Question

我的项目中有两个虚拟存储库，一个用于问题，一个用于答案。问题是多重选择，因此他们可以有多个答案。我的问题模型：

public class Question : BaseClass
{
    public Question() : base()
    {

    }

    public int QuestionId { get; set; }
    public string Value { get; set; }

    public virtual List<Answer> Answers { get; set; }
}

答案属于问题

public class Answer : BaseClass
{
    public Answer() : base()
    {

    }
    public int AnswerId { get; set; }
    public string Value { get; set; }

    public int QuestionId { get; set; }
    public virtual Question Question { get; set; } 
}

它们都扩展了 BaseClass ，它有一些自定义字段。

public abstract class BaseClass
{
    protected BaseClass()
    {
        UniqueIdentifier = RandomIdentifier(20);
    }

    public string UniqueIdentifier { get; set; }

    private static string RandomIdentifier(int length)
    {
     //returns an unique identifier 
    }
}

我的 dummyQuestionRepository 如下所示：

public class DummyQuestionRepository : IQuestionRepository
{

    private  List<Question> _questions;

    public DummyQuestionRepository()
    {
        _questions = new List<Question>();
        _questions.Add(new Question { Value = "Favourit food?" });
        _questions.Add(new Question { Value = "Who is the president?" });
        _questions.Add(new Question { Value = "Favourit movie?" });
    }

    public List<Question> GetAll()
    {
        return _questions;
    }
    public void Create(Question q)
    {
        _questions.Add(q);
    }

   //removed the non relevant functions
}

我的 dummyAnswerRepository

class DummyAnswerRepository
{
    private  List<Answer> _answers;

    public DummyAnswerRepository()
    {
        _answers = new List<Answer>();
        _answers.Add(new Answer { Value = "pizza" });
        _answers.Add(new Answer { Value = "fries" });
        _answers.Add(new Answer { Value = "Bush" });
        _answers.Add(new Answer { Value = "Obama" });
        _answers.Add(new Answer { Value = "titanic" });
        _answers.Add(new Answer { Value = "lion king" });
    }

   public List<Answer> GetAll()
    {
        return _answers;
    }

    public void Create(Answer a)
    {
        _answers.Add(a);

    }
}

您可能会注意到baseclass有一个UniqueIdentifier变量。此变量用于在联机数据库中创建唯一值（因为用户可以在脱机工作时使用相同的ID，因此无法使用id），答案应将UniqueIdentifier作为外键。我应该如何从问题中获取/设置答案，以便我可以在我的视图中加载它们？

Answer 1

好方法是使用Guid来帮助您合并用户数据库，因为Guid有2 ^ 128个唯一值。使用Guid.NewGuid生成新的唯一值

public abstract class BaseClass
{
    protected BaseClass()
    {
        UniqueIdentifier = Guid.NewGuid();
    }

    public Guid UniqueIdentifier { get; set; }
}

要添加外键，当答案和问题在一个位置创建然后添加到您的存储库时，您可以实现类似于Entity Framework Seed method的方法。只需删除从存储库构造函数创建新实体的代码，并使用如下代码：

public class DataBaseInitializer
{
    public void Seed(IQuestionRepository questionRepository, DummyAnswerRepository answerRepository)
    {
        var q1 = new Question { Value = "Favourit food?" };
        var q2 = new Question { Value = "Who is the president?" });
        var q3 = new Question { Value = "Favourit movie?" });

        questionRepository.Create(q1);
        questionRepository.Create(q2);
        questionRepository.Create(q3);

        answerRepository.Create(new Answer { Value = "pizza", Question = q1 });
        answerRepository.Create(new Answer { Value = "fries", Question = q1 });
        answerRepository.Create(new Answer { Value = "Bush", Question = q2 });
        answerRepository.Create(new Answer { Value = "Obama", Question = q2 });
        answerRepository.Create(new Answer { Value = "titanic", Question = q3 });
        answerRepository.Create(new Answer { Value = "lion king", Question = q3 });
    }
}

dummyrepository数据具有随机ID

1 个答案: