WPF C# INotifyPropertyChanged doesn't fire up - wpf

Question

I am building a WPF application that as part of its flow, checks for network connectivity and display the IP address in a TextBlock.
Now I am trying to update the TextBlock Text property everytime the IP address changes for whatever reason.
I have the IP address change working fine, but i could not get INotifyPropertyChanged to work.
I read all the possible solutions and implementations but I couldn't come up with a working code.
The public property gets the value from a static string from the Network Helper class.
So, the code:
public partial class MainWindow : Window, INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
}
public MainWindow()
{
InitializeComponent();
DataContext = this;
}
public string ipAddress
{
get { return NetworkStatus.localIP; }
set
{
if (value != NetworkStatus.localIP)
{
NetworkStatus.localIP = value;
NotifyIPChanged("IpAddress");
}
}
}
private void NotifyIPChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
XAML:
<TextBlock x:Name="ipTxt"
TextWrapping="Wrap"
HorizontalAlignment="Left"
VerticalAlignment="Center"
Text="{Binding DataContext.ipAddress}"
Height="30"
Width="110"
Margin="-30,10,0,-10"
/>
UPDATE
NetWorkStatus.cs -- static bool IsNetworkAvailable()
...
if (statistics.BytesReceived > 0 || statistics.BytesSent > 0)
{
IPHostEntry host = Dns.GetHostEntry(Dns.GetHostName());
localIP = host.AddressList.FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork).ToString();
return true;
}
As you can see this method sets a static string "localIP". This is then evaluated by IpAddress property.
Why the TextBlock Text property doesn't get updated when the IP Address changes?

Answer 1

Rename the property to IpAddress so that it adheres to widely accepted naming conventions.
public string IpAddress
{
get { return NetworkStatus.localIP; }
set
{
if (value != NetworkStatus.localIP)
{
NetworkStatus.localIP = value;
NotifyPropertyChanged();
}
}
Use the CallerMemberName attribute on the propertyName parameter of your notification method, so that you do not have to write the name explicitly.
using System.Runtime.CompilerServices;
...
private void NotifyPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
Bind it correctly. The current DataContext is already used as source object of the Binding. You must not add it to the property path.
<TextBlock Text="{Binding IpAddress}" ... />
In a possible next step you might want to separate the view from the view model and put the property in a separate class:
public class ViewModel : INotifyPropertyChanged
{
public string IpAddress
{
get ...
set ...
}
...
}
and assign the Window's DataContext to an instance of the view model class:
public MainWindow()
{
InitializeComponent();
DataContext = new ViewModel();
}

Answer 2

I think you need to take a closer look to how WPF works.
As a remark, there is no need to implement INotifyPropertyChanged in code behind. If you are using events, then you can automatically refresh the properties of the targeted UI element.
However, using code behind is not a good practice in our days. You should take a look at MVVM pattern. You have there a Model, View and ViewModel. The ViewModel should implement INotifyPropertyChanged.
The fact is that your code is in my opinion absolutely wrong. The naming is not fine : when you implement INotifyPropertyChanged you should not implement it only for a property, and the name should not look like : NotifyIPChanged, instead you should use RaisePropertyChanged, NotifyPropertyChanged or OnPropertyChanged. In setters you should not refresh something else, but only the property that you are targeting, because otherwise the Single Responsability principle is violated, as in your case. Also a bad practice is to bind to Code Behind.
I hope this post would make you to read more about MVVM and WPF. Good luck!

Answer 3

is it possible that the Event doesnt react, because the first letter of IpAdress is an Upper?
NotifyIPChanged("IpAddress");
public string ipAddress
Text="{Binding DataContext.ipAddress}"