Sandbox test for instance ref handling

src/net/Qt.NetCore.Sandbox/Program.UI.cs

@@ -25,6 +25,43 @@ namespace Qt.NetCore.Sandbox
         {
             
         }
+
+        public class InstanceType
+        {
+            public InstanceType()
+            {
+
+            }
+        }
+
+        public class TestQmlInstanceHandling
+        {
+            private InstanceType _instanceType;
+            private WeakReference<InstanceType> _weakInstanceTypeRef;
+
+            public int State { get; set; } = 0;
+
+            public TestQmlInstanceHandling()
+            {
+                _instanceType = new InstanceType();
+                _weakInstanceTypeRef = new WeakReference<InstanceType>(_instanceType);
+            }
+
+            public InstanceType GetInstance()
+            {
+                return _instanceType;
+            }
+
+            public void DeleteInstances()
+            {
+                _instanceType = null;
+            }
+
+            public bool IsInstanceAlive()
+            {
+                return _weakInstanceTypeRef.TryGetTarget(out var _);
+            }
+        }
         
         static int Main()
         {
@@ -43,7 +80,8 @@ namespace Qt.NetCore.Sandbox
                     var type = NetTypeManager.GetTypeInfo<TestQmlImport>();
                     
                     QQmlApplicationEngine.RegisterType<TestQmlImport>("test");
-                    
+                    QQmlApplicationEngine.RegisterType<TestQmlInstanceHandling>("testInstances");
+
                     engine.Load("main.qml");
 
                     return app.Exec();

src/net/Qt.NetCore.Sandbox/main.qml

@@ -2,6 +2,7 @@ import QtQuick 2.7
 import QtQuick.Controls 2.0
 import QtQuick.Layouts 1.0
 import test 1.0
+import testInstances 1.0
 
 ApplicationWindow {
     visible: true
@@ -20,9 +21,38 @@ ApplicationWindow {
                 o2.testSignal("Hello")
 			}
 		}
+		Timer {
+		    id: instanceCheckTimer
+			interval: 1000; running: true; repeat: true
+			onTriggered: {
+				if(testInstances.State == 0) {
+					var ref1 = testInstances.GetInstance()
+					var ref2 = testInstances.GetInstance()
+
+					ref1 = null
+					ref2 = null
+					
+					console.log("Created and deleted two references on QML side. IsAlive = " + testInstances.IsInstanceAlive())
+					testInstances.State = 1
+				} else if(testInstances.State == 1) {
+					testInstances.DeleteInstances()
+					console.log("Deleting .Net references. IsAlive = " + testInstances.IsInstanceAlive())
+					testInstances.State = 2
+				} else if(testInstances.State == 2) {
+					if(testInstances.IsInstanceAlive()) {
+						console.log("Yeah! Instance has been released!");
+						instanceCheckTimer.running = false
+					}
+				}
+			}
+		}
 	}
 
 	TestQmlImport {
 		id: test
 	}
+
+	TestQmlInstanceHandling {
+		id: testInstances
+	}
 }