int and short inheritance discriminators

Hi,

LightSpeed throws an exception whenever I try to insert a new object through Dynamic Data when the Entity is a child of another Entity and discriminated by a byte or short property. It works fine with int discriminators but I would prefer to define smaller data storage requirements when I know that there will be less than 256 child classes (pretty much all cases really!)

The exception message seems to boil down to this inner exception:

Object of type 'System.Int32' cannot be converted to type 'System.Nullable`1[System.Int16]'.

    at Mindscape.LightSpeed.Model.FieldModel.SetValueSlow(Object , Object )
   at Mindscape.LightSpeed.Model.TypeModel.[square symbol that crashes your forum software](Entity )
   at Mindscape.LightSpeed.Entity.Initialize()
   at Mindscape.LightSpeed.Entity..ctor(Boolean autoInitialize)
   at Mindscape.LightSpeed.Entity..ctor()
   at Mindscape.LightSpeed.Entity`1..ctor()
   at WebApplication1.Entity2..ctor()
   at WebApplication1.Entity1..ctor()

I can just use the int32 workaround for now but I'll need to get the database schema signed off by my manager fairly soon so the fewer temporary workarounds I have to highlight the better :-) Do you have any better suggestions or a permanent fix?

Thanks,

Chris

This sounds like it's a problem with the discriminator declaration rather than something specific to Dynamic Data.  Could you provide us with:

1. The DiscriminatorAttribute declaration on the derived type (e.g. [Discriminator(Attribute="Kind", Value=123)]).

2. The field declaration for the discriminator field in the base type (e.g. private short _kind;).

3. If you are using the designer, the <baseToDerivedAssociation> element from the .lsmodel XML file (e.g. <baseToDerivedAssociation discriminatorName="Kind" ... >...</baseToDerivedAssociation>.

Thanks!

 Hi Ivan,

Here is one example:

1) [Discriminator(Attribute="EventType", Value=1)]

2) private byte _eventType;

3) I am using the designer... 

<baseToDerivedAssociation discriminatorName="EventType" discriminatorType="Byte" discriminatorValue="1">
          <entityMoniker name="/Warehouse/ExternalDataEvent" />
        </baseToDerivedAssociation>

Trying to add an ExternalDataEvent through DD throws the previously mentioned exception.

Thanks,

Chris

Thanks.  This appears to be a general LightSpeed issue rather than specific to Dynamic Data.  I've committed a fix and it will be included in nightlies dated 14 Aug 2009 and above.

 Thanks Ivan, this is indeed fixed in 20090919 :-)

Chris