实体框架System.InvalidOperationException [英] Entity Framework System.InvalidOperationException

问题描述

我在2个不同的类中使用实体框架容器。私有静态DataManager实例;

  
 private Model1Container databaseContainer; 
 private DataManager（）
 {
 databaseContainer = new Model1Container（）; 
} 
 
 public static IDataManager Instance 
 {
 get 
 {
 if（instance == null）
 {
 instance = new DataManager（）; 
} 
 return instance; 
} 
} 
 
 public void OpenNewAccount（int amount）
 {
 
帐户帐户=新帐户（）; 
 
事务事务=新事务（）; 
 transaction.Account = account; 
 transaction.Amount = amount; 
 transaction.Date = DateTime.Now; 
 
 if（TransactionExecutor.Instance.ExecuteTransaction（transaction，account））
 {
 // EXCEPTION System.Data.Entity中出现类型为System.InvalidOperationException的未处理异常.dll 
 
 //附加信息：实体对象不能被IEntityChangeTracker的多个实例引用。 
 databaseContainer.Transactions.AddObject（transaction）; 
 databaseContainer.Accounts.AddObject（account）; 
 databaseContainer.SaveChanges（）; 
} 
} 
 
 class AccountStateTransactionValidator：AbstractTransactionValidator 
 {
 override 
 public bool HandleTransaction（Transaction transaction，Account account）
 {
 if（account.AccountState == null ||（account.Amount< account.AccountState.LeftBound || account.Amount> = account.AccountState.RightBound））
 {
 Model1Container container = new Model1Container（）; 
 AccountState properState =（from st in container.AccountStates 
 where st.LeftBound< = account.Amount&& 
 st.RightBound> = account.Amount 
 select ST）.FirstOrDefault（）; 
 if（properState！= null）
 {
 account.AccountState = properState; 
} 
 else 
 {
 return false; 
} 
} 
 
 return base.nextTransaction（transaction，account）; 
 
} 
} 
  

我得到这个异常： / p>

 在System.AppDomain._nExecuteAssembly（RuntimeAssembly assembly，String [] args）
在System.AppDomain.ExecuteAssembly（String assemblyFile，Evidence assemblySecurity，String [] args）
在Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly（）
在System.Threading.ThreadHelper.ThreadStart_Context（对象状态）
在System.Threading .executionContext.Run（ExecutionContext executionContext，ContextCallback callback，Object state，Boolean ignoreSyncCtx）
在System.Threading.ExecutionContext.Run（ExecutionContext executionContext，ContextCallback callback，Object state）
在System.Threading.ThreadHelper。的ThreadStart（）< / ExceptionString>< /异常>< / TraceRecord> 
 System.Data.Entity.dll中发生类型为System.InvalidOperationException的未处理的异常
  

我不想修改我的类结构，在这种情况下可以正确使用Entity Framework吗？如何？

感谢您的答案。

解决方案

混合多个数据上下文：帐户附加到 databaseContainer （ databaseContainer.Transactions.AddObject（transaction ）; 与帐户作为来自 transaction 的嵌套属性），但来自 Model1Container container = new Model1Container（）; 。

您不能在同一个上下文中使用实体实例时间。

---

另外，我看到一种数据容器的单例模式，这通常是坏的，坏的，坏的想法...

I use entity framework container within 2 different classes.

private static DataManager instance;
    private Model1Container databaseContainer;
    private DataManager()
    {
        databaseContainer = new Model1Container();
    }

    public static IDataManager Instance
    {
        get
        {
            if (instance == null)
            {
                instance = new DataManager();
            }
            return instance;
        }
    }

    public void OpenNewAccount(int amount)
    {

        Account account = new Account();

        Transaction transaction = new Transaction();
        transaction.Account = account;
        transaction.Amount = amount;
        transaction.Date = DateTime.Now;

        if (TransactionExecutor.Instance.ExecuteTransaction(transaction, account))
        {
            //EXCEPTION An unhandled exception of type                   'System.InvalidOperationException' occurred in System.Data.Entity.dll

            //Additional information: An entity object cannot be referenced by multiple instances of IEntityChangeTracker.
            databaseContainer.Transactions.AddObject(transaction);
            databaseContainer.Accounts.AddObject(account);
            databaseContainer.SaveChanges();
        }
    }

class AccountStateTransactionValidator : AbstractTransactionValidator
{
    override
    public bool HandleTransaction(Transaction transaction, Account account)
    {
        if (account.AccountState == null || (account.Amount < account.AccountState.LeftBound || account.Amount >= account.AccountState.RightBound))
        {
            Model1Container container = new Model1Container();
            AccountState properState = (from st in container.AccountStates
                              where st.LeftBound <= account.Amount &&
                              st.RightBound >= account.Amount
                              select st).FirstOrDefault();
            if (properState != null)
            {
               account.AccountState = properState;
            }
            else
            {
                return false;
            }
        }

        return base.nextTransaction(transaction, account);

    }
}

And I got this exception:

 at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
   at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()</ExceptionString></Exception></TraceRecord>
An unhandled exception of type 'System.InvalidOperationException' occurred in System.Data.Entity.dll`

I don't want to modify my class structure, can I use Entity Framework properly in this case? How?

Thanks for the answers.

解决方案

You're mixing multiple data contexts: account is attached to databaseContainer (databaseContainer.Transactions.AddObject(transaction); with account as a nested property from transaction) but comes from Model1Container container = new Model1Container();.

You can't use an instance of an entity in multiple contexts at the same time.

---

Also I see some kind of singleton pattern for a data container, which is generally a bad, bad, bad idea...

这篇关于实体框架System.InvalidOperationException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！