Generic custom collections, iBATIS.NET and Unity.

Hi,

I'm trying to use a generic custom collection interface (to support injection with Microsoft Patterns and Practices Unity) in a class O/R mapped with iBATIS.NET.  Does anyone know if this is possible and if so how to do it?

I have an IDataItemCollection<T> interface that I map to SqlDataItemCollection<T> which extends CollectionBase.  I want to use the IDataItemCollection<T> in my classes so I can swap SqlDataItemCollection<T> with other classes that extend the interface through Unity.  The iBATIS.NET mapping file can reference the concrete class directly as there won't be one without the other.

Below I have included a very simplified example of the code, database and mappings.  I'm completely new to iBATIS.NET and really just want to prove its use at the moment, so please re-jig the mapping XML as necessary.

Many thanks,

Paul

public interface IDataItem
{
	object Id { get; set; }
}
 
public class DataItem : IDataItem
{
	public object Id { get; set; }
}
 
public interface IDataItemCollection<T> : ICollection where T : IDataItem
{
	// Various Getters and Setters
...
}
 
public class SqlDataItemCollection<T> : CollectionBase, IDataItemCollection<T> where T : DataItem
{
	public SqlDataItemCollection() { }
	public SqlDataItemCollection(T injType) { }
 
	// Getters and Setters to implement interfaces
...
}
 
public class Foo : DataItem
{
	public Foo(IDataItemCollection<Bar> bars)
	{
		Bars = bars;
	}
 
	public IDataItemCollection<Bar> Bars { get; set; }
}
 
public class Bar : DataItem { }
 
 
 
-- SQL Server 2005 Database
 
CREATE TABLE Foo
(
	Id bigint IDENTITY(1,1)
)
 
CREATE TABLE Bar
(
	Id bigint IDENTITY(1,1)
)
 
CREATE TABLE FooBar
(
	FooId bigint,
	BarId bigint
)
 
 
 
<!-- iBATIS.NET mapping.xml -->
 
<resultMaps>
	<resultMap id="FooResult" class="Foo">
		<result property="Id" column="Id"/>
		<result property="Bars" column="Id" select="SelectBarsInFoo" lazyLoad="false"/>
	</resultMap>
 
	<resultMap id="BarResult" class="Bar">
		<result property="Id" column="Id"/>
	</resultMap>
</resultMaps>
 
<statements>
	<select id="SelectFoo" resultMap="FooResult">
		SELECT Id
      		FROM Foo
	</select>
 
	<select id="SelectBarsInFoo" parameterClass="long" resultMap="BarResult" listClass="SqlDataItemCollection`1[Bar]" >
		SELECT Bar.Id
		FROM Bar
		JOIN FooBar ON Bar.Id = FooBar.BarId
		WHERE FooBar.FooId = #value#
	</select>
</statements>

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