fix #291 - CreateChangedEventCodeRefactoringProvider exception on aut…

…o-implemented property (VB)

RefactoringEssentials/VB/CodeRefactorings/CreateChangedEventCodeRefactoringProvider.cs

@@ -35,6 +35,9 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
 
             var propertyBlock = property.Parent as PropertyBlockSyntax;
 
+			if (propertyBlock == null)
+				return;
+
             var field = GetBackingField(model, propertyBlock);
             if (field == null)
                 return;

Tests/VB/CodeRefactorings/CreateChangedEventTests.cs

@@ -214,6 +214,17 @@ End Set
     End Property
 End Class");
         }
-    }
+
+		[Fact]
+		public void TestIssue291()
+		{
+			TestWrongContext<CreateChangedEventCodeRefactoringProvider>(@"
+Class TestClass
+    Dim _test As String
+
+    Public Property $Test As String
+End Class");
+		}
+	}
 }