Not directly. But the following description, which was posted on the mailing list, explains how:
On 8 Jul 2005, at 14:37, Romano Zabini wrote:
I'm part of a team developing an Asp.NET system using NEO as OR framework.
As we didn't like handling null values by means of the "HandleNullValueForProperty" method, we are now trying to use the NullableTypes library.
NullableTypes (nullabletypes.sourceforge.net) is a library which defines a sort of extended base types which "wrap" base types, allowing null values. For instance the classes NullableInt32, NullableDateTime, etc.
In order to work with these types, we had to make some modifications to NEO source code. Here is a description of the changes we made, should someone be interested.
1) We changed the NeoSupport.vtl template as follows:
and so on for the other base types.
So if the attribute is not required, we have in the base class a property like:
And no need to define HandleNullValueForProperty.
2) A couple of modifications have to be done in NEO source code, in order to have all the tests pass. Basically we have to convert a non-null NullableType into its corresponding .Net base type, before we can compare it to a base type value. NullableTypes have a property Value which returns its "wrapped" base type - when the object IsNull property is false.
We had to insert the following fragment:
as first lines in the "public bool IsTrueForValue(object aValue, object nullVal)" method, both in the class EqualsPredicate and in the class RelationalPredicateBase.
Then we had to modify the "public ColumnQualifier ConvertToColumnQualifier(PropertyQualifier propQualifier)" in the class QualifierConverter as follows:
Up to now these are the only changes we had to implement to have out NullableTypes-version of NEO working. As we are currently coding our application, there may be some other changes to make in NEO source.