EF Audit-白红宇

EF Audit

阅读量：5034 次

发布时间：2019-06-12

本文共 9324 字，大约阅读时间需要 31 分钟。

需求比较复杂，真心不想多说。每次数据库操作都要记录原始值和新值到Audit表。而且其中一些外键字段不能存外键值而必须存其业务对应值，也就是其对应的导航属性的某个值

既然用了EF，哪个属性是普通属性，哪个是导航属性，哪个属性能对应到导航属性，都是可以得到的不是问题。但最终记录的是哪个导航属性的哪个值就不好说了，只能上配置信息。另外就是app规定不需要延迟加载，于是需要手动加载导航属性值

先定义一下配置信息相关类

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace EFAuditComponet{    public class AuditConfigItem    {        public string EntityTypeName { set; get; }        public string EntityPropertyName { set; get; }                public string TargetNavigationPropertyPath { set; get; }        public bool NeedToRecordAudit { set; get; }            }    public static class AuditConfigExtention    {        public static bool CheckContains(this List
      
        list,string entityTypeFullName, string propertyName)        {            var result = list.GetConfigItem(entityTypeFullName, propertyName);            if (result == null)                return false;            else                return true;        }        public static AuditConfigItem GetConfigItem(this List
       
         list, string entityTypeFullName, string propertyName)        {            return list.Find(p => p.EntityTypeName == entityTypeFullName && p.EntityPropertyName == propertyName);        }    }}

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没啥好说的，POCO+扩展方法，简单好用。需要一提的是TargetNavigationPropertyPath的格式，是属性名.属性名.属性名....属性名。前面的都是导航属性的属性名，最后是实际值的属性名。具体用法后面示例中有。

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace EFAuditComponet{    public class EFAuditConfig    {        public static List
      
        ConfigData = new List
       
        ();    }}

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将配置信息存于一个静态List中，写个类是为了方便将来扩展

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace EFAuditComponet{    public class AuditRecord    {        public string PropertyName { set; get; }        public string OldValue { set; get; }        public string NewValue { set; get; }    }}

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这个也没啥好说的，Audit记录POCO

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Data.Entity;using System.Data.Entity.Infrastructure;using System.Data.Objects;using System.Data.Metadata.Edm;using System.Collections;namespace EFAuditComponet{    public class EFAuditManager    {        public void GetNavigationProperty
      
       (DbContext context) where T : class        {            if (context == null)            {                throw new ArgumentNullException("context");            }            ObjectContext objContext = ((IObjectContextAdapter)context).ObjectContext;            var set = objContext.CreateObjectSet
       
        ();            var entitySet = set.EntitySet;            Console.WriteLine("类型名称:");            Console.WriteLine(entitySet.ElementType.FullName);            Console.WriteLine(entitySet.ElementType.Name);            Console.WriteLine("属性名称:");            foreach (var pro in entitySet.ElementType.Properties)            {                Console.WriteLine(pro.Name);            }            Console.WriteLine("导航属性名称:");            foreach (var pro in entitySet.ElementType.NavigationProperties)            {                Console.WriteLine(pro.Name);            }            Console.WriteLine("成员名称:");            foreach (var pro in entitySet.ElementType.Members)            {                Console.WriteLine(pro.Name);            }            Console.WriteLine("属性与对应导航属性:");            foreach (var pro in entitySet.ElementType.NavigationProperties)            {                foreach (var fpro in pro.GetDependentProperties())                {                    Console.WriteLine(fpro.Name + ":" + pro.ToEndMember.Name);                }            }            Console.ReadKey();        }        public List
        
          GetObjectDataAndIncludeDataByConfig
         
          (DbContext context, T objInstance) where T : class        {            List
          
            auditList = new List
           
            (); ObjectContext objContext = ((IObjectContextAdapter)context).ObjectContext; var set = objContext.CreateObjectSet
            
             (); var entitySet = set.EntitySet; Dictionary
             
               naviCollection = new Dictionary
              
               (); foreach (var pro in entitySet.ElementType.NavigationProperties) { foreach (var fpro in pro.GetDependentProperties()) { naviCollection.Add(fpro.Name, pro); } } foreach (var pro in entitySet.ElementType.Properties) { string propertyName = pro.Name; AuditConfigItem configItem = EFAuditConfig.ConfigData.GetConfigItem(entitySet.ElementType.Name, propertyName); if (configItem != null && !configItem.NeedToRecordAudit) { continue; } AuditRecord record = new AuditRecord(); DbEntityEntry
               
                 entry = Attach
                
                 (context, objInstance); //DbPropertyValues dbValues = entry.GetDatabaseValues(); object originalValue = entry.Property(propertyName).OriginalValue; object currentValue = entry.Property(propertyName).CurrentValue; if (configItem == null || string.IsNullOrEmpty(configItem.TargetNavigationPropertyPath)) { record.PropertyName = propertyName; record.OldValue = originalValue.ToString(); record.NewValue = currentValue.ToString(); } else { record.PropertyName = propertyName; entry.Property(propertyName).CurrentValue = originalValue; record.OldValue = LoadReferenceValue(context,entry, configItem.TargetNavigationPropertyPath); entry.Property(propertyName).CurrentValue = currentValue; record.NewValue = LoadReferenceValue(context,entry, configItem.TargetNavigationPropertyPath); } auditList.Add(record); } return auditList; } private string LoadReferenceValue(DbContext context,DbEntityEntry entry,string targetNavigationPropertyPath) { string returnValue = null; string[] propertyNames = targetNavigationPropertyPath.Split('.'); for (int i = 0; i < propertyNames.Length; i++) { if (i != propertyNames.Length - 1) { if (!entry.Reference(propertyNames[i]).IsLoaded) entry.Reference(propertyNames[i]).Load(); entry = context.Entry(entry.Reference(propertyNames[i]).CurrentValue); } else returnValue = entry.Property(propertyNames[i]).CurrentValue == null ? null : entry.Property(propertyNames[i]).CurrentValue.ToString(); } return returnValue; } public DbEntityEntry
                 
                   Attach
                  
                   (DbContext context, T obj) where T : class { if (context == null) { throw new ArgumentNullException("context"); } DbEntityEntry
                   
                     entry; try { entry =context.Entry
                    
                     (obj); entry.State = System.Data.EntityState.Modified; } catch { var set = ((IObjectContextAdapter)context).ObjectContext.CreateObjectSet
                     
                      (); var entitySet = set.EntitySet; string[] keyNames = entitySet.ElementType.KeyMembers.Select(k => k.Name).ToArray(); string precidate = string.Empty; foreach (string filter in keyNames) { precidate += "it." + filter + "=" + context.Entry
                      
                       (obj).Property(filter).CurrentValue.ToString(); } var entity = set.Where(precidate).First(); //context.ChangeTracker.Entries
                       
                        ().ToList().Remove(GetEntityKeyNames(context, pE)； entry = context.Entry
                        
                         (entity); entry.CurrentValues.SetValues(obj); } return entry; } }}

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这个是真正的核心类，提供了所有我们需要的方法。方法名乱起了，其实第一个方法教你如何获得普通属性，如何获得导航属性，如何获得普通属性与导航属性的对应。

可以对照代码看看结果图,用PatronIdentification对象做的示例：

GetObjectDataAndIncludeDataByConfig则是真正的能将一个对象与Context中的对象比较，并得到AduitRecord集合。

这是修改了一个查询得到的对象后进行比对得到结果：

using (BE50Beta_AdminEntities1 context = new BE50Beta_AdminEntities1())            {                PatronIdentification result = context.PatronIdentification.Where(p => p.IdentificatinNumber == "aaaa").First();                result.CountryID = 2;                result.IdentificatinNumber = "1234567";                EFAuditManager manager = new EFAuditManager();                List
      
        list = manager.GetObjectDataAndIncludeDataByConfig
       
        (context, result);                foreach (var record in list)                {                    Console.WriteLine(record.PropertyName + " OldValue:" + record.OldValue + " NewValue:" + record.NewValue);                }                Console.ReadKey();            }

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思路其实也很简单，遍历一个实体的普通属性，如果针对每一个属性,有一个配置信息存在且该配置信息的TargetNavigationPropertyPath不为空。那么就需要记录TargetNavigationPropertyPath所指的属性值而不是本身值

记录本身值无难度，难点在记录导航属性的值，可能会导航多次。

于是用了LoadReferenceValue，遍历TargetNavigationPropertyPath路径，在最后一个路径点去取出真正的值，之前只是将导航属性对象手动Load。

以下是模拟了有配置数据的情况，注意TargetNavigationPropertyPath的用法

EFAuditConfig.ConfigData.Add(new AuditConfigItem() { EntityTypeName = "PatronIdentification", EntityPropertyName = "CountryID", NeedToRecordAudit = true, TargetNavigationPropertyPath = "Country.CountryName" });            using (BE50Beta_AdminEntities1 context = new BE50Beta_AdminEntities1())            {                PatronIdentification result = context.PatronIdentification.Where(p => p.IdentificatinNumber == "aaaa").First();                result.CountryID = 2;                result.IdentificatinNumber = "1234567";                EFAuditManager manager = new EFAuditManager();                List
      
        list = manager.GetObjectDataAndIncludeDataByConfig
       
        (context, result);                foreach (var record in list)                {                    Console.WriteLine(record.PropertyName + " OldValue:" + record.OldValue + " NewValue:" + record.NewValue);                }                Console.ReadKey();            }

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可以看到CountryID被成功替换成CountryName

转载于:https://www.cnblogs.com/vincentsun1234/archive/2013/05/28/3102892.html

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