When my application starts up I don't want a visible Chart as there's nothing that's been processed. I thought I can "hide" the Chart in an Expander - (simple minded, perhaps). The following code appears to break OxyPlot:
<StackPanel Grid.Row="0" Grid.Column="4" Orientation="Horizontal">
<Expander ExpandDirection="Right">
<oxy:Plot Grid.Row="0" Grid.Column="4" Title="Plot"
x:Name="ChartPlot" Title="Ein Grafik"
Model="{Binding PlotModel}">
</oxy:Plot>
</Expander>
</StackPanel>
What don't I understand about either the Expander or the OxyPlot control?
Or perhaps there are "better practices" to hide Content until it's ready?
Give your plot a size. As is, it thinks it has 0 space. Or enclose it in a grid that has a size.
Related
Say I have a simple Windows 10 UWP app
<Page
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
<!-- etc -->
>
<Grid>
<ListView>
<TextBlock Text="Sample text"/>
<TextBlock Text="Sample text"/>
<TextBlock Text="Sample text"/>
<!-- & many more -->
</ListView>
</Grid>
</Page>
The large number of ListView items causes it to overflow and scroll, as expected:
However, if I need to add another control as a sibling of the ListView, like so (replacing the Grid with a StackPanel for simplicity)
<Page...>
<StackPanel>
<ListView>
<TextBlock Text="Sample text"/>
<TextBlock Text="Sample text"/>
<TextBlock Text="Sample text"/>
...
</ListView>
<StackPanel>
<TextBlock Text="StackPanel at the bottom"/>
<Button Content="Click me"/>
</StackPanel>
</StackPanel>
</Page>
then the scrollbar disappears and the ListView isn't scrollable anymore. The content just gets clipped / cut off past the bottom of the window.
What's going on here and how can I make it scroll again?
The key to this is the ScrollViewer control. The reason ListViews and GridViews can scroll in the first place is because they have a ScrollViewer built in.
When you place a ListView inside a parent layout panel (e.g. a StackPanel or a Grid row), if the ListView height is greater than the viewport, the parent panel becomes the full height of the ListView. But StackPanel doesn't implement ScrollViewer so it can't scroll, and you end up with a StackPanel extending off the bottom edge of the viewport.
The fix is simple: put the parent layout panel in question inside a ScrollViewer
<Page...>
<ScrollViewer VerticalScrollBarVisibility="Auto"> <!--default is "Visible"-->
<StackPanel>
<ListView>
<TextBlock Text="Sample text"/>
<TextBlock Text="Sample text"/>
<TextBlock Text="Sample text"/>
...
</ListView>
<StackPanel>
<TextBlock Text="StackPanel at the bottom"/>
<Button Content="Click me"/>
</StackPanel>
</StackPanel>
</ScrollViewer>
</Page>
ScrollViewer API reference - MSDN
Going to add more context to binaryfunt's answer: It depends on the layout logic of the panel you're using!
To note beforehand: ListView internally has it's own ScrollViewer by default.
When laying out it's children, a Grid will typically tell its children they should fit inside the bounds the grid. In the case of the ListView, it's happy to do this, and it's own internal ScrollViewer handles it's children scrolling.
StackPanel on the other hand tells its children they have virtually infinite space to layout in in it's stacking direction - so your ListView has no idea it has to constrain itself to the height of your StackPanel because the StackPanel does not tell it do so and so the ListView never needs to use it's own ScrollViewer as it thinks it has infinite space.
Now, put a StackPanel in a ScrollViewer by itself doesn't help - if you put that ScrollViewer inside a StackPanel you have the same problem as the ListView does - it thinks it has infinite space and so never needs to scroll it's content. But, put the ScrollViewer in a Grid and the grid will give the ScrollViewer a defined size to layout in, and so anything inside the ScrollViewer will now scroll if it get's too big.
Put a ListView inside this StackPanel inside this ScrollViewer? The ListView still thinks it has infinite space and so never needs to use its own scroller, BUT it's also disables and virtualization and performance enhancements the ListView would normally have, as they rely on it's interal ScrollViewer actually being put a too use.
