Add search input delay of 200ms

Elwig/Windows/AdministrationWindow.cs

@@ -7,6 +7,7 @@ using System.Linq;
 using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Controls;
+using System.Windows.Threading;
 using Xceed.Wpf.Toolkit;
 
 namespace Elwig.Windows {
@@ -225,6 +226,22 @@ namespace Elwig.Windows {
             UpdateComboBox(ortInput);
         }
 
+        protected static void InitializeDelayTimer(TextBox tb, Action<object, TextChangedEventArgs> handler) {
+            var timer = new DispatcherTimer {
+                Interval = TimeSpan.FromMilliseconds(250)
+            };
+            timer.Tick += (object? sender, EventArgs evt) => {
+                timer.Stop();
+                var (oSender, oEvent) = ((object, TextChangedEventArgs))timer.Tag;
+                handler(oSender, oEvent);
+            };
+            tb.TextChanged += (object sender, TextChangedEventArgs evt) => {
+                timer.Stop();
+                timer.Tag = (sender, evt);
+                timer.Start();
+            };
+        }
+
         protected bool InputTextChanged(TextBox input, Func<TextBox, bool, ValidationResult> checker) {
             return InputTextChanged(input, (tb, required, ctx) => checker(tb, required));
         }