Add support for multi-dimensional arrays

src/Serilog/Capturing/PropertyValueConverter.cs

@@ -214,6 +214,29 @@ bool TryConvertEnumerable(object value, Type type, Destructuring destructuring,
                 {
                     result = SequenceValue.Empty;
                 }
+                else if (list is Array a && a.Rank > 1)
+                {
+                    int index = 0;
+                    var array = new LogEventPropertyValue[list.Count];
+                    if (a.Rank == 2)
+                    {
+                        for (int i = 0; i < a.GetLength(0); ++i)
+                            for (int j = 0; j < a.GetLength(1); ++j)
+                                array[index++] = _depthLimiter.CreatePropertyValue(a.GetValue(i, j), destructuring);
+                    }
+                    else if (a.Rank == 3)
+                    {
+                        for (int i = 0; i < a.GetLength(0); ++i)
+                            for (int j = 0; j < a.GetLength(1); ++j)
+                                for (int k = 0; k < a.GetLength(2); ++k)
+                                    array[index++] = _depthLimiter.CreatePropertyValue(a.GetValue(i, j, k), destructuring);
+                    }
+                    else
+                    {
+                        throw new NotSupportedException("Serilog does not support multi-dimensional arrays with Rank > 3.");
+                    }
+                    result = new SequenceValue(array);
+                }
                 else
                 {
                     var array = new LogEventPropertyValue[list.Count];

test/Serilog.Tests/Core/LoggerTests.cs

@@ -1,3 +1,4 @@
+using Shouldly;
 using System.Diagnostics;
 
 #pragma warning disable Serilog004 // Constant MessageTemplate verifier
@@ -317,6 +318,54 @@ public void NullMessageTemplateParametersDoNotBreakBinding()
         // ReSharper restore StructuredMessageTemplateProblem
     }
 
+    // https://github.com/serilog/serilog/issues/2019
+    [Fact]
+    public void Two_Dimensional_Array_Should_Be_Logger_As_Sequence()
+    {
+        var evt = DelegatingSink.GetLogEvent(l =>
+        {
+            var a = new object[3, 2] { { "a", "b" }, { "c", "d" }, { "e", "f" } };
+            l.Error("{@Value}", a);
+        });
+
+        evt.Properties.Count.ShouldBe(1);
+        var arr = evt.Properties["Value"].ShouldBeOfType<SequenceValue>();
+        arr.Elements.Count.ShouldBe(6);
+        arr.LiteralValue().ShouldBe("[a,b,c,d,e,f]");
+    }
+
+    // https://github.com/serilog/serilog/issues/2019
+    [Fact]
+    public void Three_Dimensional_Array_Should_Be_Logger_As_Sequence()
+    {
+        var evt = DelegatingSink.GetLogEvent(l =>
+        {
+            var a = new object[3, 2, 1] { { { "a" }, { "b" } }, { { "c" }, { "d" } }, { { "e" }, { "f" } } };
+            l.Error("{@Value}", a);
+        });
+
+        evt.Properties.Count.ShouldBe(1);
+        var arr = evt.Properties["Value"].ShouldBeOfType<SequenceValue>();
+        arr.Elements.Count.ShouldBe(6);
+        arr.LiteralValue().ShouldBe("[a,b,c,d,e,f]");
+    }
+
+
+    // https://github.com/serilog/serilog/issues/2019
+    [Fact]
+    public void Four_Dimensional_Array_Not_Supported()
+    {
+        var evt = DelegatingSink.GetLogEvent(l =>
+        {
+            var a = new object[4, 3, 2, 1];
+            l.Error("{@Value}", a);
+        });
+
+        evt.Properties.Count.ShouldBe(1);
+        var val = evt.Properties["Value"].ShouldBeOfType<ScalarValue>();
+        val.LiteralValue().ShouldBe("Capturing the property value threw an exception: NotSupportedException");
+    }
+
 #if FEATURE_ASYNCDISPOSABLE
 
     [Fact]

test/Serilog.Tests/Serilog.Tests.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <!-- Tests target .NET Framework 4.6.2 plus the latest RTM of .NET Framework -->
     <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT'">net462;net48</TargetFrameworks>
@@ -21,6 +21,7 @@
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" PrivateAssets="all" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
+    <PackageReference Include="Shouldly" Version="4.1.0" />
   </ItemGroup>
 
   <PropertyGroup Condition=" '$(TargetFramework)' == 'net462' ">

test/Serilog.Tests/Support/Extensions.cs

@@ -4,6 +4,11 @@ public static class Extensions
 {
     public static object? LiteralValue(this LogEventPropertyValue @this)
     {
-        return ((ScalarValue)@this).Value;
+        if (@this is ScalarValue scalar)
+            return scalar.Value;
+        else if (@this is SequenceValue sequence)
+            return $"[{string.Join(",", sequence.Elements.Select(e => e.LiteralValue()))}]";
+        else
+            throw new NotSupportedException(@this.GetType().Name);
     }
 }