(binaryfunt's XAML answer will work.)
Currently I got a requirement to implement a control something like traditional masked text box. But unfortunately there is no first party control (some third party paid control is available like Component 1) available in uwp. If anybody has any idea to create the same please share.
You can make a TextBox background transparent and have a TextBlock behind it with your watermark text. Bind the visibility to the TextBox Text.IsEmpty property using a BooleanToVisibilityConverter
<Grid Grid.Row="0" Margin="5" Background="White">
<TextBlock VerticalAlignment="Center" Margin="3"
Foreground="SteelBlue"
Visibility="{Binding ElementName=MyTextBox, Path=Text.IsEmpty, Converter={StaticResource BooleanToVisibilityConverter}}">Type in here...</TextBlock>
<TextBox Background="Transparent"
x:Name="MyTextBox"/>
</Grid>
In your resources:
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
Have a look at PlaceHolderText Property on TextBox control.
I'm making a news feed app, which periodically adds new content to the top of the list. When I check for new items, there might be dozens or just one. What I'd like is for the oldest of the new items to peek into view so they can continue scrolling up for newer stories.
Sadly this doesn't come for free with the platform. However whats interesting is that it does come for free at the bottom of the list. If you add items to the bottom of the list they peek in properly with a nice animation. If you add items to the top of the list they just blink into place.
Workarounds available? I'm feeling this is more of a platform bug - I'm setting KeepItemsInView but if I'm at the top of the list it doesn't keep the item I'm looking at in view.
Repro video: http://1drv.ms/1PP8AZz
Full source: http://1drv.ms/1PP8FfT
<ListView Grid.Row="1" ItemsSource="{x:Bind Items}" Padding="0,100,0,100">
<ListView.ItemTemplate>
<DataTemplate >
<Grid Margin="10">
<Image Source="{Binding}"/>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<ItemsStackPanel Orientation="Vertical" ItemsUpdatingScrollMode="KeepItemsInView" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
Can anybody tell me how to clone UIElement in SILVERLIGHT ?. I dug a lot in the google but I'm not able to find relevant solution, everywhere I'm just getting solution to clone UIElement in WPF, however same is not applicable in the Silverlight.
I need to add the a UIElement in the same grid's next rows on click of a + button eachtime.
Plz help..any answer will be appreciable
Thanks
GK
There is no facility to do that.
In your scenario you can use an ItemsControl (directly or as a ListBox, for example) and provide your to-be-duplicated piece of UI as a datatemplate:
<ItemsControl ItemsSource="{Binding MyData}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<TextBlock Text="{Binding LabelText}" />
</Grid>
<DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
This is the most typical way of doing it, but you will need to know about databinding to do it.
There is also the possibility of factoring out your to-be-duplicated piece of UI in a UserControl and add that programmatically multiple times.
I have the following problem. I keep getting 'ToolTip' cannot have a logical or visual parent error when i try to style tooltip for the toggle button. What went wrong? When i take out the tooltip control under ToggleButton.ToolTip it works !
<ToggleButton x:Name="toggle" OverridesDefaultStyle="True" Template="{StaticResource ExpanderToggleButton}" Margin="0,4,0,0" VerticalAlignment="Top" IsChecked="{Binding IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
<ToggleButton.ToolTip>
<ToolTip Style="{StaticResource tooltipstyle}">
<TextBlock Background="Transparent"/>
</ToolTip>
</ToggleButton.ToolTip>
</ToggleButton>
If you write code like this using property element syntax, you call already the constructor of the ToolTip class.
<ToggleButton.ToolTip>
<TextBlock></TextBlock>
</ToggleButton.ToolTip>
There is no need to instantiate another ToolTip inside like this...
<ToggleButton.ToolTip>
<ToolTip Style="{StaticResource tooltipstyle}">
<TextBlock Background="Transparent"/>
</ToolTip>
</ToggleButton.ToolTip>
Besides, on my system (using .NET 4.5) there is no error.
It seems that WPF can handle both versions meanwhile as intended by the developer.