entity framework不查数据库修改或排除指定字段集合通用方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.Data.Objects.DataClasses;
public class EFDBHelper
{

    #region 不查数据库修改信息
    /// <summary>
    /// 不查数据库修改信息
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="entity"></param>
    /// <param name="db"></param>
    /// <param name="updateFiledType"></param>
    /// <param name="fileds"></param>
    /// <returns></returns>
    public static int Update<T>(T entity, DataDBEntities db,
        EnumUpdateFiledType updateFiledType, params string[] fileds)
    {
        if (null == db || null == entity)
        { // 参数有误
            return 0;
        }
        Type _type = typeof(T);
        db.AttachTo(_type.Name, entity);
        if (null == fileds || fileds.Length == 0)
        { // 全字段操作
            db.ObjectStateManager.ChangeObjectState(entity, System.Data.EntityState.Modified);      // 手动设置为修改状态
        }
        else
        { // 部分字段操作
            var _stateEntry = db.ObjectStateManager.GetObjectStateEntry(entity);                    // 得到实体状态
            if (EnumUpdateFiledType.字段修改 == updateFiledType)
            { // 部分字段修改
                for (int i = 0; i < fileds.Length; i++)
                {
                    _stateEntry.SetModifiedProperty(fileds[i]);
                }
            }
            else
            { // 部分字段排除
                PropertyInfo[] _properties = _type.GetProperties(); // 得到类的所有属性
                foreach (PropertyInfo item in _properties)
                {
                    if ("EntityState" == item.Name || "EntityKey" == item.Name)
                    {
                        continue;
                    }
                    // 主键判断 [EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)] 根据特性判断主键
                    EdmScalarPropertyAttribute _edmScalarPropertyAttribute = 

Attribute.GetCustomAttribute(item, typeof(EdmScalarPropertyAttribute)) as EdmScalarPropertyAttribute;
                    if (null == _edmScalarPropertyAttribute || _edmScalarPropertyAttribute.EntityKeyProperty)
                    { // 为主键或者导航属性
                        continue;
                    }

                    bool _thisIsUpdateFiled = true;  // 是否为修改字段
                    for (int i = 0; i < fileds.Length; i++)
                    {
                        if (item.Name == fileds[i])
                        {
                            _thisIsUpdateFiled = false;
                            break;
                        }
                    }
                    if (_thisIsUpdateFiled)
                        _stateEntry.SetModifiedProperty(item.Name);
                }

            }
        }
        return db.SaveChanges();
    }

    /// <summary>
    /// 不查数据库修改信息
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="entity"></param>
    /// <param name="db"></param>
    /// <returns></returns>
    public static int Update<T>(T entity, DataDBEntities db)
    {
        if (null == db || null == entity)
        { // 参数有误
            return 0;
        }
        Type _type = typeof(T);
        db.AttachTo(_type.Name, entity);
        db.ObjectStateManager.ChangeObjectState(entity, System.Data.EntityState.Modified);      // 手动设置为修改状态
        return db.SaveChanges();
    }

    /// <summary>
    /// 不查数据库修改信息
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="entity"></param>
    /// <param name="updateFiledType"></param>
    /// <param name="fileds"></param>
    /// <returns></returns>
    public static int Update<T>(T entity, EnumUpdateFiledType updateFiledType, params string[] fileds)
    {
        if (null == entity)
        { // 参数有误
            return 0;
        }
        using (DataDBEntities db = new DataDBEntities())
        {
            Type _type = typeof(T);
            db.AttachTo(_type.Name, entity);
            if (null == fileds || fileds.Length == 0)
            { // 全字段操作
                db.ObjectStateManager.ChangeObjectState(entity, System.Data.EntityState.Modified);      // 手动设置为修改状态
            }
            else
            { // 部分字段操作
                var _stateEntry = db.ObjectStateManager.GetObjectStateEntry(entity);                    // 得到实体状态
                if (EnumUpdateFiledType.字段修改 == updateFiledType)
                { // 部分字段修改
                    for (int i = 0; i < fileds.Length; i++)
                    {
                        _stateEntry.SetModifiedProperty(fileds[i]);
                    }
                }
                else
                { // 部分字段排除
                    PropertyInfo[] _properties = _type.GetProperties(); // 得到类的所有属性

                    foreach (PropertyInfo item in _properties)
                    {
                        if ("EntityState" == item.Name || "EntityKey" == item.Name)
                        {
                            continue;
                        }
                        // 主键判断 [EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)] 根据特性判断主键
                        EdmScalarPropertyAttribute _edmScalarPropertyAttribute = 

Attribute.GetCustomAttribute(item, typeof(EdmScalarPropertyAttribute)) as EdmScalarPropertyAttribute;
                        if (null == _edmScalarPropertyAttribute || _edmScalarPropertyAttribute.EntityKeyProperty)
                        { // 为主键或者导航属性
                            continue;
                        }
                        bool _thisIsUpdateFiled = true;  // 是否为修改字段
                        for (int i = 0; i < fileds.Length; i++)
                        {
                            if (item.Name == fileds[i])
                            {
                                _thisIsUpdateFiled = false;
                                break;
                            }
                        }
                        if (_thisIsUpdateFiled)
                            _stateEntry.SetModifiedProperty(item.Name);
                    }

                }
            }
            return db.SaveChanges();
        }
    }

    /// <summary>
    /// 不查数据库修改信息
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="entity"></param>
    /// <returns></returns>
    public static int Update<T>(T entity)
    {
        if (null == entity)
        { // 参数有误
            return 0;
        }
        using (DataDBEntities db = new DataDBEntities())
        {
            Type _type = typeof(T);
            db.AttachTo(_type.Name, entity);
            db.ObjectStateManager.ChangeObjectState(entity, System.Data.EntityState.Modified);      // 手动设置为修改状态
            return db.SaveChanges();
        }
    }

    #endregion

}

#region 修改时字段处理枚举
/// <summary>
/// 修改时字段处理枚举
/// </summary>
public enum EnumUpdateFiledType
{
    字段修改 = 1,
    字段忽略 = 2
}
#endregion