Visible"
Margin="0,-10,0,0"
Padding="10,0,0,60"
ItemsSource="{Binding Source={StaticResource SearchItemsViewSource}}"
ItemTemplate="{StaticResource Standard80PersonTemplate}"
SelectionMode="None"
IsSwipeEnabled="false"
IsItemClickEnabled="True"
ItemClick="ItemView_ItemClick">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel Orientation="Horizontal"/>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.GroupStyle>
<GroupStyle>
<GroupStyle.HeaderTemplate>
<DataTemplate>
<Grid Margin="7,7,0,0">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Title}" Margin="3,-7,10,10" Style="{StaticResource GroupHeaderTextStyle}" />
<TextBlock Text="{StaticResource ChevronGlyph}" FontFamily="Segoe UI Symbol" Margin="0,-7,0,10" Style="{StaticResource GroupHeaderTextStyle}"/>
</StackPanel>
</Grid>
</DataTemplate>
</GroupStyle.HeaderTemplate>
<GroupStyle.Panel>
<ItemsPanelTemplate>
<VariableSizedWrapGrid Orientation="Vertical" Margin="0,0,80,0"/>
</ItemsPanelTemplate>
</GroupStyle.Panel>
</GroupStyle>
</ListView.GroupStyle>
</ListView>
Essentially, what I want is to have the scrollbars at the left and bottom to scroll side to side or top to bottom. But no matter what I try, short of getting rid of the ItemsPanelTemplate and ItemsPanel information, which makes a single long list, it doesn't work.
Any suggestions?
In changing this, my vertical scrollbar works but horizontal is toast.
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal" ScrollViewer.HorizontalScrollBarVisibility="Visible" ScrollViewer.VerticalScrollBarVisibility="Visible"/>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
Well, I was looking for a much more elegant way of doing this. Apparently, stackpanel cannot be used for both scrollbars at the same time, though it doesn't explicitly say this. So, I surrounded my listview with a scrollviewer, using a name and then disabling on snap view.
Problems solved, but I was looking for a way without so much nesting, but, it is what it is.
I'm relatively new to XAML and Windows Phone development.
I have a ListBox that display a text block. Everything works fine when I just have the ListBox inside a grid, including the scrolling. I wanted the user to be able to collapse the ListBox if they wanted more space on the page to look at other elements, so I surrounded the ListBox with an ExpanderView. Once I did that though, the ListBox won't scroll down anymore. If I try to scroll down, it acts as if I am trying to scroll up and "squishes" the text vertically. If I try to scroll up, it also "squishes" the text vertically, but that is the expected behavior for scrolling up.
Here is the relevant part of my XAML code:
<toolkit:ExpanderView Header="Chatlog" x:Name="chatlogExpander" FontSize="24" VerticalAlignment="Top" Grid.Row="2">
<toolkit:ExpanderView.Items>
<ListBox ItemsSource="{Binding chatlog}" ScrollViewer.VerticalScrollBarVisibility="Auto" Grid.Row="2">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Vertical"/>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock x:Name="ChatBlock" TextWrapping="Wrap">
<Run Text="{Binding player}" Foreground="{Binding color}" FontSize="24" FontWeight="Bold"/><Run Text="{Binding text}" Foreground="{Binding color}" FontSize="24"/>
</TextBlock>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</toolkit:ExpanderView.Items>
</toolkit:ExpanderView>
I appreciate any help you guys can give me!
I tried an example with your code and after specifying a Height for the ListBox, it started to scroll fine.
In the following XAML, the word "Test" centers horizontally but not vertically.
How can I get it to center vertically?
<Window x:Class="TestVerticalAlign2343.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
WindowStartupLocation="CenterScreen"
Title="Window1" Height="768" Width="1024">
<DockPanel LastChildFill="True">
<Slider x:Name="TheSlider"
DockPanel.Dock="Left"
Orientation="Vertical"
HorizontalAlignment="Center"
HorizontalContentAlignment="Center"
Minimum="0"
Maximum="10"
Cursor="Hand"
Value="{Binding CurrentSliderValue}"
IsDirectionReversed="True"
IsSnapToTickEnabled="True"
Margin="10 10 0 10"/>
<Border DockPanel.Dock="Right" Background="Beige"
Padding="10"
Margin="10"
CornerRadius="5">
<StackPanel Height="700">
<TextBlock
Text="Test"
HorizontalAlignment="Center"
VerticalAlignment="Center"
FontSize="200" x:Name="TheNumber"/>
</StackPanel>
</Border>
</DockPanel>
</Window>
A stackpanel, no matter how you stretch it, will collapse around the children. you can't make it grow more than that. Basically, that "Height=700" is not helping you.
So either set VerticalAlignment on the StackPanel to "center" so that the stackpanel goes into the center of the dockpanel...or remove the stackpanel altogether and set VerticalAlignment="Center" on the TextBlock.
Seems I asked this question 10 months ago, I got the above scenario to work by replacing the StackPanel with DockPanel LastChildFill=True like this:
<DockPanel LastChildFill="True">
<TextBlock
DockPanel.Dock="Top"
Text="Test"
HorizontalAlignment="Center"
VerticalAlignment="Center"
FontSize="200" x:Name="TheNumber"/>
</DockPanel>
I stumbled across this which seems to work perfectly:
<Grid>
<TextBlock Text="My Centered Text"
TextAlignment="Center"
VerticalAlignment="Center"/>
</Grid>
The Grid ensures that the single TextBox within it fills the solitary cell in the grid and the VerticalAlignment in the TextBlock ensures that the text is centered within than.
Simply position/align your text horizontally however you require (the above snippet centers it in this axis also, but changing this doesn't alter the vertical centering).
Inside the StackPanel that surrounds the TextBlock, check out VerticalContentAlignment.