Merge pull request #2868 from PrismLibrary/ea-current

EA add static instance

.github/workflows/build_core.yml

@@ -12,6 +12,7 @@ on:
       - Directory.Packages.props
       - xunit.runner.json
       - 'src/Prism.Core/**'
+      - 'src/Prism.Events/**'
       - 'tests/Prism.Core.Tests/**'
 
 jobs:

.github/workflows/build_forms.yml

@@ -12,6 +12,7 @@ on:
       - Directory.Packages.props
       - xunit.runner.json
       - 'src/Prism.Core/**'
+      - 'src/Prism.Events/**'
       - 'tests/Prism.Core.Tests/**'
       - 'src/Forms/**'
       - 'tests/Forms/**'

.github/workflows/build_maui.yml

@@ -12,6 +12,7 @@ on:
       - Directory.Packages.props
       - xunit.runner.json
       - 'src/Prism.Core/**'
+      - 'src/Prism.Events/**'
       - 'tests/Prism.Core.Tests/**'
       - 'src/Maui/**'
       - 'tests/Containers/**'

.github/workflows/build_uno.yml

@@ -12,6 +12,7 @@ on:
       - Directory.Packages.props
       - xunit.runner.json
       - 'src/Prism.Core/**'
+      - 'src/Prism.Events/**'
       - 'tests/Prism.Core.Tests/**'
       - 'src/Wpf/**'
       - 'tests/Wpf/**'

.github/workflows/build_wpf.yml

@@ -12,6 +12,7 @@ on:
       - Directory.Packages.props
       - xunit.runner.json
       - 'src/Prism.Core/**'
+      - 'src/Prism.Events/**'
       - 'tests/Prism.Core.Tests/**'
       - 'src/Wpf/**'
       - 'tests/Wpf/**'

src/Prism.Events/EventAggregator.cs

-
-
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Threading;
 
 namespace Prism.Events
@@ -11,8 +10,30 @@ namespace Prism.Events
     /// </summary>
     public class EventAggregator : IEventAggregator
     {
+        private static IEventAggregator _current;
+
+        /// <summary>
+        /// Gets or Sets the Current Instance of the <see cref="IEventAggregator"/>
+        /// </summary>
+        public static IEventAggregator Current
+        {
+            get => _current ??= new EventAggregator();
+            set => _current = value;
+        }
+
+        /// <summary>
+        /// Creates a new instance of the <see cref="EventAggregator"/>
+        /// </summary>
+        public EventAggregator()
+        {
+            if(_current is null)
+            {
+                _current = this;
+            }
+        }
+
         private readonly Dictionary<Type, EventBase> events = new Dictionary<Type, EventBase>();
-        // Captures the sync context for the UI thread when constructed on the UI thread 
+        // Captures the sync context for the UI thread when constructed on the UI thread
         // in a platform agnostic way so it can be used for UI thread dispatching
         private readonly SynchronizationContext syncContext = SynchronizationContext.Current;