c# 类型拷贝

/// <summary>
/// 类 名：EntityHelper
/// 类 说 明：实体操作方法类
/// ：
/// 创建时间：2013/8/12
/// </summary>
public static class EntityHelper
{
/// <summary>
/// 方 法 名：DataRowToEntity
/// 方法说明：转化数据行到实体对象
/// ：
/// 创建时间：2013/8/12
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="dr">数据行</param>
/// <param name="excludefields">不进行赋值的字段</param>
/// <returns>实体对象</returns>
public static T DataRowToEntity<T>(DataRow dr, string excludefields) where T : new()
{
Type t = typeof(T);
PropertyInfo[] pinfos = t.GetProperties();
T obj = new T();
foreach (PropertyInfo pi in pinfos)
{
if (!dr.Table.Columns.Contains(pi.Name))
continue;
if (!string.IsNullOrWhiteSpace(excludefields) && excludefields.Contains(pi.Name))
continue;
if (dr[pi.Name] != DBNull.Value)
pi.SetValue(obj, dr[pi.Name], null);
else
pi.SetValue(obj, null, null);
}
return obj;
}
/// <summary>
/// 方 法 名：DataRowToEntity
/// 方法说明：转化数据行到实体对象
/// ：
/// 创建时间：2013/8/12
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="dr">The dr.</param>
/// <returns></returns>
public static T DataRowToEntity<T>(DataRow dr) where T : new()
{
return DataRowToEntity<T>(dr, string.Empty);
}
/// <summary>
/// 方 法 名：DataTableToEntityList
/// 方法说明：转化数据行到实体对象
/// ：
/// 创建时间：2013/8/12
/// </summary>
/// <typeparam name="T">实体类</typeparam>
/// <param name="dt">数据表</param>
/// <returns></returns>
public static List<T> DataTableToEntityList<T>(DataTable dt) where T : new()
{
return DataTableToEntityList<T>(dt,null);
}

/// <summary>
/// 方 法 名：DataTableToEntityList
/// 方法说明：转化数据行到实体对象
/// ：
/// 创建时间：2013/8/12
/// </summary>
/// <typeparam name="T">实体类</typeparam>
/// <param name="dt">数据表</param>
/// <param name="excludefields">不进行赋值的字段</param>
/// <returns></returns>
public static List<T> DataTableToEntityList<T>(DataTable dt,string excludefields) where T : new()
{
List<T> list = new List<T>();
if (dt != null)
{
foreach (DataRow dr in dt.Rows)
{
T t = DataRowToEntity<T>(dr,excludefields);
if (t != null)
list.Add(t);
}
}
return list;
}
/// <summary>
/// 复制实体
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="source"></param>
/// <returns></returns>
public static T CopyEntity<T>(T source) where T : new()
{
Type t = typeof(T);
PropertyInfo[] pinfos = t.GetProperties();
T obj = new T();
foreach (PropertyInfo pi in pinfos)
{
object v = GetMemberValue(source,pi);
pi.SetValue(obj, v, null);
}
return obj;
}
/// <summary>
/// 判断两个实体是否一样
/// </summary>
/// <param name="source"></param>
/// <param name="dest"></param>
/// <returns></returns>
public static bool CheckEntityEquals(object source, object dest)
{
Type t = source.GetType();
PropertyInfo[] pinfos = t.GetProperties();
foreach (PropertyInfo pi in pinfos)
{
object v1 = GetMemberValue(dest, pi);
object v = GetMemberValue(source, pi);
if (!object.Equals(v1, v))
return false;
}
return true;
}

/// <summary>
/// 方法说明：获取实体成员的值
/// 作 者：
/// 创建时间：2013/9/14
/// </summary>
/// <param name="entity">实体</param>
/// <param name="member">实体成员信息</param>
/// <returns>实体成员的值</returns>
public static object GetMemberValue(object entity, MemberInfo member)
{
if ((entity == null) || (member == null))
{
return null;
}

object value = null;

switch (member.MemberType)
{
case MemberTypes.Field:
FieldInfo field = member as FieldInfo;
if (field != null)
{
value = field.GetValue(entity);
}
break;
case MemberTypes.Property:
PropertyInfo property = member as PropertyInfo;
if (property != null)
{
value = property.GetValue(entity, null);
}
break;
default:
break;
}

return value;
}
/// <summary>
/// 方法说明：获取实体成员的值
/// 作 者：
/// 创建时间：2013/9/14
/// </summary>
/// <param name="entity">实体</param>
/// <param name="memberName">实体成员名称</param>
/// <param name="ignoreCase">是否忽略大小写</param>
/// <returns>实体成员的值</returns>
public static object GetMemberValue(object entity, string memberName, bool ignoreCase)
{
if ((entity == null) || (string.IsNullOrEmpty(memberName)))
{
return null;
}

MemberInfo[] members;
if (ignoreCase)
{
members = entity.GetType().GetMember(memberName, BindingFlags.Public | BindingFlags.IgnoreCase | BindingFlags.Instance);
}
else
{
members = entity.GetType().GetMember(memberName);
}

if ((members == null) || (members.Length == 0))
{
return null;
}

return GetMemberValue(entity, members[0]);
}

public static void SetMemberValue(object entity, string memberName, object memberValue)
{
if ((entity == null) || (string.IsNullOrEmpty(memberName)))
{
return;
}

MemberInfo[] members;
members = entity.GetType().GetMember(memberName, BindingFlags.Public | BindingFlags.IgnoreCase | BindingFlags.Instance);
if ((members == null) || (members.Length == 0))
{
return;
}
if (members[0] is FieldInfo)
{
if (memberValue == DBNull.Value)
(members[0] as FieldInfo).SetValue(entity, null);
else
(members[0] as FieldInfo).SetValue(entity, memberValue);
}
else if (members[0] is PropertyInfo)
{
if (memberValue == DBNull.Value)
(members[0] as PropertyInfo).SetValue(entity, null, null);
else
(members[0] as PropertyInfo).SetValue(entity, memberValue,null);
}
}
}
}