Develop Reference

WPF TabControl header issue

I am making an app in WPF that displays an image which can be dragged and zoomed. Bottom, right and upper sides contain some UI elements like buttons and in the center I have a TabControl to which I add TabItems in the code of ViewModel. These TabItems consists of their content (an image) and a header where I have tab buttons. The problem I have is that an image I drag covers the header but not the buttons as you can see on the screenshot. The behavior I expect is to have this image hidden underneath the entire header, not only buttons. It only happens with the bottom side. When I drag the image to the top or right it gets hidden behind the sides like it's supposed to.
Header issue
I tried to change its background, opacity and ZIndex but nothing worked for me.
Here is my code.
XAML:
<TabControl Grid.Row="1" Grid.Column="0" TabStripPlacement="Bottom" Background="LightGray" ItemsSource="{Binding LayoutTabs}"
SelectedIndex="0" SelectedItem="{Binding SelectedTab, Mode=OneWayToSource}"/>
C#:
LayoutTabs = new BindableCollection<TabItem>();
for (int i = 0; i < _content.LayoutImages.Count; i++)
{
DrawingImage drawing = _content.LayoutImages.ElementAt(i);
Image image = new Image() { Source = drawing };
image.MouseMove += OnMouseMove;
var container = new LayoutContainer()
{
Background = Brushes.WhiteSmoke,
Child = image,
Focusable = true,
};
var tabItem = new TabItem()
{
Header = _content.GetLayoutName(i),
Content = container
};
LayoutTabs.Add(tabItem);
}

That behaviour is due to the headerpanels background being set to transparent in the default control template. If you right click the tabcontrol in the Designer window (not xaml editor) and click on Edit Template->Edit a Copy you get a copy of that tempalte and can then modify the headerpanel with your BackgroundColor and if need be increase the Zindex:
[....]
//this is the line to make your changes on:
<TabPanel x:Name="headerPanel" Background="Transparent" Grid.Column="0" IsItemsHost="true" Margin="2,2,2,0" Grid.Row="0" KeyboardNavigation.TabIndex="1" Panel.ZIndex="1"/>
[....]

UWP XAML ScrollViewer how to show visual indicator of scrollable content

Is there a way to visually indicate that there is scrollable content below the visible area of a <ScrollViewer>?
I see this effect in applications like Microsoft Teams. A shadow appears at the bottom of the scrollable area to indicate that more content is present.
None of the properties of <ScrollViewer> seem to be a clear match. But I'm hoping I can avoid having to programmatically show/hide an element below the <ScrollViewer> based on the scroll position.

I have to say that currently there is no built-in API in ScrollViewer that could directly show a shadow there if the content is not ended.
You might still need to check it programmatically by handling the ViewChanged event of the ScrollViewer and add a custom element.
You could use the following code to check if the ScrollViewer reaches the end:
<Grid>
<ScrollViewer Name="MyScrollViewer" ViewChanged="MyScrollViewer_ViewChanged">
<Rectangle
x:Name="MyRectangle"
Width="3000"
Height="3000"
Fill="Blue"
Margin="20" />
</ScrollViewer>
</Grid>
Code behind:
private void MyScrollViewer_ViewChanged(object sender, ScrollViewerViewChangedEventArgs e)
{
var verticalOffset = MyScrollViewer.VerticalOffset;
var maxVerticalOffset = MyScrollViewer.ScrollableHeight;
if (maxVerticalOffset < 0 || verticalOffset == maxVerticalOffset)
{
// content reaches the end
MyRectangle.Fill = new SolidColorBrush(Colors.Red);
}
else
{
// content does not reach the end
MyRectangle.Fill = new SolidColorBrush(Colors.Blue);
}
}

