faster delete the sessions from wpf sample app

Author: honfika

examples/Titanium.Web.Proxy.Examples.Wpf/MainWindow.xaml.cs

@@ -101,7 +101,7 @@ public MainWindow()
             InitializeComponent();
         }
 
-        public ObservableCollection<SessionListItem> Sessions { get; } = new ObservableCollection<SessionListItem>();
+        public ObservableCollectionEx<SessionListItem> Sessions { get; } = new ObservableCollectionEx<SessionListItem>();
 
         public SessionListItem SelectedSession
         {
@@ -280,11 +280,14 @@ private void ListViewSessions_OnKeyDown(object sender, KeyEventArgs e)
             if (e.Key == Key.Delete)
             {
                 var selectedItems = ((ListView)sender).SelectedItems;
+                Sessions.SuppressNotification = true;
                 foreach (var item in selectedItems.Cast<SessionListItem>().ToArray())
                 {
                     Sessions.Remove(item);
                     sessionDictionary.Remove(item.HttpClient);
                 }
+
+                Sessions.SuppressNotification = false;
             }
         }
 

examples/Titanium.Web.Proxy.Examples.Wpf/ObservableCollectionEx.cs

@@ -0,0 +1,36 @@
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+
+namespace Titanium.Web.Proxy.Examples.Wpf
+{
+    public class ObservableCollectionEx<T> : ObservableCollection<T>
+    {
+        private bool notificationSuppressed;
+        private bool suppressNotification;
+
+        public bool SuppressNotification
+        {
+            get => suppressNotification;
+            set
+            {
+                suppressNotification = value;
+                if (suppressNotification == false && notificationSuppressed)
+                {
+                    OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
+                    notificationSuppressed = false;
+                }
+            }
+        }
+
+        protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
+        {
+            if (SuppressNotification)
+            {
+                notificationSuppressed = true;
+                return;
+            }
+
+            base.OnCollectionChanged(e);
+        }
+    }
+}