ConstraintException thrown when posting empty data for non-nullable properties
05 Jul 2010
I am currently working with model validation in ASP.NET, using an Entity Framework 4
DataAnnotations and partial classes with
In my model, I have an
Employee entity for which some properties are non-nullable.
I have also created a partial class and a meta data class for this class, to be used
with model validation, as described in this blog post.
This approach works great. The Employee class is validated properly, with a minimum effort. My entities are validated with standard validation attributes, as well as a set of custom ones. Lovely.
However, the application crashes when I post empty text input elements in the Create
and Edit views. A
ConstraintException is thrown before any view controller actions
are executed, which means that I cannot act on the constraint exception in my action.
The exception occurs since the empty posted data causes the corresponding properties
Employee class to be set to
null, which conflicts with the non-null setup
in the entity model.
However, since I have custom validation classes where I use
Required attributes to
make properties mandatory, I do not need the non-nullable attributes in my model. As
such, I set the nullable property to (None)…and the ConstraintException is history!