I am attempting to add a child record to an Oracle database using NHibernate in C#. I added a function to my Parent class called "AddChild" that looks like this:

public void AddChild(Child c)
{
c.Child = this;
this.Children.Add(c);
}

On the line that says "this.Children.Add(c)", I get the following exception:
NotSupportedException was unhandled: Collection was of a fixed size.

How can I set the collection to not have a fixed size?

Thanks.

Can you post the declaration of Children ? What kind of collection do you use ?

private IList mChildren = new ArrayList();

public virtual System.Collections.IList Children
{
get
{
return mChildren;
}
set
{
mChildren = value;
}
}

ArrayList should't be fixed size per default. When you get the exception, are you working on a persisted object (loaded with hibernate) and is Children or mChidlren part of the mapping ?

Yes, I am working on a persisted object loaded with nhibernate. I first retrieve the parent object, then I am calling the AddChildren function from that object.

Children is indeed part of the mapping, here is what the mapping looks like:

<bag name="Children" inverse="true" lazy="false">
<key column="Parent_Id" />
<one-to-many class="Template.Domain.Child, Template.Domain" />
</bag>

I appreciate you working through this with me. Let me know if you need any additional information.

Currently I have no real idea. Can you post the mappings of parent and child and the code you use for loading the object ?

Okay from now on I will use the actual class names for parent and child. Parent is "ApplicationCntl" and Child is "ApplicationCntlDtl". I kept those generic in my last few posts to make it easier to read.

Here is the mapping for the parent:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="false" default-cascade="save-update">
<class name="Template.Domain.ApplicationCntl, Template.Domain" table="Application_Cntl">
<id name="Id" type="Int32" column="Application_Cntl_Id">
<generator class="identity" />
</id>
<property name="ApplicationCntlCd" column="Application_Cntl_Cd" type="String" />
<property name="ApplicationCntlDesc" column="Application_Cntl_Desc" type="String" />
<bag name="ApplicationCntlDtls" inverse="true" lazy="false">
<key column="Application_Cntl_Id" />
<one-to-many class="Template.Domain.ApplicationCntlDtl, Template.Domain" />
</bag>
<bag name="ApplicationCntlDtlsIListLazyFalse" inverse="true" lazy="false">
<key column="Application_Cntl_Id" />
<one-to-many class="Template.Domain.ApplicationCntlDtl, Template.Domain" />
</bag>
<bag name="ApplicationCntlDtlsIListLazyTrue" inverse="true" lazy="true">
<key column="Application_Cntl_Id" />
<one-to-many class="Template.Domain.ApplicationCntlDtl, Template.Domain" />
</bag>
<property name="CreateDate" column="Create_Date" type="DateTime" />
<property name="UpdateDate" column="Update_Date" type="DateTime" />
<property name="UpdateSource" column="Update_Source" type="String" />
</class>
</hibernate-mapping>

Here is the mapping for the child:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-lazy="false" default-cascade="save-update">
<class name="Template.Domain.ApplicationCntlDtl, Template.Domain" table="Application_Cntl_Dtl">
<id name="Id" type="Int32" column="Application_Cntl_Dtl_Id">
<generator class="identity" />
</id>
<many-to-one name="ApplicationCntl" column="Application_Cntl_Id" class="Template.Domain.ApplicationCntl, Template.Domain" />
<property name="ApplicationCntlDtlValueDesc" column="Application_Cntl_Dtl_Desc" type="String" />
<property name="CreateDate" column="Create_Date" type="DateTime" />
<property name="UpdateDate" column="Update_Date" type="DateTime" />
<property name="UpdateSource" column="Update_Source" type="String" />
</class>
</hibernate-mapping>

And here is the code I use for loading the object (note that mISession is an Nhibernate ISession object that is open, and that the bolded line is the one that errors):

ITransaction transaction = mISession.BeginTransaction();

Template.Domain.ApplicationCntl applCntl = mISession.Load("ApplicationCntl".GetType(), 2);

IQuery customQuery = mISession.CreateQuery("From ApplicationCntl");
IList<Template.Domain.ApplicationCntl> applCntlList = customQuery.List();

Template.Domain.ApplicationCntlDtl applCntlDtl = new Template.Domain.ApplicationCntlDtl();

applCntl.AddApplicationCntlDtl(applCntlDtl);
applCntlList.Add(applCntl);

Why are you mapping the same children to three different collections in the parent object ?



Can you reduce the mapping to one collection and try again.

Is there some special code in your properties for accessing the lists (e.g. converting them to a read only collection or sth like that) ?

I had a few extra mapping of the same children for some testing I was doing. I removed those mappings and tried again, but no luck. As far as I am aware, there is no special code in my properties for accessing the lists.

Strange ! Can you check the actual type of applCntl.ApplicationCntlDtls after you've loaded the object and if that list is of fixed size ?

What are you doing in applCntl.AddApplicationCntlDtl(applCntlDtl) ?

The type of applCntl.ApplicationCntlDtls after being loaded is Systems.Collections.IList {object[]} and the IsFixedSize property is true.

Here is what I am doing in applCntl.AddApplicationCntlDtl(applCntlDtl):

public virtual void AddApplicationDtl(ApplicationCntlDtl applCntlDtl)
{
applCntlDtl.ApplicationCntl = this;
ApplicationCntlDtls.Add(applCntlDtl);
}

The error occurs at ApplicationCntlDtls.Add(applCntlDtl);

The list shoud be something like NHibernate.Collection... can you change your mapping and class to a generic list ?

IList<Template.Domain.Child>

For me it looks like you get an plain array loaded into your class. Which hibernate version and .Net version do you use ?

I change my ApplicationCntl class declaration of mApplicationCntlDtls from

private IList mApplicationCntlDtls = new ArrayList();

to

private IList<ApplicationCntlDtl> mApplicationCntlDtls = new List<ApplicationCntlDtl>();

Now the actual type of applCntl.ApplicationCntlDtls after I've loaded the object is System.Collections.Generic.IList<Template.Domain.ApplicationCntlDtl> {Template.Domain.ApplicationCntlDtl[]}

There is no "IsFixedSize" property on this object. I still get the error.

I am using NHibernate version 1.2.0.4 and .Net version 2.0.50727

Did you also change the type of the property ?

Yes, I did.