added stringification support

Author: bicj-leica

src/Serilog.Extensions.Logging/Extensions/Logging/SerilogLogger.cs

@@ -78,6 +78,11 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Except
                         if (logger.BindProperty(property.Key.Substring(1), property.Value, true, out var destructured))
                             properties.Add(destructured);
                     }
+                    else if (property.Key.StartsWith("$"))
+                    {
+                        if (logger.BindProperty(property.Key.Substring(1), property.Value?.ToString() ?? "null", true, out var stringified))
+                            properties.Add(stringified);
+                    }
                     else
                     {
                         if (logger.BindProperty(property.Key, property.Value, false, out var bound))

test/Serilog.Extensions.Logging.Tests/SerilogLoggerTests.cs

@@ -219,6 +219,24 @@ public void CarriesMessageTemplateProperties()
             Assert.Empty(selfLog.ToString());
         }
 
+        [Fact]
+        public void CarriesMessageTemplatePropertiesWhenStringificationIsUsed()
+        {
+            var selfLog = new StringWriter();
+            SelfLog.Enable(selfLog);
+            var (logger, sink) = SetUp(LogLevel.Trace);
+            var array = new[] { 1, 2, 3, 4 };
+
+            logger.LogInformation("{$array}", array);
+
+            Assert.True(sink.Writes[0].Properties.ContainsKey("array"));
+            Assert.Equal("\"System.Int32[]\"", sink.Writes[0].Properties["array"].ToString());
+            Assert.Equal("{$array}", sink.Writes[0].MessageTemplate.Text);
+
+            SelfLog.Disable();
+            Assert.Empty(selfLog.ToString());
+        }
+
         [Fact]
         public void CarriesEventIdIfNonzero()
         {