How to center BusyIndicator to the center of MainWindow? - wpf

Question

I created sample Wpf application and installed Extended WPF Toolkit (NuGet package). Here's my xaml code for showing BusyIndicator.
<Window x:Class="WpfApp3.Progress"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
xmlns:local="clr-namespace:WpfApp3"
mc:Ignorable="d"
WindowStyle="None"
BorderThickness="0"
Title=""
VerticalAlignment="Center"
HorizontalAlignment="Center"
SizeToContent="WidthAndHeight"
d:DesignWidth="300"
d:DesignHeight="300">
<xctk:BusyIndicator IsBusy="True"
HorizontalAlignment="Center"
VerticalAlignment="Center"></xctk:BusyIndicator>
</Window>
Showing the progress window is triggered with this code:
private void Button_Click(object sender, RoutedEventArgs e)
{
Progress w = new Progress
{
Owner = Application.Current.MainWindow,
WindowStartupLocation = WindowStartupLocation.CenterOwner
};
w.Show();
}
My question is simple. How to show BusyIndicator in the middle of the MainWindow screen. As Shown from the picture below it's not centered as it should be. Note that I use SizeToContent="WidthAndHeight"

Answer 1

Having a seperate window to display the busy indicator and will result in unwanted behaviour. What happens if the original window is maximised, moved etc.?
Consider adding the busy indicator to the main screen. Usually I create an overlay region that is used to display message dialogs, progress bars etc..
<Window>
<Grid>
<Application stuff ....>
</Application stuff>
<ContentControl regions:RegionManager.RegionName="OverlayRegion"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch" />
</Grid>
</Window>
I'm using Prism here but you can replace the ContentControl with anything, such as the BusyIndicator and manipulate the visibility of the control.

Answer 2

Solved it by removing Window.SizeToContent property and by adding VerticalAlignment and HorizontalAlignment properties to BusyIndicator (actually now I used spinner, but this doesn't make any difference in solution).
<Window x:Class="Test.Progress"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:extToolkit="http://schemas.microsoft.com/winfx/2006/xaml/presentation/toolkit/extended"
WindowStyle="None"
AllowsTransparency="True"
BorderThickness="0"
Title=""
WindowStartupLocation="CenterOwner"
ShowInTaskbar="False"
Background="Transparent"
d:DesignWidth="200"
d:DesignHeight="200"
MaxWidth="250"
MaxHeight="250">
<xctk:BusyIndicator IsBusy="True"
HorizontalAlignment="Center"
VerticalAlignment="Center"></xctk:BusyIndicator>
</Window>
The problem is because BusyIndicator was not designed to use it in separate window
The BusyIndicator is a ContentControl. What this means is that the BusyIndicator can contain a single child element within it?s open and closing tags.
Additionally if you do, first thing that is shown is small ui control (12x12 pixels) and after some latency finally the progress bar/busy indicator is shown.
By specifying SizeToContent='WidthAndHeight', xaml automatically resizes height and width relative to content. In this case (12x12) ui control is taken, and after some latency time finally as mentioned above busy indicator is shown. But by that time, the xaml ui renderer already applied SizeToContent and therefore you would have to manually re-position the progress bar.
I'm not really sure how xaml ui renderes works without specifying SizeToContent, but apparently it re-positions the busy indicator correctly after it is shown.