关于完整解答Leo C.W博客中名为“我们公司的ASP.NET 笔试题，你觉得难度如何”的所有题目

    public enum QuestionType
    {
        Text = 0,
        MultipleChoice = 1
    }

    public interface IQuestion
    {
        string Title { get; set; }
        QuestionType Category { get; }

string GetAnswer();
    }

    public abstract class QuestionBase : IQuestion
    {
        public string Title { get; set; }
        public abstract QuestionType Category { get; }

        public virtual string GetAnswer()
        {
            return "默认答案";
        }

    }

    public class TextQuestion : QuestionBase
    {
        public override QuestionType Category { get { return QuestionType.Text; } }

        public override string GetAnswer()
        {
            return "文本答案";
        }
    }

    public class MultipleChoiceQuestion : QuestionBase
    {
        public override QuestionType Category { get { return QuestionType.MultipleChoice; } }

        public override string GetAnswer()
        {
            return "单选答案";
        }
    }

    public class Product
    {
        public string Name { get; set; }
        public string IsDeleted { get; set; }
    }

    public static class ProductExtension
    {
        public static IQueryable<Product> WhereNotDeleted(this IQueryable<Product> query)
        {
            return query.Where(p => p.IsDeleted != "是");
        }
    }

    public class ProductService
    {
        public List<Product> GetActiveProducts(IQueryable<Product> query)
        {
            return query.WhereNotDeleted().ToList();
        }
    }

select T1.Name,T2.[Year],T2.[Month],T2.InCome from [User] as T1 inner join
(select UserId,[Year],[Month],COUNT(Amount) AS InCome from InCome group by UserId,[Year],[Month]) as T2
on T1.Id=T2.UserId
order by T2.UserId,T2.[Year],T2.[Month]

select T1.Name,T2.[Year],T2.[Month],COUNT(T2.Amount) AS InCome from [User] as T1 
inner join InCome as T2 on T1.Id=T2.UserId
group by T1.Name,T2.[Year],T2.[Month] order by T1.Name,T2.[Year],T2.[Month]

    public class User
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }

    public class Income
    {
        public int Id { get; set; }
        public int UserId { get; set; }
        public decimal Amount { get; set; }
        public int Year { get; set; }
        public int Month { get; set; }
    }

    public class UserIncomeDto
    {
        public string Name { get; set; }
        public int Year { get; set; }
        public int Month { get; set; }
        public decimal Income { get; set; }
    }

    public class UserIncomeService
    {
        public List<UserIncomeDto> GetUserIncomeDtos(IQueryable<User> users, IQueryable<Income> incomes)
        {
            var resultList = (from u in users
                          join newic in
                              (from ic in incomes
                               group ic by new { ic.UserId, ic.Year, ic.Month } into gp
                               select new { gp.Key, InCome = gp.Sum(g => g.Amount) })
                              on u.Id equals newic.Key.UserId
                    orderby newic.Key
                    select new UserIncomeDto() { Name = u.Name, Year = newic.Key.Year, Month = newic.Key.Month, Income = newic.InCome }).ToList();

            return resultList;                             
        }
    }

<form action="/admin/mobile/user/login" method="POST">
    <input type="text" placeholder="username" name="username" />
    <input type="password" placeholder="password" name="password" />
    <input type="submit" value="login" />
</form>

            routes.MapRoute("UserLogin",
                            "~/admin/mobile/{controller}/{action}",
                            new { controller = "User", action = "Login" });

    public class Product1
    {
        public string Name { get; set; }
        public string Description { get; set; }

        public void Validate1()
        {
            if (string.IsNullOrEmpty(this.Name))
            {
                throw new Exception("please enter a name for the product");
            }
            if (string.IsNullOrEmpty(this.Description))
            {
                throw new Exception("product description is required");
            }
        }

        public void Validate2()
        {
            this.Require(x => x.Name, "please enter a name for the product");
            this.Require(x => x.Description, "product description is required");
        }

        public void Require(Expression<Func<Product1, string>> expression, string errorMessage)
        {
            Func<Product1, string> func = expression.Compile();

            if (string.IsNullOrEmpty(func(this)))
            {
                throw new Exception(errorMessage);
            }
        }
    }

    public class TestProgram
    {
        public static void Main()
        {
            Product1 product1 = new Product1();
            try
            {
                product1.Validate2();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            Console.Read();
        }
    }