NHiernate中自定义Generator

我的这个自定义的Generator设置如下：

<generator class="HYLQ.Core.Domain.StreamGenerator, HYLQ.Core">
        <param name="ObjectName">Child</param>
      </generator>

这样我会为每个ObjectName都会产生一个顺序的流水号。
StreamGenerator的代码：

using System;
using System.Data;
using System.Data.SqlClient;
using System.Runtime.CompilerServices;
using System.Collections.Generic;
using System.Collections;
using System.Text;
using NHibernate.Id;
using NHibernate.Engine;
using NHibernate.SqlCommand;
using NHibernate.SqlTypes;
using NHibernate.Type;
using NHibernate.Util;
using NHibernate.Dialect;
using NHibernate.Mapping;

namespace HYLQ.Core.Domain
{
    class StreamGenerator : IPersistentIdentifierGenerator, IConfigurable
    {


        /**//// <summary></summary>
        public const string ObjectNameTarget = "ObjectName";

        public const string procNameTarget = "ProcedureName";

        private string objectName;
        private string procName = "usp_GetID";
        private long next;

        private System.Type returnClass;

        /**//// <summary>
        ///
        /// </summary>
        /// <param name="type"></param>
        /// <param name="parms"></param>
        /// <param name="d"></param>

        public void Configure(IType type, IDictionary parms, Dialect d)
        {
            objectName = parms[ObjectNameTarget] as string;

            if (parms[procNameTarget] != null)
            {
                procName = parms[procNameTarget] as string;
            }

            returnClass = type.ReturnedClass;
        }

        /**//// <summary>
        ///
        /// </summary>
        /// <param name="session"></param>
        /// <param name="obj"></param>
        /// <returns></returns>
        [MethodImpl(MethodImplOptions.Synchronized )]
        public object Generate(ISessionImplementor session, object obj)
        {
            if (objectName != null)
            {
                getNext(session);
            }
            return IdentifierGeneratorFactory.CreateNumber(next, returnClass);
        }

        private void getNext(ISessionImplementor session)
        {

            SqlConnection conn = (SqlConnection)session.Factory.OpenConnection();
            SqlCommand qps = conn.CreateCommand();
            qps.CommandText = procName;
            qps.CommandType = CommandType.StoredProcedure;
            qps.Parameters.Add(new SqlParameter("@ObjectName", SqlDbType.VarChar,10));
            qps.Parameters["@ObjectName"].Value = objectName;

            try
            {
                next = int.Parse(qps.ExecuteScalar().ToString());
                
            }
            catch 
            {
                throw;
            }
            finally
            {
                session.Factory.CloseConnection( conn );
            }
        }

        /**//// <summary>
        ///
        /// </summary>
        /// <param name="dialect"></param>
        /// <returns></returns>
        public string[] SqlCreateStrings(Dialect dialect)
        {
            return new string[0];
        }

        /**//// <summary>
        ///
        /// </summary>
        /// <param name="dialect"></param>
        /// <returns></returns>
        public string SqlDropString(Dialect dialect)
        {
            return null;
        }

        /**//// <summary></summary>
        public object GeneratorKey()
        {
            return objectName;
        }
    }
}

这里是调用一个存储过程来生成流水号的。
存储过程和表的定义如下：

--流水号
create table Stream
(
    ObjectName        varchar(10)        not null,        --对象名
    MaxID            int                not null,        --流水号
    primary key(ObjectName)
)
go

--流水号发生器
if exists(select * from sysobjects where type='p' and name='usp_GetID')
    drop proc usp_GetID
go
create proc usp_GetID
(
    @ObjectName        varchar(10)            --对象名
)
as
begin
    declare @MaxID int
    SET NOCOUNT ON

    if exists(select * from Stream where ObjectName=@ObjectName)
    begin
        select @MaxID=MaxID from Stream where ObjectName=@ObjectName
        update Stream set MaxID=MaxID+1 where ObjectName=@ObjectName
    end
    else
    begin
        set @MaxID=1
        insert into Stream values(@ObjectName,2)
    end
    
    select @MaxID as MaxID
end
go

希望对大家能有所帮助！