Log寫得好，晚上睡覺睡得好
因為目前都在用Entity Framework來處理DB，想很久Log要怎麼寫比較好
在每個Method SaveChange前多一行寫Log的動作?
這樣做非常累也不是一勞永逸的方法，只要有新的CRUD，你都必須要每個都加上去
那麼新進人員進來，不知道要加這一行來寫Log不就糗了
所以我目前想到最好的方式就是覆寫EF的SaveChange的方法
加在裡面的好處就是，只要你是用EF來CRUD，我就一定會處理的到
新進人員也不需要處理寫Log這一塊，因為已經包在底層了
所以開了3個資料表
LogEntityRef 是存放什麼資料表需要寫入Log
LogEntityField 是存放資料表的那些欄位需要寫入Log
LogEntityValue 是寫入Log的資料
三個資料表可參考下圖
那麼怎麼覆寫EF的SaveChange呢，創建一個新的Class要與EF的名稱同名
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Data.Entity.Core.Metadata.Edm;
using System.Data.Entity.Core.Objects;
using System.Data.Entity.Infrastructure;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace SportBook.Entity
{
public partial class sbkEntities : DbContext
{
private string sysName = "SYSTEM";
public override Task<int> SaveChangesAsync(CancellationToken cancellationToken = default(CancellationToken))
{
SetValuesOnBeforeSaveChanges();
return PrivateSaveChangesAsync(cancellationToken);
}
public override Task<int> SaveChangesAsync()
{
SetValuesOnBeforeSaveChanges();
return PrivateSaveChangesAsync(CancellationToken.None);
}
public override int SaveChanges()
{
SetValuesOnBeforeSaveChanges();
return PrivateSaveChangesAsync(CancellationToken.None).Result;
}
/// <summary>
/// SaveChange之前把必要欄位寫入
/// </summary>
private void SetValuesOnBeforeSaveChanges()
{
var trackerEntries = this.ChangeTracker.Entries()
.Where(x => x.State == EntityState.Modified || x.State == EntityState.Added).ToList();
foreach (var entry in trackerEntries)
{
switch (entry.State)
{
case EntityState.Modified:
entry.CurrentValues.SetValues(new { UserUpdated = sysName, DateUpdated = DateTime.UtcNow });
break;
case EntityState.Added:
entry.CurrentValues.SetValues(new { UserCreated = sysName, DateCreated = DateTime.UtcNow });
break;
}
}
}
/// <summary>
/// SaveChange之後開始寫Log
/// </summary>
/// <param name="cancellationToken"></param>
/// <returns></returns>
private async Task<int> PrivateSaveChangesAsync(CancellationToken cancellationToken)
{
ObjectContext context = ((IObjectContextAdapter)this).ObjectContext;
await context.SaveChangesAsync(SaveOptions.DetectChangesBeforeSave, cancellationToken).ConfigureAwait(false);
var trackerEntries = this.ChangeTracker.Entries()
.Where(x => x.State == EntityState.Modified || x.State == EntityState.Added).ToList();
var LogValue = new List<Entity.LogEntityValue>();
foreach (var entry in trackerEntries)
{
var entityName = entry.Entity.GetType().Name;
//判斷entityName是否需要寫入Log
var LogEntityRef = this.LogEntityRef.AsNoTracking().Where(x => x.Code == entityName).FirstOrDefault();
if (LogEntityRef != null)
{
//取出Table那些欄位需要更新
var LogEntityField = this.LogEntityField.AsNoTracking().Where(x => x.LogEntityRefId == LogEntityRef.Id)
.Select(x => new
{
Id = x.Id,
FieldName = x.FieldName
}).ToList();
var primaryKey = entry.CurrentValues.GetValue<object>("Id");
foreach (var logfield in LogEntityField)
{
var originalValue = (entry.State == EntityState.Added) ? string.Empty : entry.OriginalValues.GetValue<object>(logfield.FieldName);
var currentValue = entry.CurrentValues.GetValue<object>(logfield.FieldName);
if (entry.State == EntityState.Modified)
{
if (originalValue.ToString() == currentValue.ToString())
continue;
}
LogValue.Add(new Entity.LogEntityValue
{
DateCreated = DateTime.UtcNow,
UserCreated = sysName,
LogEntityRefId = LogEntityRef.Id,
RefObjectId = (int?)primaryKey,
LogEntityFieldId = logfield.Id,
OldValue = originalValue.ToString(),
NewValue = currentValue.ToString()
});
}
}
}
context.AcceptAllChanges();
LogEntityValue.AddRange(LogValue);
int result = await context.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
return result;
}
}
}
以上就是寫Log的原始碼
