Develop Reference

Override MediaElement on top of Webview2

I created a WPF project in which I need display two StackPanels like this:
This screen is child of main Grid
StackPanel 1 will be displayed without any alternation of width and height and I need to display the entire second StackPanel on top of previous StackPanel. Using Canvas and DockPanel doesn't help me in this case.
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel VerticalAlignment="Center" Grid.Row="0" x:Name="web1">
<wv2:WebView2 Name="MyWebView"
Height="800" >
</wv2:WebView2>
</StackPanel>
<StackPanel Grid.Row="0" x:Name="videoPlayerPanel">
<Canvas >
<local:VideoPlayer x:Name="videoPlayer" Background="AntiqueWhite"/>
</Canvas>
</StackPanel>
</Grid>

I agree with #thatguy answer , if we use the zIndex we can overlap the element in WPF, But the question here is related to webview2 and mediaElement.
As of now webview2 not allow another element to come on top.
So there is no way to display your mediaElement on top of webview as of now.
Reffer to this Link for this issue : Webview2 issue
You can try to display mediaElement using popup but this will give other problems
I think this is the only answer to your question right now .

The order in which you define the StackPanels inside the Grid matters. The next item is displayed above the previous one. In your example, videoPlayerPanel will be above web1, because it is defined after web1. There are two options to alter this behavior.
Change the order, define videoPlayerPanel before web1, to display web1 above videoPlayerPanel.
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel Grid.Row="0" x:Name="videoPlayerPanel">
<Canvas >
<local:VideoPlayer x:Name="videoPlayer" Background="AntiqueWhite"/>
</Canvas>
</StackPanel>
<StackPanel VerticalAlignment="Center" Grid.Row="0" x:Name="web1">
<wv2:WebView2 Name="MyWebView"
Height="800" >
</wv2:WebView2>
</StackPanel>
</Grid>
Define the Z-Order explicitly by setting a ZIndex for the items.
Gets or sets a value that represents the order on the z-plane in which an element appears. [...] The greater the value of a given element, the more likely the element is to appear in the foreground.
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel VerticalAlignment="Center" Grid.Row="0" x:Name="web1" ZIndex="1">
<wv2:WebView2 Name="MyWebView"
Height="800" >
</wv2:WebView2>
</StackPanel>
<StackPanel Grid.Row="0" x:Name="videoPlayerPanel">
<Canvas >
<local:VideoPlayer x:Name="videoPlayer" Background="AntiqueWhite"/>
</Canvas>
</StackPanel>
</Grid>
The default ZIndex is zero, and that explains why the order in the Grid matters.
Members of a Children collection that have equal ZIndex values are rendered in the order in which they appear in the visual tree. You can determine the index position of a child by iterating the members of the Children collection.

WPF shrink other conent when Expander is Expanded

Whenever Expander is expanded I would like to shrink grid cell above containing ListBox, so that you can always access every ListItem(if the listbox's grid cell would not shrink, lowest part would be inacessible). To illustrate:
item item *scrollbar*
item -> item *scrollbar*
item expanderItems
expander expander
I found bunch of threads for resizable expander, but none mentioning resizing other content. The problem is, grid containing listbox in 1st row and expander in 2nd with 2nd row Height set to Auto do not resize itself when expander is expanded.
<Grid.RowDefinitions>
<RowDefinition Height="1*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
I managed to code an ugly workaround using Expanded/Collapsed events:
private void Expander_Expanded(object sender, System.Windows.RoutedEventArgs e)
{
//grid1.Height is named content of expander
this.LayoutRoot.RowDefinitions[1].Height = new GridLength(this.LayoutRoot.RowDefinitions[1].ActualHeight + grid1.Height, GridUnitType.Pixel);
this.LayoutRoot.RowDefinitions[0].Height = new GridLength(1, GridUnitType.Star);
}
What would be the proper way? Preferably with no code behind and more "automated".
EDIT: xaml
<Grid x:Name="LayoutRoot">
<Grid.RowDefinitions>
<RowDefinition Height="1*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Expander Header="Expander" Margin="0" Grid.Row="1" VerticalAlignment="Bottom" Height="23" Panel.ZIndex="1" ExpandDirection="Up" Grid.RowSpan="2" Expanded="Expander_Expanded" Collapsed="Expander_Collapsed">
<Grid x:Name="grid1" Background="#FF762CF7" Height="100" Margin="0,-100,0,0"/>
</Expander>
<ListBox Margin="0" Background="#19FFFFFF">
<Button Height="150" Width="100"/>
<Button Height="150" Width="100"/>
<Button Height="150" Width="100"/>
</ListBox>
<Grid Margin="0" Grid.Row="1" Background="#FFAEFFAE"/>
<Grid Margin="0" Background="#FFFFD8D8"/>
</Grid>

The main problem you have is setting the Height property of the Expander. It changes its height when you expand it. But if you are setting it, it has to respect the height you gave it and cannot properly expand.
Instead of setting the Height, I would set the MinHeight (or completely remove height constraints, depending on what you want to do).
Additionally you should remove the Margin of the grid inside the expander.

