EncapsulatedResult.cs

public class Result<T>
{
    public bool IsSuccess { get; private set; }
    public string ErrorMessage { get; private set; }
    public IEnumerable<T> Results { get; private set; }

    private Result()
    { }

    public static Result<T> Success(IEnumerable<T> results)
    {
        return new Result<T>
        {
            IsSuccess = true,
            Results = results
        };
    }

    public static Result<T> Success(T result)
    {
        return Success(new[] { result });
    }

    public static Result<T> Error(int statusCode, string reasonPhrase)
    {
        return new Result<T>
        {
            ErrorMessage = string.Format("Error {0}: {1}", statusCode, reasonPhrase),
            Results = Enumerable.Empty<T>()
        };
    }
}