[#43] App: Use FileSystemWatcher to renew contexts on demand

Elwig/Windows/ContextWindow.cs

@@ -2,25 +2,14 @@ using Elwig.Helpers;
 using System;
 using System.Threading.Tasks;
 using System.Windows;
-using System.Windows.Threading;
 
 namespace Elwig.Windows {
     public abstract class ContextWindow : Window {
 
-        public static readonly int RenewSec = 10;
-
-        protected AppDbContext Context { get; private set; }
         protected bool LockContext { get; set; } = false;
-
-        private readonly DispatcherTimer _timer;
         private bool _renewPending = false;
 
         public ContextWindow() : base() {
-            _timer = new DispatcherTimer();
-            _timer.Tick += new EventHandler(OnShouldRenewContext);
-            _timer.Interval = new TimeSpan(0, 0, RenewSec);
-            _timer.Start();
-            Context = new();
             Loaded += OnLoaded;
         }
 
@@ -30,22 +19,18 @@ namespace Elwig.Windows {
             await RenewContext();
         }
 
-        private async void OnShouldRenewContext(object? sender, EventArgs? evt) {
-            if (!Context.HasBackendChanged) return;
-            await HintContextChange();
-        }
-
         protected async void OnLoaded(object? sender, RoutedEventArgs? evt) {
-            await OnRenewContext();
+            using var ctx = new AppDbContext();
+            await OnRenewContext(ctx);
         }
 
         protected async Task RenewContext() {
             if (!_renewPending) return;
-            Context = new();
-            await OnRenewContext();
+            using var ctx = new AppDbContext();
+            await OnRenewContext(ctx);
             _renewPending = false;
         }
 
-        abstract protected Task OnRenewContext();
+        abstract protected Task OnRenewContext(AppDbContext ctx);
     }
 }