NHibernate自定义数据类型-技术开发专区

NHibernate自定义数据类型

作者：ITPUB论坛编辑： nancy 2008-07-01 00:00

【IT168技术文档】

可以通过实现IUserType或者ICompositeUserType接口来实现这一功能。 ICompositeUserType较IUserType而言可以提供更多的控制。一般情况我们实现IUserType即可。

比如：我想实现在数据库里存储格式为“数据；数据；数据”，而在类中体现为IList。这样我们可以减少一些一对多的映射。我们可以用它来存放EMail等数据。

自定义数据类：

using System;
using System.Collections;
using System.Data;
using System.Text;
using NHibernate;
using NHibernate.SqlTypes;
namespace Index.Data.NHibernateHelper
{
/**//// <summary>
/// 自定义的NH数据类型，使用；分隔存储多个数据
/// </summary>
    public class DDLList : IUserType
{
private static readonly char SPLITTER = ';';
private static readonly SqlType[] TYPES = new SqlType[] {NHibernateUtil.String.SqlType};
IUserType 成员#region IUserType 成员
/**//// <summary>
/// 提供自定义的完全复制方法
/// </summary>
/// <param name="value"></param>
/// <returns></returns>
        public object DeepCopy(object value)
{
if (value == null)
{
return null;
}
IList sourceList = (IList) value;
IList targetList = new ArrayList();
for (int i = 0; i < sourceList.Count; i++)
{
targetList.Add(sourceList[i]);
}
return targetList;
}
/**//// <summary>
/// 本类型实例是否可变
/// </summary>
        public bool IsMutable
{
get { return false; }
}
/**//// <summary>
/// 返回数据
/// </summary>
/// <param name="rs"></param>
/// <param name="names"></param>
/// <param name="owner"></param>
/// <returns></returns>
        public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
string value = (string) NHibernateUtil.String.NullSafeGet(rs, names[0]);
if (value != null)
{
return StringToList(value);
}
else
{
return null;
}
}
/**//// <summary>
/// 设置数据
/// </summary>
/// <param name="cmd"></param>
/// <param name="value"></param>
/// <param name="index"></param>
        public void NullSafeSet(IDbCommand cmd, object value, int index)
{
if (value != null)
{
string str = ListToString((IList) value);
NHibernateUtil.String.NullSafeSet(cmd, str, index);
}
else
{
NHibernateUtil.String.NullSafeSet(cmd, value, index);
}
}
/**//// <summary>
/// 返回的Sql
/// </summary>
        public Type ReturnedType
{
get { return typeof (IList); }
}
/**//// <summary>
/// 返回的Sql类型
/// </summary>
        public SqlType[] SqlTypes
{
get { return TYPES; }
}
public new bool Equals(object x, object y)
{
if (x == y)
{
return true;
}
if (x != null && y != null)
{
IList xList = (IList)x;
IList yList = (IList)y;
if (xList.Count != yList.Count)
{
return false;
}
for (int i = 0; i < xList.Count; i++)
{
string str1 = (string)xList[i];
string str2 = (string)yList[i];
if (str1 != str2)
{
return false;
}
}
return true;
}
return false;
}
#endregion
/**//// <summary>
/// 将string拼装成一个字符串，以“；”分隔
/// </summary>
/// <param name="list"></param>
/// <returns></returns>
        private string ListToString(IList list)
{
if (list.Count == 0)
{
return null;
}
StringBuilder sb = new StringBuilder();
for (int i = 0; i < list.Count - 1; i++)
{
sb.Append(list[i]).Append(SPLITTER);
}
sb.Append(list[list.Count - 1]);
return sb.ToString();
}
/**//// <summary>
/// 将“；”分隔的字符串解析为数组
/// </summary>
/// <param name="value"></param>
/// <returns></returns>
        private IList StringToList(string value)
{
string[] strs = value.Split(SPLITTER);
IList emailList = new ArrayList();
for (int i = 0; i < strs.Length; i++)
{
emailList.Add(strs[i]);
}
return emailList;
}
}
}

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