c# WPF Update Window on Button Click

Question

I have been messing around with c# in Visual Studio (rather new to it) and have been trying to build an application using WPF and I cannot seem to figure out how in my environment to update my WPF view when a button is clicked. I have tried to cull my code down to the relevant information

I have the following scenario in my .cs file

class Program
{

    [STAThread]
    static void Main(string[] args)
    {

        try
        {
            using (VMS.TPS.Common.Model.API.Application app = VMS.TPS.Common.Model.API.Application.CreateApplication("null", "null"))
            {
                Execute(app);
            }
        }
        catch (Exception e)
        {

            MessageBox.Show(e.ToString());

        }
    }


    static void Execute(VMS.TPS.Common.Model.API.Application app)
    {
        Window window = new Window();
        MainWindow mainWindow = new MainWindow(app);
        mainWindow.evalButton.Click += Eval_Click //Button defined in .xaml

        //Add a bunch of items

        window.ShowDialog();
    }
    public static void Eval_Click(object sender, EventArgs e)
    {
        //need to add some more stuff to mainWindow and update window
    }
}

My MainWindow.xaml file has class defined as .MainWindow and the MainWindow.xaml.cs file is as follows

public partial class MainWindow : UserControl
{

    private VMS.TPS.Common.Model.API.Application _application;

    public MainWindow(VMS.TPS.Common.Model.API.Application Application)
    {
        _application = Application;


        InitializeComponent();

    }

}

Answer 1

If you want your View layer to update on button press, you can re-assign the DataContext . For example:

public static void Eval_Click(object sender, EventArgs e)
{
    this.DataContext = new MyDataContext();
}

But if you're following the MVVM pattern, your DataContext should inherit from the INotifyPropertyChanged interface and you can also just call a PropertyChangedEventHandler event to update specific bindings in the View layer. For example:

public event PropertyChangedEventHandler PropertyChanged;  
private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")  
{  
    PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
public void UpdateView()
{
    NotifyPropertyChanged("foo");
    NotifyPropertyChanged("bar");
}  

...

public static void Eval_Click(object sender, EventArgs e)
{
    (this.DataContext as MyDataContext).UpdateView();
}