WPF

private void NavComplete(object sender, RunWorkerCompletedEventArgs e)
{
    worker.DoWork -= LoadTreeStuff; ;
    worker.RunWorkerCompleted -= NavComplete; ;
    if (e.Result != null)
    {
        MessageBox.Show(e.Result.ToString());
    }
    BusyIndicator = false;
    AppMessages.MessageObject.Send("ColumnsReady");
}

public static class MessageObject
    {
        public static void Send(object oPayload)
        {
            Messenger.Default.Send<object>(oPayload);<-------Errors
        }

<pre>
    public static void Register(object recipient, Action&lt;object&gt; action)
    {
        Messenger.Default.Register&lt;object&gt;(recipient, action);
    }

    public static void UnRegister(object recipient)
    {
        Messenger.Default.Unregister&lt;object&gt;(recipient);
    }
}</pre>

Quote:

The calling thread cannot access this object because a different thread owns it.

<Window x:Class="TestProject.Charts.ChartsWindow"
        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:testProjectCharts="clr-namespace:TestProject.Charts"
        mc:Ignorable="d"
        d:DataContext="{x:Static testProjectCharts:SampleModels.SampleChartsModel}"
        Title="ChartsWindow" Height="300" Width="600">
    <Grid>
        
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto" />
            <ColumnDefinition Width="*" />
        </Grid.ColumnDefinitions>
        
        <Grid>
            
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto" />
                <RowDefinition Height="*" />
            </Grid.RowDefinitions>

            <TextBlock Grid.Row="0" Text="Chart" Margin="6,6,6,0" />
            <ListBox Grid.Row="1" Name="NavigationListBox" VerticalAlignment="Stretch" Width="100" Margin="6,0,6,6" ItemsSource="{Binding Charts}">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding ChartName}" />
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>

        </Grid>

        <Grid Grid.Column="1">
            
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto" />
                <RowDefinition Height="Auto" />
                <RowDefinition Height="Auto" />
                <RowDefinition Height="*" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="Auto" />
                <ColumnDefinition Width="*" />
            </Grid.ColumnDefinitions>
            <Grid.Resources>
                <Style TargetType="TextBlock">
                    <Setter Property="Margin" Value="6,6,6,0" />
                    <Setter Property="VerticalAlignment" Value="Center" />
                </Style>
                <Style TargetType="TextBox">
                    <Setter Property="Margin" Value="6,6,6,0" />
                    <Setter Property="VerticalAlignment" Value="Center" />
                </Style>
            </Grid.Resources>

            <TextBlock Grid.Row="0" Grid.Column="0" Text="Chart ID:" />
            <TextBlock Grid.Row="0" Grid.Column="1" Text="[Bind to the selected chart's ChartId here]" />

            <TextBlock Grid.Row="1" Grid.Column="0" Text="Chart Name:" />
            <TextBox Grid.Row="1" Grid.Column="1" Text="[Bind to the selected chart's ChartName here]" />

            <TextBlock Grid.Row="2" Grid.Column="0" Text="Chart Description:" />
            <TextBox Grid.Row="2" Grid.Column="1" Text="[Bind to the selected chart's ChartDescription here]" />

        </Grid>

    </Grid>
</Window>

<TextBlock Text="v1.0.0.0" />

using System;

namespace TestProject
{
    public static class Startup
    {

        [STAThread]
        public static void Main()
        {
            // Create an instance of the About Model.
            AboutModel aboutModel = new AboutModel { Version = "v1.2.3.4" };

            // Create the About Window.
            AboutWindow aboutWindow = new AboutWindow(aboutModel);

            // Show the About Window
            aboutWindow.ShowDialog();
        }

    }
}

namespace TestProject
{
    public class AboutModel
    {
        public string Version { get; set; }
    }
}

<Window x:Class="TestProject.AboutWindow"
        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"
        mc:Ignorable="d"
        Title="About" Height="200" Width="300">
    <StackPanel>
        <TextBlock Text="Product Name " />
        <TextBlock Text="v1.0.0.0" />
    </StackPanel>
</Window>

namespace TestProject
{
    public partial class AboutWindow
    {
        public AboutWindow() : this(new AboutModel()) { }

        public AboutWindow(AboutModel model)
        {
            InitializeComponent();
            _model = model;
        }

        private readonly AboutModel _model;
        public AboutModel Model => _model;
    }
}