Projektdateien hinzufügen.

WindowsFormsApp1/OP/Subject.cs

@@ -0,0 +1,43 @@
+using System.Collections.Generic;
+
+namespace WindowsFormsApp1.OP
+{
+    /// <summary>
+    /// Owns some important state and notifies observers when the state changes.
+    /// </summary>
+    public class Subject<T> : ISubject<T>
+    { 
+        private protected List<IObserver<T>> _observers = null;
+        private object state { get;set; }
+
+        public Subject()
+        {
+            _observers = new List<IObserver<T>>();
+        }
+
+        public virtual void Subscribe(IObserver<T> observer)
+        {
+            _observers.Add(observer);
+        }
+        public virtual void Unsubscribe(IObserver<T> observer)
+        {
+            _observers.Remove(observer);
+        }
+        public void Notify()
+        {
+            foreach (IObserver<T> observer in _observers)
+            {
+                observer.Update(this);
+            }
+        }
+        public virtual void SetState(T state)
+        {
+            this.state = state;
+            Notify();
+        }
+        public virtual T GetState()
+        {
+            return (T)state;
+        }
+    }
+}