Make XAML control with WebView full screen

Ultimate Goal
When a user clicks the Expand button, I want the WebContainerControl to be full screen, be focused, not allow scrolling in the ScrollViewer, and overlap the title grid (with the back button, page title, etc.)
Basically, it should be like clicking on a photo in a nice photo viewing app. Exapnd to full screen, have an X button in the top right corner and when you click it, it goes back to the regular view.
Problem
Since it's a WebView, I can't simply pass the view to a popup (It gives me an invalid args exception since the current browsing session can't be passed by reference... they logged in on a site, so it would be insecure I assume)
I have a XAML control with a webview in it:
<UserControl x:Class="App.WebContainerControl">
<Grid x:Name="grdWebContainer">
<StackPanel>
<Button Click="btnExpandView_Click"/>
<WebView x:Name="wvSite"/>
</StackPanel>
</Grid>
</UserControl>
Here is an example view it would be loaded into:
<Grid x:Name="grdMain">
<Grid.RowDefinitions>
<RowDefinition Height="140"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<!-- Title Grid -->
<Grid x:Name="grdTitleBar" Grid.Row="0">
<TextBlock Text="App Title"/>
</Grid>
<!-- Web Views -->
<Grid Grid.Row="1">
<ScrollViewer>
<StackPanel>
<controls:WebContainerControl x:Name="First Site"/>
<controls:WebContainerControl x:Name="Second Site"/>
</StackPanel>
</ScrollViewer>
</Grid>
</Grid>
What I have so far
So far, when they press the Expand button, it makes the control full screen (using Current.Window.Bounds)
Then, I pass the event that the button is pressed to the main view:
private void OnAccount_Expanded(object sender, ExpandedEventArgs args) {
// Expanded button is pressed and control is made full screen
if (args.IsExpanded) {
// Hide titlebar
grdMain.RowDefinitions[0].Height = GridLength.Auto;
grdTitleBar.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
}
else {
// show titlebar again
GridLength gl = new GridLength(140);
grdMain.RowDefinitions[0].Height = gl;
grdTitleBar.Visibility = Windows.UI.Xaml.Visibility.Visible;
}
}
The Question
Right now, it makes it full screen, but I can still scroll. Any idea how to set the ScrollViewer to horizontally center on the control? If anyone has a better idea on how to achieve my Ultimate Goal, you would make me one happy camper! (Remember, it won't allow me to pass my control around, only manipulate it)

If I understand well, Put name on you Scroll Viewer
<ScrollViewer Name="uiScroll" >
............
</ScrollViewer >
When you doing full screen set visibility of you scrollBar
uiScroll.HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled;

How to disable background GUI interaction when popup dialog opens

Is there any way to disable background GUI interaction when popup dialog open?
My popup dialog is a UserControl so cannot manually set the content of that page using isEnabled to false property as my popup dismiss login is on that usercontrol page.
Thanks in advance.

You can set a background grid on your user control and on the background grid set IsHitTestVisible="False" Your popover will be defined after the grid so it's placed on top and can receive user input.
To disable the app bar, you can disable that when the popup opens. If there is a different app bar on every page then it's possible you could write a method which would find any app bar in the UI and disable it until the popup window is closed.
WinRTXAMLToolkit has a visual tree helper class, which could be used to find the app bars.
var AppBars = Window.Current.Content.GetDescendentsOfType<type of app bar>();
foreach(var appBar in AppBars)
{
appBar.IsEnabled=false;
}
When the popup window is hidden, re-enable the app bars.

In your event handler (Button) that opens the popup, write the following piece of code.
private void PopupButton_Click(object sender, RoutedEventArgs e)
{
this.IsHitTestVisible = false;
this.Opacity = 0.5;
MyPopup.IsOpen = true;
}
And when your popup closes, you may catch the event and write the following code.
private void MyPopup_Closed(object sender, object e)
{
this.IsHitTestVisible = true;
this.Opacity = 1;
}
This would give the same visual effect that you get when once opens a Dialog.

