NHibernate返回字典<int, string>

Question

Is it possible to return Dictionary <int, string> from an nhibernate query such as this:

CreateQuery("select CustomerId, FullName from Customer")  

I've tried a few examples from this forum using the .net ToDictionary method, but am unable to get them to work.

Answer 1

您需要在列表中进行以下操作或枚举，并且应该得到字典

.ToDictionary(x => x.CustomerId, x => x.FullName);

Answer 2

I am not aware of any way how to do this directly in NH. ISession does not provide it, ICriteria neither. IResultTransformer just converts simple entities and lists of entities to lists.

Of course there is workaround:

CreateQuery<Customer>("select CustomerId, FullName from Customer")
.ToList<Customer>() // since now working on real objects
.ToDictionary(x => x.CustomerId, x => x.FullName)

However, this is not ideal since you convert results to list just to be able to convert it to dictionary. So there is one additional transformation degrading performance.