.net 如何检查对象是否附加到ObjectContext？

我需要将EF对象（以前分离）附加到新的ObjectContext。问题是，我不知道它之前是否已连接或加载。如果有一个对象具有加载到ObjectContext的相同键，则在尝试附加时会出现异常。有没有办法检查是否存在已附加特定密钥的对象

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谢谢

对象上下文中对象的状态由管理

来自MSDN:

int orderId = 43680;

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    ObjectStateManager objectStateManager = context.ObjectStateManager;
    ObjectStateEntry stateEntry = null;

    var order = (from o in context.SalesOrderHeaders
                 where o.SalesOrderID == orderId
                 select o).First();

    // Attempts to retrieve ObjectStateEntry for the given EntityKey.
    bool isPresent = objectStateManager.TryGetObjectStateEntry(((IEntityWithKey)order).EntityKey, out stateEntry);
    if (isPresent)
    {
        Console.WriteLine("The entity was found");
    }
}

// The changes are tracked as they occur and the state of the object is Modified.
Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(newItem).State);

另见：

来自上一个MSDN链接：

int orderId = 43680;

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    ObjectStateManager objectStateManager = context.ObjectStateManager;
    ObjectStateEntry stateEntry = null;

    var order = (from o in context.SalesOrderHeaders
                 where o.SalesOrderID == orderId
                 select o).First();

    // Attempts to retrieve ObjectStateEntry for the given EntityKey.
    bool isPresent = objectStateManager.TryGetObjectStateEntry(((IEntityWithKey)order).EntityKey, out stateEntry);
    if (isPresent)
    {
        Console.WriteLine("The entity was found");
    }
}

// The changes are tracked as they occur and the state of the object is Modified.
Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(newItem).State);

。。我想在您的情况下，这可能是一个缓存项

---

希望有帮助

对象上下文中对象的状态由管理

来自MSDN:

int orderId = 43680;

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    ObjectStateManager objectStateManager = context.ObjectStateManager;
    ObjectStateEntry stateEntry = null;

    var order = (from o in context.SalesOrderHeaders
                 where o.SalesOrderID == orderId
                 select o).First();

    // Attempts to retrieve ObjectStateEntry for the given EntityKey.
    bool isPresent = objectStateManager.TryGetObjectStateEntry(((IEntityWithKey)order).EntityKey, out stateEntry);
    if (isPresent)
    {
        Console.WriteLine("The entity was found");
    }
}

// The changes are tracked as they occur and the state of the object is Modified.
Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(newItem).State);

另见：

来自上一个MSDN链接：

int orderId = 43680;

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    ObjectStateManager objectStateManager = context.ObjectStateManager;
    ObjectStateEntry stateEntry = null;

    var order = (from o in context.SalesOrderHeaders
                 where o.SalesOrderID == orderId
                 select o).First();

    // Attempts to retrieve ObjectStateEntry for the given EntityKey.
    bool isPresent = objectStateManager.TryGetObjectStateEntry(((IEntityWithKey)order).EntityKey, out stateEntry);
    if (isPresent)
    {
        Console.WriteLine("The entity was found");
    }
}

// The changes are tracked as they occur and the state of the object is Modified.
Console.WriteLine(context.ObjectStateManager.GetObjectStateEntry(newItem).State);

。。我想在您的情况下，这可能是一个缓存项

---

希望有帮助

是的，我有同样的想法，现在检查它是否能与POCO对象一起工作。是的，我有同样的想法，现在检查它是否能与POCO对象一起工作。