add support for non-void event delegates (#418)

microsoft · Sep 22, 2020 · 224ee35 · 224ee35
1 parent 290e744
commit 224ee35
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Showing 5 changed files with 34 additions and 2 deletions.
diff --git a/TestComponentCSharp/Class.cpp b/TestComponentCSharp/Class.cpp
@@ -265,6 +265,19 @@ namespace winrt::TestComponentCSharp::implementation
  {
  _nestedTypedEvent(sender, arg0);
  }
+ winrt::event_token Class::ReturnEvent(TestComponentCSharp::EventWithReturn const& handler)
+ {
+ return _returnEvent.add(handler);
+ }
+ void Class::ReturnEvent(winrt::event_token const& token) noexcept
+ {
+ _returnEvent.remove(token);
+ }
+ int32_t Class::InvokeReturnEvent(int32_t const& arg0)
+ {
+ _returnEvent(arg0);
+ return arg0;
+ }
  int32_t Class::IntProperty()
  {
  return _int;

diff --git a/TestComponentCSharp/Class.h b/TestComponentCSharp/Class.h
@@ -16,6 +16,7 @@ namespace winrt::TestComponentCSharp::implementation
  winrt::event<EventHandlerCollection> _collectionEvent;
  winrt::event<Windows::Foundation::EventHandler<Windows::Foundation::Collections::IVector<int32_t>>> _nestedEvent;
  winrt::event<Windows::Foundation::TypedEventHandler<TestComponentCSharp::Class, Windows::Foundation::Collections::IVector<hstring>>> _nestedTypedEvent;
+ winrt::event<TestComponentCSharp::EventWithReturn> _returnEvent;
 
  int32_t _int = 0;
  winrt::event<Windows::Foundation::EventHandler<int32_t>> _intChanged;
@@ -106,6 +107,10 @@ namespace winrt::TestComponentCSharp::implementation
  winrt::event_token NestedTypedEvent(Windows::Foundation::TypedEventHandler<TestComponentCSharp::Class, Windows::Foundation::Collections::IVector<hstring>> const& handler);
  void NestedTypedEvent(winrt::event_token const& token) noexcept;
  void InvokeNestedTypedEvent(TestComponentCSharp::Class const& sender, Windows::Foundation::Collections::IVector<hstring> const& arg0);
+ winrt::event_token ReturnEvent(TestComponentCSharp::EventWithReturn const& handler);
+ void ReturnEvent(winrt::event_token const& token) noexcept;
+ int32_t InvokeReturnEvent(int32_t const& arg0);
+
  int32_t IntProperty();
  void IntProperty(int32_t value);
  winrt::event_token IntPropertyChanged(Windows::Foundation::EventHandler<int32_t> const& handler);

diff --git a/TestComponentCSharp/TestComponentCSharp.idl b/TestComponentCSharp/TestComponentCSharp.idl
@@ -11,6 +11,7 @@ namespace TestComponentCSharp
  delegate void EventHandler2(Class sender, Int32 arg0);
  delegate void EventHandler3(Class sender, Int32 arg0, String arg1);
  delegate void EventHandlerCollection(Class sender, Windows.Foundation.Collections.IVector<Int32> arg0, Windows.Foundation.Collections.IMap<Int32, String> arg1);
+ delegate Int32 EventWithReturn(Int32 arg);
 
  struct BlittableStruct
  {
@@ -135,6 +136,8 @@ namespace TestComponentCSharp
  void InvokeNestedEvent(Class sender, Windows.Foundation.Collections.IVector<Int32> arg0);
  event Windows.Foundation.TypedEventHandler<Class, Windows.Foundation.Collections.IVector<String> > NestedTypedEvent;
  void InvokeNestedTypedEvent(Class sender, Windows.Foundation.Collections.IVector<String> arg0);
+ event EventWithReturn ReturnEvent;
+ Int32 InvokeReturnEvent(Int32 arg0);
 
  Int32 IntProperty;
  event Windows.Foundation.EventHandler<Int32> IntPropertyChanged;

diff --git a/UnitTest/TestComponentCSharp_Tests.cs b/UnitTest/TestComponentCSharp_Tests.cs
@@ -130,6 +130,14 @@ public void TestEvents()
  TestObject.InvokeNestedEvent(TestObject, ints);
  events_expected++;
 
+ TestObject.ReturnEvent += (int arg0) =>
+ {
+ events_received++;
+ return arg0;
+ };
+ Assert.Equal(42, TestObject.InvokeReturnEvent(42));
+ events_expected++;
+
  var collection0 = new int[] { 42, 1729 };
  var collection1 = new Dictionary<int, string> { [1] = "foo", [2] = "bar" };
  TestObject.CollectionEvent += (Class sender, IList<int> arg0, IDictionary<int, string> arg1) =>

diff --git a/cswinrt/strings/WinRT.cs b/cswinrt/strings/WinRT.cs
@@ -409,10 +409,13 @@ private System.Delegate EventInvoke
 
  _eventInvoke = Expression.Lambda(typeof(TDelegate),
  Expression.Block(
+ invoke.ReturnType,
  new[] { delegateLocal },
  Expression.Assign(delegateLocal, Expression.Field(Expression.Constant(this), typeof(EventSource<TDelegate>).GetField(nameof(_event), BindingFlags.Instance | BindingFlags.NonPublic))),
- Expression.IfThen(
- Expression.ReferenceNotEqual(delegateLocal, Expression.Constant(null, typeof(TDelegate))), Expression.Call(delegateLocal, invoke, parameters))),
+ Expression.Condition(
+ Expression.ReferenceNotEqual(delegateLocal, Expression.Constant(null, typeof(TDelegate))),
+ Expression.Call(delegateLocal, invoke, parameters),
+ Expression.Default(invoke.ReturnType))),
  parameters).Compile();
 
  return _eventInvoke;