Since when is float 0.0 not valid?

Hi -

I have a column defined as follows:

    [ValidatePresence]
    private double _min;

In the database, is is a non-nullable field.
In this case, 0.0 is a valid value, and the last time I tried it I had no problems.  Now I'm getting the following error:

There was an error processing the request
Mindscape.LightSpeed.Validation.ValidationException: The object [TestRecord [Id=-21, EntityState=New]] could not be saved because it is invalid.

The errors are:

XmlDevices item 1 is invalid
  XmlDeviceFields item 0 is invalid
    Min is required
  XmlDeviceFields item 1 is invalid
    Min is required
    XmlDevice is invalid

   at  .\a. (Entity )
   at  .\a. (Entity , ICollection`1 )
   at  .\a. (Entity , List`1 )
   at  .\a. (UnitOfWorkBase , IEnumerable`1 , IEnumerable`1 )
   at Mindscape.LightSpeed.UnitOfWork.SaveChanges(Boolean reset)
   at Mindscape.LightSpeed.UnitOfWorkBase.SaveChanges()
   at Services.TestingService.SaveTestResults(TestRecord incomingTestRecord) in E:\VisualStudio2010\Projects\ProductionMonitor\Services\TestingService.cs:line 113

This is the same code and data I have run successfully not too long ago, but probably prior to the release of Lightspeed V4.

Has something changed?  Is this expected behavior?  I may be able to work around it (haven't tried yet), but it seems this should
really be a valid value.  Other posts seem to indicate a default value will not be considered "not present", so I'm thinking this
may be an error...

Thanks,
Dave

Hello Dave,

This is expected behaviour, and I'm surprised it ever passed validation.  As you note, a default value is considered "not present," and since 0.0 is the default value for double, a value of 0.0 is considered "not present."  The reason for this is that the _min field always has a value -- this is enforced by the .NET type system -- the semantics of presence validation are therefore more 'someone has set the value (away from the default).'

If you are willing to accept 0.0 for _min, then you should remove the ValidatePresence attribute, because there is effectively no requirement to set a value for _min -- the default will do.

Alternatively, you could do something like setting _min = Double.NaN in the constructor, and using a custom validation to check that the value is no longer NaN.

Thanks, Ivan.  I don't know why it was working, but I can see where .NET has to have something there.  The database is happy setting it to DBNull, but that's a concept not natively supported by .NET...