diff --git a/dotnet/src/dotnetframework/GxClasses/Services/ReflectionHelper.cs b/dotnet/src/dotnetframework/GxClasses/Services/ReflectionHelper.cs
index 9decf8f22..b7dde1720 100644
--- a/dotnet/src/dotnetframework/GxClasses/Services/ReflectionHelper.cs
+++ b/dotnet/src/dotnetframework/GxClasses/Services/ReflectionHelper.cs
@@ -237,8 +237,15 @@ internal static object[] ProcessParametersForInvoke(MethodInfo methodInfo, IDict
 				}
 				if (parameters!=null && parameters.TryGetValue(gxParameterName, out value))
 				{
-					var convertedValue = ConvertStringToNewType(value, parmType, context);
-					parametersForInvocation[idx] = convertedValue;
+					if (value == null || JSONHelper.IsJsonNull(value))
+					{
+						parametersForInvocation[idx] = null;
+					}
+					else
+					{
+						var convertedValue = ConvertStringToNewType(value, parmType, context);
+						parametersForInvocation[idx] = convertedValue;
+					}
 				}
 				else
 				{