App: Do not use FileSystemWatcher any more

Elwig/App.xaml.cs

@@ -60,10 +60,9 @@ namespace Elwig {
         public static ClientParameters Client { get; set; }
 
         public static Dispatcher MainDispatcher { get; private set; }
-        private readonly FileSystemWatcher Watcher = new(Path.GetDirectoryName(Config.DatabaseFile) ?? "C:\\") {
-            NotifyFilter = NotifyFilters.LastWrite,
-            Filter = "*.sqlite3",
-        };
+        private DateTime LastChanged;
+        private static DateTime CurrentLastWrite => File.GetLastWriteTime(Config.DatabaseFile);
+        private readonly DispatcherTimer ContextTimer = new() { Interval = TimeSpan.FromSeconds(2) };
 
         public App() : base() {
             System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);
@@ -73,11 +72,16 @@ namespace Elwig {
             Scales = [];
             CurrentApp = this;
             OverrideCulture();
-            Watcher.Changed += new FileSystemEventHandler(OnChanged);
-            Watcher.EnableRaisingEvents = true;
+
+            ContextTimer.Tick += (object? sender, EventArgs evt) => {
+                if (CurrentLastWrite > LastChanged) {
+                    LastChanged = CurrentLastWrite;
+                    OnContextChanged();
+                }
+            };
         }
 
-        private void OnChanged(object source, FileSystemEventArgs e) {
+        private static void OnContextChanged() {
             MainDispatcher.BeginInvoke(async () => await HintContextChange());
         }
 
@@ -112,6 +116,9 @@ namespace Elwig {
                 return;
             }
 
+            LastChanged = CurrentLastWrite;
+            ContextTimer.Start();
+
             Dictionary<string, (string, string, int?, string?, string?, string?, string?, string?)> branches = [];
             using (var ctx = new AppDbContext()) {
                 branches = ctx.Branches.ToDictionary(b => b.Name.ToLower(), b => (b.ZwstId, b.Name, b.PostalDest?.AtPlz?.Plz, b.PostalDest?.AtPlz?.Ort.Name, b.Address, b.PhoneNr, b.FaxNr, b.MobileNr));
@@ -193,6 +200,7 @@ namespace Elwig {
         }
 
         public static async Task HintContextChange() {
+            CurrentApp.LastChanged = CurrentLastWrite;
             foreach (Window w in CurrentApp.Windows) {
                 if (w is not ContextWindow c) continue;
                 await c.HintContextChange();

Elwig/Windows/ContextWindow.cs

@@ -1,5 +1,4 @@
 using Elwig.Helpers;
-using System;
 using System.Threading.Tasks;
 using System.Windows;