group and subgroup adding/editing, services added

TimetableDesigner.Customs/ObservableDictionary.cs

@@ -7,7 +7,7 @@ using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 
-namespace TimetableDesigner.Customs.Collections
+namespace TimetableDesigner.Customs
 {
     public class ObservableDictionary<TKey, TValue> : ObservableCollection<ObservableKeyValuePair<TKey, TValue>>, IDictionary<TKey, TValue>
     {
@@ -59,7 +59,7 @@ namespace TimetableDesigner.Customs.Collections
         {
             foreach (KeyValuePair<TKey, TValue> pair in dictionary)
             {
-                this.Add(pair);
+                Add(pair);
             }
         }
 

TimetableDesigner.Customs/ObservableKeyValuePair.cs

@@ -5,7 +5,7 @@ using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 
-namespace TimetableDesigner.Customs.Collections
+namespace TimetableDesigner.Customs
 {
     public class ObservableKeyValuePair<TKey, TValue> : INotifyPropertyChanged
     {

TimetableDesigner.Customs/ObservableObject.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace TimetableDesigner.Customs
+{
+    public class ObservableObject : INotifyPropertyChanged
+    {
+        #region PRIVATE METHODS
+
+        protected void NotifyPropertyChanged(string propertyName) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+
+        #endregion
+
+
+
+        #region EVENTS
+
+        public event PropertyChangedEventHandler? PropertyChanged;
+
+        #endregion
+    }
+}