I have used SwapChainPanel to disable parent view content user interaction. Also I have added gray overlay while my custom popup is shown.
<SwapChainPanel x:Name="DirectXPanel" Visibility="{Binding IsOpen, Converter={StaticResource BooleanToVisibilityConverter}}" >
<Border CornerRadius="5" Opacity="0.60" Background="#000000" ></Border>
</SwapChainPanel>
<UserControls:CustomLoginPanel x:Name="CustomLoginPanel" Height="220" Width="400"
HorizontalAlignment="Center"
VerticalAlignment="Center"
Grid.Row="0"
IsOpen="{Binding IsOpen, Mode=TwoWay}"
Margin="0,70,0,0"/>
Here ProgressDialog is my custom popover which I want to show while user is login.
SwapChainPanel is going to cover entire window while custom popover is shown. By default it is hidden.
IsOpen is property exist in my view. This property is used to Show/Hide the Popover.
"BooleanToVisibilityConverter" is a converter used to convert boolean to Visibility
BooleanToVisibilityConverter.cs:
public sealed class BooleanToVisibilityConverter:IValueConverter
{
public object Convert(object value, Type targetType, object parameter, string language)
{
return (value is bool && (bool)value) ? Visibility.Visible : Visibility.Collapsed;
}
public object ConvertBack(object value, Type targetType, object parameter, string language)
{
return value is Visibility && (Visibility)value == Visibility.Visible;
}
}

A workaround to disable the space that your popup control is not taking could be actually taking that space, and making the "unused" space transparent or partially transparent to get that nice message dialog effect.
For example, if your popup looks like a classic winrt message dialog (full width and vertically centered), make your popup control have the same width and height as your background and make the popup's content a grid with 3 row definitions. Place the actual content in the middle row, so it will be vertically centered. Then place a grid in the first row with black background color and opacity of 0.4, and with a rowspan of 3 so it will take all the space. Once you Open the popup, it will take focus over the whole background so the user cannot interact with it but still being able to see the background that the actual content doesn't overlap.
Here a simple example of what i say:
<UserControl ...>
<Popup x:Name="PopupControl"
IsLightDismissEnabled="False"
Loaded="PopupControl_Loaded">
<!-- The content of the Popup, a grid with 3 rows. The second row takes half of the space from the popup -->
<Grid x:Name="PopupGrid">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="2*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<!-- Place a grid on the first row with black background, a rowspan of 3 will take all the rows so the user cannot interct with the actual background. -->
<Grid Grid.RowSpan="3"
Background="Black"
Opacity="0.4" />
<!-- Here place the actual content of your popup. -->
<Grid Grid.Row="1" Background="White">
[Acutal content of the popup]
</Grid>
</Grid>
</Popup>
</UserControl>
In the code behind of the user control:
// Finally make the popup control full screen.
private void PopupControl_Loaded(object sender, RoutedEventArgs e)
{
this.PopupGrid.Height = Window.Current.CoreWindow.Bounds.Height;
this.PopupGrid.Width = Window.Current.CoreWindow.Bounds.Width;
}

Scrollbars in a dynamically filled stack panel

I am new for WPF so apologies if the answer is so obvious.
I got a WPF resizable window with a single stack panel control that is stretched vertically and horizontally to fill the window.
On window activated event, I use ".Children.Add" to add button controls to the panel. I have no idea how many buttons will be there at runtime so I checked "CanVerticallyScroll" in the panel. ScrollViewer.VerticalScrollBarVisibility is set to Visible by default.
I am still not seeing scroll bars at runtime though.
What properties did I miss to show scrolling panel with buttons?
Thanks
XAML:
<Window x:Class="ResMed.Ecp.Utility.ConnectionWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="ConnectionWindow" Height="388" Width="641.6" Activated="Window_Activated">
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition Height="359*"/>
</Grid.RowDefinitions>
<StackPanel x:Name="pnlConnectionButtons" Margin="10,10.2,10.2,10" Grid.Row="1" CanVerticallyScroll="True"/>
</Grid>
</Window>
Code behind:
private void Window_Activated(object sender, EventArgs e)
{
for (int i = 0; i < 20; i++)
{
Button btn = new Button();
btn.Content = "Hello";
pnlConnectionButtons.Children.Add(btn);
}
}

Place your StackPanel inside a ScrollViewer:
<ScrollViewer>
<StackPanel>
<Button Content="Hello World"></Button>
...
...
</StackPanel>
</ScrollViewer>
You can also remove CanVerticallyScroll="True". From MSDN:
This property is not intended for use in your code. It is exposed publicly to fulfill an interface contract (IScrollInfo). Setting this property has no effect.