ExceptionWithStatusAndMessageCode.cs

//
// COMMON DLL
//

public interface IStatusCode
{
	int? StatusCode { get; set; }
}

public static class IStatusCodeEx
{
	public static T WithStatusCode<T>(this T @this, int statusCode)
	  where T : Exception, IStatusCode
	{
		@this.StatusCode = statusCode;
		return @this;
	}
}

public interface IMessageCode
{
	string MessageCode { get; set; }
}

public static class IMessageCodeEx
{
	public static T WithMessageCode<T>(this T @this, object messageCode)
	  where T : Exception, IMessageCode
	{
		@this.MessageCode = messageCode?.ToString();
		return @this;
	}
}

public class BaseException : Exception, IMessageCode, IStatusCode
{
	public string MessageCode { get; set; }
	public int? StatusCode { get; set; }

	public BaseException() : base() {	}
	public BaseException(string message) : base (message)	{	}
	public BaseException(string message, Exception innerException) : base(message, innerException) { }
}
  
//
// WEB
//

public class ExceptionFilter : IExceptionFilter
{
	private ILogger logger;

	public ExceptionFilter(ILogger<ExceptionFilter> logger)
	{
		this.logger = logger;
	}

	public void OnException(Microsoft.AspNetCore.Mvc.Filters.ExceptionContext context)
	{
		logger.LogError(0, context.Exception, context.Exception.Message);

		var data = new ApiResult
		{
			StatusCode = (context.Exception as IStatusCode)?.StatusCode ?? (int) System.Net.HttpStatusCode.InternalServerError,

			Message = context.Exception.Message,
			MessageCode = (context.Exception as IMessageCode)?.MessageCode ?? "ERROR",

			ExceptionType = context.Exception.GetType().FullName,
			ExceptionDetails = context.Exception.ToString(),

			ModelValidationResult = context.ModelState?.ToCustomValidationResult()
		};

		// Generic result (so it can be xml or json)
		var result = new ObjectResult(data) { StatusCode = data.StatusCode };
		context.Result = result;
	}
}