NHibernate代理引起数据绑定问题 [英] NHibernate proxy causing problems with databinding

问题描述

我有一个gridview绑定到nhibernate查询的结果。如果列表中的第一个项目被编辑，将抛出以下异常：

System.Reflection.TargetException：对象不匹配目标类型

似乎问题是由于数据绑定无法处理列表中的第一个项目，而是其他项目的子类型在列表中。

什么是一个很好/正确的方法来解决这个问题？目前我不得不关闭nhibernate代理。

编辑：我有另外两个解决方案：

• 克隆列表中的所有内容（ http://steve-fair-dev.blogspot.com/2007/08/databind-object-does-not-match-target.html ） - 这对我来说不起作用，因为对象不实现ICloneable


• 更改列表中的项目顺序，以便代理不是第一个（ http://community.devexpress.com/forums/t/30797.aspx ） - 这是如此的黑客我不认为我可以低于这个低点！

b $ b

解决方案

由于列表中的代理对象（从延迟加载）导致根本原因，或因为列表不是同构的包含多个类型，即使它们属于同一个类层次结构）？非均匀数据集的问题是已知的限制。请参阅此和这个。

我不认为除了不使用数据绑定来填充网格之外，还有一个解决方案。这很容易，只要它是只读的。

I have a gridview that is bound to the result from an nhibernate query. If the first item in the list is edited the following exception is thrown:

System.Reflection.TargetException: Object does not match target type

It appears that the problem is caused by the fact that databinding can't deal with the first item in the list being a subtype of the other items in the list.

What is a nice / correct way to solve this problem? Currently I have had to turn off nhibernates proxying.

Edit: I have another couple of solutions:

• Clone everything in the list (http://steve-fair-dev.blogspot.com/2007/08/databind-object-does-not-match-target.html) - this doesn't work for me as the object doesn't implement ICloneable
• change the order of items in the list so that the proxy isn't first (http://community.devexpress.com/forums/t/30797.aspx) - this is so hacky, I don't think I can stoop this low!

But none of these feel right though...

解决方案

Is the root cause due to a proxy object in the list (from lazy loading) or because the list isn't homogeneous (contains multiple types even if they belong to the same class hierarchy)? The problem with non-homogeneous data sets is a known limitation. See this and this.

I don't think there's a solution other than to not use databinding to populate the grid. That's easy enough if it's read-only.

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