Threadabortexception when calling showdialog in C#

Question

I have an application that parses a large XML file and builds WPF UI controls based on that content. This task usually takes about 15 - 30 seconds. In order to inform the user about a running task, I display a simple intermediate progress dialog window, like:

Thread progressDialogThread = new Thread(() =>
{
    Window window = new Window
    {
        Content = new ProgressDialog(),
        Height = 100,
        Width = 150,
        WindowStartupLocation = System.Windows.WindowStartupLocation.CenterScreen
    };
    window.ShowDialog();
});

progressDialogThread.SetApartmentState(ApartmentState.STA);
progressDialogThread.IsBackground = true;
progressDialogThread.Start();

buildUI();

progressDialogThread.Abort();

This works, but I sometimes get a ThreadAbortException on progressDialogThread.Start(), when the XML should be parsed once again.

Does anyone know a better approach to "close" the progress dialog?

Since the controls have to be built on the main UI thread, I can not use the backgroundworker...

The progress dialog itself in XAML looks like:

<UserControl x:Class="MyDialog.ProgressDialog"
        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:local="clr-namespace:MyDialog"
        mc:Ignorable="d"
        Background="{DynamicResource MaterialDesignPaper}"
        TextElement.Foreground="{DynamicResource MaterialDesignBody}"
        Height="100" Width="150">
    <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
        <Label HorizontalAlignment="Center">Please wait</Label>
        <ProgressBar
          Style="{StaticResource MaterialDesignCircularProgressBar}"
          Value="0"
          IsIndeterminate="True" Width="40" Height="41" Margin="55,0" HorizontalAlignment="Center" VerticalAlignment="Center" />
    </StackPanel>
</UserControl>

Answer 1

Do not abort a thread, that should be avoided.

If you want to close a Window, you call Close on it.

Oh, it is created by another thread? Alright, that is why the Window has a Dispatcher, you use BeginInvoke and it will run the callback on that thread.

In fact, there is a chance you do not need to create the Window in another thread※. You can create it in the main thread and have a background thread interact with it via BeginInvoke.

※: If you have the main thread busy and want the Window in another thread so the main thread does not block it (or viceversa), you probably should be using a BackgroundWorker (as Caius Jard suggests) instead of having a UI thread busy.