EntityFramework將執行查詢的用戶傳遞給MSSQL

Question

我有一個MSSQL數據庫和一個帶有EntityFramework Core的ASP.NET MVC Core WebApi項目。

我有自定義表稱爲用戶和BlogPosts。 我想更新BlogPosts列「ModifiedById」每次它由用戶表中的Id更新。

我想爲這樣的操作使用SQL觸發器，但我找不到一種方法來傳遞用戶ID與每個查詢。缺點是我需要每個表一個觸發器。

有沒有更好的解決方案？

是的，有:)如所提出的，最好的選擇是覆蓋DbContext的SaveChanges（）方法。

關於， p。

Answer 1

我通常通過繼承和覆蓋來實現SaveChanges（） - 這與Code First一起工作，並且必須手動將審計字段添加到每個類。

public abstract class TrackedEntity 
{ 
    public DateTime CreatedDate { get; set; } 
    public DateTime ModifiedDate { get; set; } 
    public string ModifiedBy { get; set; } 
} 


public class SomeOtherClass : TrackedEntity 
{ 
    // Class specific properties here 
} 

，然後在你的DbContext

private User _loggedOnUser 

    public override int SaveChanges() 
    { 
     var timestamp = DateTime.Now; 

     // First look at new items these need created date adding 
     var addedEntities = ChangeTracker.Entries().Where(x => x.State == EntityState.Added).Select(x => x.Entity); 

     foreach (var addition in addedEntities) 
     { 
      var entity = addition as TrackedEntity; 

      if (entity != null) 
      { 
       entity.CreatedDate = timestamp; 
       entity.ModifiedDate = timestamp; 
       entity.ModifiedBy = _loggedOnUser; 
      } 
     } 

     // Next look at modified entries 
     var modifiedEntities = ChangeTracker.Entries().Where(x => x.State == EntityState.Modified || x.State == EntityState.Deleted); 

     foreach (var update in modifiedEntities) 
     { 
      // Only check tracked entities if modified 
      if (update.State == EntityState.Modified) 
      { 
       var tracked = update.Entity as TrackedEntity; 

       if (tracked != null) 
       { 
        tracked.ModifiedDate = timestamp; 
        tracked.ModifiedBy = _loggedOnUser; 
       } 
      } 
     } 
    } 

，並得到用戶

private void GetUser() 
    { 

     string user = string.Empty; 

     // if we have an http context, lets try it first 
     if (System.Web.HttpContext.Current != null) 
     { 
      if (System.Web.HttpContext.Current.User.Identity != null && System.Web.HttpContext.Current.User.Identity.IsAuthenticated) 
       user = System.Web.HttpContext.Current.User.Identity.Name; 
     } 

     if (user == null) 
      user = System.Threading.Thread.CurrentPrincipal.Identity.Name; 

     _loggedOnUser = this.Users.SingleOrDefault(x => x.Username == user); 
    } 

Answer 2

如果您使用的WebMatrix：

using WebMatrix.WebData; 
//... 
BlogPost bp = new BlogPost() 
{ 
    // other properties 
    ModifiedById = WebSecurity.CurrentUserId, 
} 

Answer 3

感謝@Igor和@ STE-FU。

至於建議我已經被覆蓋的的SaveChanges如下：

public override int SaveChanges() 
    { 
     var timeStamp = DateTime.UtcNow; 
     var userId = this.GetAuthenticatedUser(); 

     this.HandleAddedEntities(userId, timeStamp); 
     this.HandleModifiedEntities(userId, timeStamp); 

     return base.SaveChanges(); 
    } 
    private void HandleAddedEntities(Guid userId, DateTime timeStamp) 
    { 
     var entities = ChangeTracker.Entries() 
         .Where(x => x.Entity is IAddedEntity && 
            x.State == EntityState.Added) 
         .Select(x => x.Entity as IAddedEntity); 

     foreach (var e in entities) 
     { 
      e.CreatedById = userId; 
      e.CreatedOn = timeStamp; 
     } 
    } 

    private void HandleModifiedEntities(Guid userId, DateTime timeStamp) 
    { 
     var entities = ChangeTracker.Entries() 
         .Where(x => x.Entity is IModifiedEntity && 
            (x.State == EntityState.Added || 
             x.State == EntityState.Modified)) 
         .Select(x => x.Entity as IModifiedEntity); 

     foreach (var e in entities) 
     { 
      e.ModifiedById = userId; 
      e.ModifiedOn = timeStamp; 
     } 
    } 

正如我所使用的接口，因爲這樣我願意接受其他「通用觸發」在需要時的評論中指出。

感謝球員們的額外快速反應。