VB -> C#: Convert use of event backing field - fixes #186

Author: GrahamTheCoder

ICSharpCode.CodeConverter/CSharp/CommonConversions.cs

@@ -286,8 +286,10 @@ public SyntaxToken ConvertIdentifier(SyntaxToken id, bool isAttribute = false)
                         // The case above is basically that if the symbol is a parameter, and the corresponding definition is a property set definition 
                         // AND the first explicitly declared parameter is this symbol, we need to replace it with value.
                         text = "value";
-                    } else if (text.StartsWith("_", StringComparison.OrdinalIgnoreCase) && symbol is IFieldSymbol fieldSymbol && fieldSymbol.AssociatedSymbol?.IsKind(SymbolKind.Property) == true) {
-                        text = fieldSymbol.AssociatedSymbol.Name;
+                    } else if (text.StartsWith("_", StringComparison.OrdinalIgnoreCase) && symbol is IFieldSymbol propertyFieldSymbol && propertyFieldSymbol.AssociatedSymbol?.IsKind(SymbolKind.Property) == true) {
+                        text = propertyFieldSymbol.AssociatedSymbol.Name;
+                    } else if (text.EndsWith("Event", StringComparison.OrdinalIgnoreCase) && symbol is IFieldSymbol eventFieldSymbol && eventFieldSymbol.AssociatedSymbol?.IsKind(SymbolKind.Event) == true) {
+                        text = eventFieldSymbol.AssociatedSymbol.Name;
                     }
                 }
             }

Tests/CSharp/ExpressionTests.cs

@@ -997,6 +997,37 @@ public void Tuple()
 }");
         }
 
+        [Fact]
+        public void UseEventBackingField()
+        {
+            TestConversionVisualBasicToCSharpWithoutComments(
+                @"Public Class Foo
+    Public Event Bar As EventHandler(Of EventArgs)
+
+    Protected Sub OnBar(e As EventArgs)
+        If BarEvent Is Nothing Then
+            System.Diagnostics.Debug.WriteLine(""No subscriber"")
+        Else
+            RaiseEvent Bar(Me, e)
+        End If
+    End Sub
+End Class",
+                @"using System;
+
+public class Foo
+{
+    public event EventHandler<EventArgs> Bar;
+
+    protected void OnBar(EventArgs e)
+    {
+        if (Bar == null)
+            System.Diagnostics.Debug.WriteLine(""No subscriber"");
+        else
+            Bar?.Invoke(this, e);
+    }
+}");
+        }
+
         [Fact]
         public void StringInterpolationWithDoubleQuotes()
         {