That might work for instances of direct comparison, but what of an extension
method where the arguments are different... for example this theoretical
method:
public static bool ExampleMethod(this int x, ExampleType y) { ... }
In this example you have a usage but the usage isn't going to help you guess
the mapping type for ExampleType. The only way I can think of doing that is
with the extension method patch. If you have another idea I'd be excited to
hear it though. Otherwise would that be an acceptable solution and should I
go ahead with it?
On Thu, Aug 19, 2010 at 9:58 PM, Fabio Maulo <[email protected]> wrote:
> ExpressionParameterVisitor
> NHibernateUtil.GuessType(expression.Type)
>
> We can't guess the type without the "usage context".
> myClass.MyProperty == something
>
> to really guess/know the type of "something" we have to know the mapping
> of "MyProperty".
>
> We may have an ugly patch-extension method where the user can specify the
> NH's IType but... well... that will be a patch not a solution.
>
> On Thu, Aug 19, 2010 at 3:46 PM, David Pfeffer <[email protected]> wrote:
>
>> Right, which is exactly what I'm working on right now...
>>
>> What I'm proposed is a fix for the issues relating to the LINQ provider
>> custom types. What do you all think of the solution?
>>
>>
>> On Thu, Aug 19, 2010 at 11:41 AM, Fabio Maulo <[email protected]>wrote:
>>
>>> I think that first we have to fix issues related to Linq-Provider and
>>> custom-types then we have to add some linq-extensions inside
>>> NHibernate-Spatial (as it has HQL extensions).
>>>
>>>
>>> On Thu, Aug 19, 2010 at 11:02 AM, David Pfeffer <[email protected]>wrote:
>>>
>>>> An example from NH Spatial --
>>>>
>>>> I have a type...
>>>>
>>>> public class Breadcrumb
>>>> {
>>>> public virtual int Id { get; set; }
>>>> public virtual IGeometry Position { get; set; }
>>>> public virtual string Description { get; set; }
>>>> }
>>>>
>>>> ...and in my code I do the following...
>>>>
>>>> IGeometry center;
>>>> // code here to set the center to a useful point
>>>> var breadcrumbsWithinDistance = session.Query<Breadcrumb>().Where(x =>
>>>> x.Position.Distance(center) < 500);
>>>>
>>>> Now, how would the LINQ engine know the mapping of *center*? Since it
>>>> isn't a property of a mapped class there's nothing already specified here
>>>> for what user type to use.
>>>>
>>>> I propose that line could be replaced as...
>>>>
>>>> var breadcrumbsWithinDistance = session.Query<Breadcrumb>().Where(x =>
>>>> x.Position.Distance(center.AsUserType(new
>>>> NHibernate.Type.CustomType(typeof(NHibernate.Spatial.Type.MsSql2008GeographyType),
>>>> null)
>>>> )) < 500);
>>>>
>>>> (or whatever other user type is appropriate for that database engine)
>>>>
>>>> What do you think?
>>>>
>>>>
>>>> On Mon, Aug 16, 2010 at 5:16 PM, Fabio Maulo <[email protected]>wrote:
>>>>
>>>>>
>>>>> El 16/08/2010, a las 12:14, David Pfeffer <[email protected]>
>>>>> escribió:
>>>>>
>>>>> I would attempt to write a fix, but this isn't just a bug. There's a
>>>>> design issue to be resolved here as to how to go about implementing this.
>>>>>
>>>>>
>>>>> I'm not so sure about " a design issue"...
>>>>>
>>>>>
>>>>> One idea I have is to create an extension method, WithUserType(this
>>>>> object obj, IType type) that will be used to inform the LINQ provider as
>>>>> to
>>>>> the type (UserType, etc.).
>>>>>
>>>>>
>>>>> Try to write an example where the Type can't be inferred.
>>>>> Thanks.
>>>>>
>>>>>
>>>>> If this sounds like a good idea, would anyone be able to provide a few
>>>>> pointers as to where to look to hook this in? I will take a look and see
>>>>> if
>>>>> I can patch.
>>>>>
>>>>> Thanks.
>>>>>
>>>>> On Mon, Aug 16, 2010 at 10:53 AM, Fabio Maulo < <[email protected]>
>>>>> [email protected]> wrote:
>>>>>
>>>>>> Known issue
>>>>>> <http://216.121.112.228/browse/NH/component/10120>
>>>>>> http://216.121.112.228/browse/NH/component/10120
>>>>>>
>>>>>>
>>>>>> On Fri, Aug 13, 2010 at 2:54 PM, David Pfeffer <<[email protected]>
>>>>>> [email protected]> wrote:
>>>>>>
>>>>>>> Hello all,
>>>>>>>
>>>>>>> So I'm having a bit of difficulty trying to build a LINQ to NH
>>>>>>> Spatial provider. Specifically, I have not found a way to specify the
>>>>>>> user
>>>>>>> type for IGeometry types. So, even though I have the backend LINQ parser
>>>>>>> code plugged in, queries fail due to "No persister for:
>>>>>>> GeoAPI.Geometries.IGeometry."
>>>>>>>
>>>>>>> In Criteria and HQL specifying the user type is easy. How do I
>>>>>>> specify the user type for a LINQ query so that my backend code is
>>>>>>> invoked?
>>>>>>>
>>>>>>> Thanks!
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Fabio Maulo
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>>
>>> --
>>> Fabio Maulo
>>>
>>>
>>
>
>
> --
> Fabio Maulo
>
>
