Binding to WPF ViewModel properties
- by MartinHN
I'm just playing around with WPF and MVVM, and I have made a simple app that displays a Rectangle that changes color whenever Network availability changes.
But when that happens, I get this error: Cannot use a DependencyObject that belongs to a different thread than its parent Freezable.
Code
XAML
<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="400" Width="600">
<DockPanel LastChildFill="True">
<Rectangle x:Name="networkStatusRectangle" Width="200" Height="200" Fill="{Binding NetworkStatusColor}" />
</DockPanel>
</Window>
Code-behind
using System.Windows;
using WpfApplication1.ViewModels;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
DataContext = new NetworkViewModel();
}
}
}
ViewModel
using System.ComponentModel;
using System.Net.NetworkInformation;
using System.Windows.Media;
namespace WpfApplication1.ViewModels
{
public class NetworkViewModel : INotifyPropertyChanged
{
private Brush _NetworkStatusColor;
public Brush NetworkStatusColor
{
get { return _NetworkStatusColor; }
set
{
_NetworkStatusColor = value;
NotifyOfPropertyChange("NetworkStatusColor");
}
}
public NetworkViewModel()
{
NetworkChange.NetworkAvailabilityChanged += new NetworkAvailabilityChangedEventHandler(NetworkChange_NetworkAvailabilityChanged);
}
protected void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
{
if (e.IsAvailable)
{
this.NetworkStatusColor = new SolidColorBrush(Colors.Green);
}
else
{
this.NetworkStatusColor = new SolidColorBrush(Colors.Red);
}
}
public event PropertyChangedEventHandler PropertyChanged = delegate { };
public void NotifyOfPropertyChange(string propertyName)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
I assume that I should change the NetworkStatusColor property by invoking something?
