App.xaml.cs

using System;
using System.Windows;
using System.Windows.Threading;

namespace Skelton.WpfMahAppsPrismReactiveProperty
{
    public partial class App : Application
    {
        static readonly log4net.ILog Logger = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);
            DispatcherUnhandledException += Application_DispatcherUnhandledException;
            AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
        }

        protected override void OnExit(ExitEventArgs e)
        {
            base.OnExit(e);
            DispatcherUnhandledException -= Application_DispatcherUnhandledException;
            AppDomain.CurrentDomain.UnhandledException -= CurrentDomain_UnhandledException;
        }

        private void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
        {
            Logger.Error(e.ExceptionObject as Exception);
        }

        private void Application_DispatcherUnhandledException(object sender, DispatcherUnhandledExceptionEventArgs e)
        {
            e.Handled = true;
            Logger.Error(e.Exception);
        }
    }
}