Question

What is the best way to map UInt32 type to sql-server int type with NHibernate.

The value is a picture width/height so negative value are not make sense here.

But maybe I should use int because NHibenate doesn’t support unassigned ints.

Answer 1

You can map the column with an IUserType.

<class name="UnsignedCounter">
    <property name="Count" type="mynamespace.UInt32Type, mydll"  />
</class>

And the IUserType which maps UInt32? and UInt32.

class UInt32Type : IUserType
{
    public object NullSafeGet( System.Data.IDataReader rs, string[] names, object owner )
    {
        int? i = (int?) NHibernateUtil.Int32.NullSafeGet( rs, names[0] );
        return (UInt32?) i;
    }

    public void NullSafeSet( System.Data.IDbCommand cmd, object value, int index )
    {
        UInt32? u = (UInt32?) value;
        int? i = (Int32?) u;
        NHibernateUtil.Int32.NullSafeSet( cmd, i, index );
    }

    public Type ReturnedType
    {
        get { return typeof(Nullable<UInt32>); }
    }

    public SqlType[] SqlTypes
    {
        get { return new SqlType[] { SqlTypeFactory.Int32 }; }
    }

    public object Assemble( object cached, object owner )
    {
        return cached;
    }

    public object DeepCopy( object value )
    {
        return value;
    }

    public object Disassemble( object value )
    {
        return value;
    }

    public int GetHashCode( object x )
    {
        return x.GetHashCode();
    }

    public bool IsMutable
    {
        get { return false; }
    }

    public object Replace( object original, object target, object owner )
    {
        return original;
    }

    public new bool Equals( object x, object y )
    {
        return x != null && x.Equals( y );
    }
}