Using multiple frame in a wpf window

I'm developing an application using WPF by c#.
I have 2 frames next to each other. The above will not change and just updated(like Facebook toolbar).
The bottom frame will change by clicking on some buttons. (it is something like masterpage in ASP).
I don't want to set a height and width for window or for frames. The problem is when I make the window full screen there is a space between two frames.
However none of the vertical/horizontal alignment stretch does not work.
<window>
<Frame VerticalAlignment="Top" Background="Crimson" />
<Frame VerticalAlignment="Bottom" Background="Black"
/>
</Window>
I want to create something like the this site as you see. the notify section and the main page.
EDIT:
i can put them next to each other just by set the height, but when i make full the window the heights stay and the yellow space becomes appear, so i want to find a way to put them Exactly next to each other in every window size.

As Mitch noted in the comments, you could place the two frames in a grid instead, and let the grid size the items.
<Window>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Frame Grid.Row="0" Background="Crimson" />
<Frame Grid.Row="1" Background="Black" />
</Grid>
</Window>

<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Frame Grid.Row="0" Background="Crimson" />
<Frame Grid.Row="1" Background="Black" />
</Grid>

ListView Inside a Grid inside a ScrollViewer

I have a ListView inside a Grid which in turn is inside an "overall ScrollViewer".
Users should be able to scroll across the entire page horizontally and then scroll vertically down several child list like elements. While I am able to scroll horizontally, placing the outer ScrollViewer around the page content breaks my ListViews
Here is a cut down version of my XAML setup:
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid.RowDefinitions>
<RowDefinition Height="140" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<TextBlock x:Uid="Title" Text="Title"/>
<ScrollViewer Grid.Row="1" ZoomMode="Disabled"
VerticalScrollBarVisibility="Hidden"
HorizontalScrollBarVisibility="Auto"
VerticalScrollMode="Disabled"
HorizontalScrollMode="Enabled">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="380" />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<!--My List-->
<ListView x:Name="MyList" Grid.Column="0" />
<Grid x:Name="AppointmentDetailView" Grid.Column="1">
<!--Some other stuff-->
</Grid>
</Grid>
</ScrollViewer>
</Grid>
If I set a fixed height on any parent of the ListView or the ListView itself the scrolling works as expected but fixing the height is undesirable for screens of varying sizes. I tried binding to the ActualHeight of the ListViews parents but no luck.
It seems like the ScrollViewers children are not constrained to the height available even when the ScrollViewer.VerticalScrollMode is disabled. Seems rather odd to me, I would have expected the ScrollViewer's layout logic to be similar to Grid in the direction it has been disabled.
Any help with this is appreciated, Thank you!

I found a workaround that involves wrapping my ScrollViewer in a Grid and binding to the outer Grids ActualHeightProperty on the child element of the ScrollViewer. its a bit of a hack but does what I need it to and goes something like this
<Grid x:Name="ScrollViewerContainer" ...>
<ScrollViewer VerticalScrollMode="Disabled" ...>
<!--Page Content-->
<Grid Height="{Binding ActualHeight, ElementName=ScrollViewerContainer}" ...>
....
Personally I feel like the ScrollViewer should not allow its children to determine its Width/Height when the scroll mode is disabled in a particular direction as it breaks nested ScrollViewer's. It should revert back to the available space. But hey, I'm not Microsoft..

Attach element position to another that has dynamic height WPF

I have two elements inside a Grid, the first one has a dynamic height and the second has a fixed height. When the user resizes the window the first element is supposed to grow bigger until the scrollbar does not show. Here's the code:
<Grid VerticalAlignment="Stretch">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="40" />
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<ScrollViewer>
<!-- MORE STUFF HERE -->
</ScrollViewer>
</Grid>
<Button Grid.Row="1" Width="126" HorizontalAlignment="Left" VerticalAlignment="Top" />
</Grid>
And when it's small looks like this:
When it's big it looks like this:
How can I attached the Button the bottom of the first element, or make the first element stop growing after the content is displayed?

Set the Grid's VerticalAlignment to Top instead of Stretch:
<Grid VerticalAlignment="Top">
...
</Grid>