Question

我有一个简单的实体模型

银行1 ---∞用户1 ---∞会话

在部分班级银行中，我必须在银行创建期间存储一个对象时钟设置。是否可以从Session方法中检索此Clock对象，当然，没有传递Bank参数？

一些代码

public partial class Bank : IBank { 私人IClock _bankClock;

    public IClock Clock
    {
        get { return _bankClock; }
        set { _bankClock = value; }
    }

}

public partial class Session : ISession public bool MyMethod() { var test = (dc.Session.Include("User.Bank").Where(t => t.session_id == session_id)); var temp = test.First().User.Bank.Clock.Now(); }

当调用MyMethod时，我得到的Object引用未设置为对象的实例。它被称为Clock属性。您是否有从LINQ查询中检索自定义对象的任何提示？

谢谢你，最诚挚的问候

更多代码 // CreateBank

public IBank CreateBank(string bankName, int valuePassedInCreateMethod, Clock bankClock) {using (var dc = new Database1Entities(Functions.ToEntitiesConnectionString(connectionString))) { _dbField=valuePassedInCreateMethod; bankReturn=(from c in dc.Bank where c.bank_name == bankName select c).First(); bankReturn.Clock = bankClock; dc.SaveChanges(); return bankReturn;

}

Answer 1

检查对象创建_bankClock，你为它分配了一些值吗？

看我是否接近你的要求。我得到了这个工作

   static class Program
{
    [STAThread]
    static void Main()
    {
        User user = new User();
        user.Bank = Bank.CreateBank("my bank", 23, new Clock());
        Session session = new Session(user, "myid");
        bool returned = session.MyMethod();
        if (returned)
            MessageBox.Show("Got it");
    }

}

public class Bank
{

    int value;
    string bankName;
    public Clock Clock;

    public static Bank CreateBank(string bankName, int valuePassedInCreateMethod, Clock bankClock)
    {
        Bank b = new Bank();
        b.Clock = bankClock;
        b.bankName = bankName;
        b.value = valuePassedInCreateMethod;
        return b;
    }
}

public class User
{
    public Bank Bank;
    public string type = "User.Bank";
}

public partial class Session
{

    public static List<Session> Sessions;
    string type;
    string session_id;
    User User;

    public Session(User user, string session_id)
    {
        if (Sessions == null) Sessions = new List<Session>();
        this.User = user;
        this.type = user.type;
        this.session_id = session_id;
        Sessions.Add(this);
    }

    static void Add(Session session)
    {
        Sessions.Add(session);
    }
    static List<Session> Include(string type)
    {
        return Sessions.Where(rs => rs.type == type).ToList<Session>();
    }
    public bool MyMethod()
    {
        var test = Session.Include("User.Bank");
        var test1 = test.Where(t => t.session_id == session_id);
        var temp = test1.First();
        var temp1 = temp.User;
        var temp2 = temp1.Bank;
        var temp3 = temp2.Clock;
        var temp4 = temp3.Now();
        if (temp4 != DateTime.MinValue)
            return true;
        return false;
    }
}
public class Clock
{
    public DateTime Now()
    {
        return DateTime.Now;
    }
}

c＃LINQ to Entities：检索自定义对象

1 个答案: