将 SaveChange 中的旧值和新值保存为 DbEntityEntry.Entity 以进行审核

Question

如您所知，我们可以在 SaveChange() 中审核对象，但我对已修改和已删除的实体存在一些问题，如下所示，

首先，我使用 Audit.Net（这使用起来非常简单）来审核我的对象，下面的方法应该进行审核：

 private int SaveAuditRecord(DbEntityEntry dbEntry, string userGUID)
    {
        Logging.Log(LoggingMode.Error, "Saving Audid Entry{0}....", dbEntry.ToString());
        DateTime changeTime = DateTime.UtcNow;
        TableAttribute tableAttr = dbEntry.Entity.GetType().GetCustomAttributes(typeof(TableAttribute), true).SingleOrDefault() as TableAttribute;
        string tableName = tableAttr != null ? tableAttr.Name : dbEntry.Entity.GetType().Name;
        Logging.Log(LoggingMode.Error, "TableName Retrived {0}...", tableName);
        switch (dbEntry.State)
        {
            case System.Data.Entity.EntityState.Added:
                int result = base.SaveChanges(); 
                AuditNet.AuditMonoAction("Add " + tableName, userGUID, dbEntry.Entity);
                return result;
            case System.Data.Entity.EntityState.Deleted:
                AuditNet.AuditMonoAction("Delete " + tableName, userGUID, dbEntry.Entity);
                break;
            case System.Data.Entity.EntityState.Modified:
                int modifiedResult = 0;
                var primaryKey = GetPrimaryKeyValue(dbEntry);
                modifiedResult = base.SaveChanges(); 
                object entity2Audit = dbEntry.Entity;//Hold the current entity here and change it in below Audit using block
                using (var audit = Audit.Core.AuditScope.Create("Edit " + tableName, () => dbEntry.Entity))
                { 
                    audit.SetCustomField("UserGUID", userGUID, false);  
                    foreach (var prop in dbEntry.OriginalValues.PropertyNames)
                    {
                        var originalValue = dbEntry.OriginalValues[prop].ToString();
                        var currentValue = dbEntry.CurrentValues[prop].ToString();
                        if (originalValue != currentValue)
                            Logging.Log(LoggingMode.Error, "Prop {0} get originalValue :{1} , currentValue:{2}", prop, originalValue, currentValue);
                    } 
                }
                return modifiedResult;
            default:
                break;
        }
        return base.SaveChanges();
    }

1- 对于添加状态，没有问题，因为我正在审核 dbEntry.Entity，我认为它始终包含当前值。

2- 对于 Delete 和 Modify 有一些问题，

删除：我认为我正在审核 dbEntry.Entity，它正在寻找当前值并引发异常：

CurrentValues cannot be used for entities in the Deleted state.

修改：总是OldValue和NewValue总是和我上面提到的CurrentValue一样

所以我的主要问题是如何像 dbEntry.Entity 那样进行删除和修改？

P.S: 在 Using 块中，我们可以更改审计对象以将 NewValue 设置为 Audit.Net 提到的。

更新1：

即使使用此代码，旧值和新值始终相同：

 int modRes = 0;
                object entity2Audit = dbEntry.Entity;//Hold the current entity here and change it in below Audit using block
                DbEntityEntry dbEntryTemp = dbEntry;
                foreach (var prop in dbEntryTemp.OriginalValues.PropertyNames)
                {
                    var originalValue = dbEntry.OriginalValues[prop].ToString();
                    var currentValue = dbEntry.CurrentValues[prop].ToString();
                    if (originalValue != currentValue)
                    {
                        Logging.Log(LoggingMode.Error, "Prop11 {0} get originalValue :{1} , currentValue:{2}", prop, originalValue, currentValue);
                        dbEntryTemp.CurrentValues[prop] = dbEntryTemp.OriginalValues[prop] = originalValue;
                    }
                } 
                object en = dbEntryTemp.Entity;
                using (var audit = Audit.Core.AuditScope.Create("Edit " + tableName, () => en))
                {
                    modRes = base.SaveChanges();
                    audit.SetCustomField("UserGUID", userGUID, false);
                    audit.SetCustomField("NewValue", dbEntry.Entity, false);
                    audit.SetCustomField("OldValue", en, false);
                    en = dbEntry.Entity;
                }

Answer 1

首先我要感谢 thepirat000 制作了 Audit.Net 库，这是一个非常好的审计库，有很多选项，正如他在 GitHub

中提到的

但是关于我的问题，这是我第一次覆盖 SaveChange() 并且我也不知道 DbEntityEntry 对象，但是解决方案看起来很有趣，只需要转换 CurrentValues 和 OriginalValues 到 Object()，在修改的情况下，我通过 dbEntry.OriginalValues.ToObject() 获取旧值并在 Audit.Net 范围内用 dbEntry.CurrentValues.ToObject() 更改它，即全部。

  Logging.Log(LoggingMode.Prompt, "Saving Audid Entry{0}....", dbEntry.ToString()); 
        TableAttribute tableAttr = dbEntry.Entity.GetType().GetCustomAttributes(typeof(TableAttribute), true).SingleOrDefault() as TableAttribute;
        string tableName = tableAttr != null ? tableAttr.Name : dbEntry.Entity.GetType().Name;
        Logging.Log(LoggingMode.Prompt, "TableName Retrived {0}...", tableName);
        switch (dbEntry.State)
        {
            case System.Data.Entity.EntityState.Added:
                int result = base.SaveChanges();
                object addedObj = dbEntry.Entity;
                using (var audit = Audit.Core.AuditScope.Create("Add " + tableName, () =>addedObj ))
                {
                    audit.SetCustomField("UserGUID", userGUID);
                    addedObj = null;
                } 
                return result;
            case System.Data.Entity.EntityState.Deleted:
                object deletedObj = dbEntry.Entity;
                using (var audit = Audit.Core.AuditScope.Create("Delete " + tableName, () => deletedObj))
                {
                    audit.SetCustomField("UserGUID", userGUID);
                    deletedObj = null;
                }  
                break;
            case System.Data.Entity.EntityState.Modified: 
                object en = dbEntry.OriginalValues.ToObject();
                using (var audit = Audit.Core.AuditScope.Create("Edit " + tableName, () => en))
                {
                    audit.SetCustomField("UserGUID", userGUID);
                    en = dbEntry.CurrentValues.ToObject();
                }
                break;
            default:
                break;
        }
        return base.SaveChanges();