使用数据库优先方法的 ChangeTracker 实现

Question

我们公司刚开始使用 EF，如果 guidance/advise 解决我们的问题，我将不胜感激。在这个项目中，我们使用 EF 6、Visual Studio 2015、数据库优先方法和 RESTful 服务（这是一个 RESTful API 使用 JSON 而不是通用的API，我们只需要审计日志方法是通用的即可）。我们需要实施审计并正在调查使用 ChangeTracker 功能。这个想法是制作一个可以接受任何实体的通用方法。这是我们目前所拥有的；

轮班结束API控制器：

public class EndOfShiftsController : ApiController
{
    private iSuiteEntities db = new iSuiteEntities();    
    // POST: api/EndOfShifts/post
    [Route("api/EndOfShift/post")]
    [ResponseType(typeof(EndOfShift))]
    public async Task<IHttpActionResult> PostEndOfShift_Post(EndOfShiftDto endOfShift)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        EndOfShift endofshift = new EndOfShift()
        {
            EndOfShiftID = endOfShift.EndOfShiftID,
            EndOfShiftDate = endOfShift.EndOfShiftDate,
            EquipmentID = endOfShift.EquipmentID,
            StartHours = endOfShift.StartHours,
            EndHours = endOfShift.EndHours,
            CreatedBy = endOfShift.CreatedBy,
            CreateDate = DateTime.Now,
            Active = true
        };

        try
        {
            if (!endOfShift.ToDelete)
            {
                if (EndOfShiftExists(endOfShift.EndOfShiftID))
                {
                    var update = db.EndOfShifts.Find(endOfShift.EndOfShiftID);
                    update.EndOfShiftDate = endofshift.EndOfShiftDate;
                    update.EquipmentID = endofshift.EquipmentID;
                    update.StartHours = endOfShift.StartHours;
                    update.EndHours = endOfShift.EndHours;
                    db.Entry(update).State = EntityState.Modified;

 //try calling the audit log method here/////////////////////////////////
                    AuditsController.GetAuditLogData(endofshift, endOfShift.EndOfShiftID, endOfShift.CreatedBy);
                    await db.SaveChangesAsync();
                }
                else
                {
                    db.EndOfShifts.Add(endofshift);
                    await db.SaveChangesAsync();
                }
            }
            else
            {
                EndOfShift delete = db.EndOfShifts.Find(endOfShift.EndOfShiftID);
                if (delete == null)
                {
                    return NotFound();
                }
                else
                {
                    delete.Active = false;
                    db.Entry(delete).State = EntityState.Modified;
                    await db.SaveChangesAsync();
                }
            }



            return Ok("Success");
        }   
        catch(Exception ex)
        {
            return Ok(ex.Message);
        }            
        //return CreatedAtRoute("DefaultApi", new { id = endOfShift.EndOfShiftID }, endOfShift);
    }

通用审核日志记录方法类似于：

public class AuditsController : ApiController
{
    private static iSuiteEntities dbContext = new iSuiteEntities();
    private static iSuiteEntities db = new iSuiteEntities();

    //write Audit log        
    public static async void GetAuditLogData<T>(T entity, int recID, int modByID) where T : new ()
    {
        try
        {                
            var changeTrack = dbContext.ChangeTracker.Entries().Where(p => p.State == EntityState.Added || p.State == EntityState.Deleted || p.State == EntityState.Modified);
            foreach (var entry in changeTrack)
            {
                if (entry.Entity != null)
                {
                    string entityName = string.Empty;
                    string state = string.Empty;
                    switch (entry.State)
                    {
                        case EntityState.Modified:
                            entityName = ObjectContext.GetObjectType(entry.Entity.GetType()).Name;
                            state = entry.State.ToString();
                            foreach (string prop in entry.OriginalValues.PropertyNames)
                            {
                                object currentValue = entry.CurrentValues[prop];
                                object originalValue = entry.OriginalValues[prop];
                                if (!currentValue.Equals(originalValue))
                                {
                                    Audit auditEntry = new Audit()
                                    {
                                        recordID = recID,
                                        tableName = entityName,
                                        fieldName = prop,
                                        oldValue = Convert.ToString(originalValue),
                                        editReason = "Update",
                                        modifiedBy = modByID,
                                        modifiedDate = DateTime.Now
                                    };

                                    db.Audits.Add(auditEntry);
                                    await db.SaveChangesAsync();
                                }
                            }
                            break;
                            //data addition is not required to be logged/////                            
                        case EntityState.Deleted:
                            entityName = ObjectContext.GetObjectType(entry.Entity.GetType()).Name;
                            state = entry.State.ToString();
                            foreach (string prop in entry.OriginalValues.PropertyNames)
                            {
                                Audit auditEntry = new Audit()
                                {
                                    recordID = recID,
                                    tableName = entityName,
                                    fieldName = prop,
                                    oldValue = Convert.ToString(entry.OriginalValues[prop]),
                                    editReason = "Delete",
                                    modifiedBy = modByID,
                                    modifiedDate = DateTime.Now
                                };

                                db.Audits.Add(auditEntry);
                                await db.SaveChangesAsync();                                    
                            }
                            break;
                        default:
                            break;
                    }
                }
            }
        }
        catch (Exception ex)
        {
            //handle exception here....
        }
    }

对于我们的审计日志要求来说，这是一个可行的选择吗？代码还没有经过测试，所以我相信我们也需要一些编码方面的指导。如果这不是实现我们目标的可行选择，您能否推荐一个可以使用数据库优先方法实现的选项？提前致谢！！

Answer 1

在对谷歌搜索的内容采取不同的方法后，我们找到了 this link，这为我们提供了解决问题的方法。留在这里希望能为其他开发人员节省一些时间:-)

使用数据库优先方法的 ChangeTracker 实现

ChangeTracker implementation with database first appraoch

ef-database-first

audit-logging

json-api