EntityFramework 6 实现软删除 全局过滤

准备工作

需要下载的包

EntityFrameworkEntityFramework.DynamicFilters

实施

接口

/// <summary> /// 软删除要实现的接口 /// </summary> public interface IDeletionWare { /// <summary> /// 是否已删除 /// </summary> bool IsDeleted { get; set; } /// <summary> /// 删除者id /// </summary> int? DeleterId { get; set; } /// <summary> /// 删除者姓名 /// </summary> string DeleterName { get; set; } /// <summary> /// 删除时间 /// </summary> DateTime? DeletionTime { get; set; } }

测试模型

/// <summary> /// 当前模型是需要软删除的 /// </summary> public class Product: IDeletionWare { public int Id { get; set; } public string Name { get; set; } public int? DeleterId {get; set;} public string DeleterName {get; set;} public DateTime? DeletionTime {get; set;} public bool IsDeleted { get; set; } } /// <summary> /// 不需要软删除 /// </summary> public class UselessThing { public int Id { get; set; } public string Name { get; set; } }

模拟session的类

public class Session { public static Session Current; static Session() { Current = new Session() { UserId = 1, Username = "神" }; } public int UserId { get; set; } public string Username { get; set; } }

准备创建DbContext

首先加入两个测试属性

public DbSet<Product> Products { get; set; } public DbSet<UselessThing> UserlessThings { get; set; }

重写SaveChanges, 这一步是执行软删除操作逻辑的

public override int SaveChanges() { // 筛选出实现IDeletionWare的模型 ChangeTracker.Entries<IDeletionWare>().ToList().ForEach(u =>SoftDelete(u)); return base.SaveChanges(); }

SoftDelete函数内容

private void SoftDelete(DbEntityEntry<IDeletionWare> entry) { /// 判断当前模型执行的操作 switch (entry.State) { // 防止模型字段被污染 case EntityState.Added: entry.Property(u => u.IsDeleted).CurrentValue = false; entry.Property(u=>u.DeletionTime).CurrentValue = null; entry.Property(u=>u.DeleterName).CurrentValue = null; entry.Property(u=>u.DeleterId).CurrentValue = null; break; // 防止模型字段被污染 case EntityState.Modified: entry.Property(u=>u.DeleterId).IsModified = false; entry.Property(u=>u.DeleterName).IsModified = false; entry.Property(u=>u.IsDeleted).IsModified = false; entry.Property(u=>u.DeletionTime).IsModified = false; break; case EntityState.Deleted: // 阻止默认删除操作 entry.State = EntityState.Unchanged; entry.Property(u=>u.DeleterId).IsModified = true; entry.Property(u=>u.DeleterName).IsModified = true; entry.Property(u=>u.IsDeleted).IsModified = true; entry.Property(u=>u.DeletionTime).IsModified = true; entry.Property(u=>u.IsDeleted).CurrentValue = true; entry.Property(u=>u.DeletionTime).CurrentValue = DateTime.Now; // 取出当前会话中的人员信息 entry.Property(u=>u.DeleterName).CurrentValue = Session.Current.Username; entry.Property(u=>u.DeleterId).CurrentValue = Session.Current.UserId; break; default: break; } }

重写OnModelCreating,添加filter, 这一步是为了添加一个能在查询时过滤软删除的数据的filter。

protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Filter("IsDeleted", (IDeletionWare d)=>d.IsDeleted, false); }

测试

创建dbContext对象, 并启用刚才添加的filter

var context = new TestDbContext(); context.EnableFilter("IsDeleted");

添加测试数据

var product = new Product { Name = "肥宅快乐水" }; var uselessThing = new UselessThing { Name = "..." }; context.Products.Add(product); context.UserlessThings.Add(uselessThing); context.SaveChanges();

结果

 

2018_08_18_17_59.25.jpg

2018_08_18_17_59.37.jpg

删除测试数据

var product = new Product { Id = 3 }; context.Products.Attach(product); context.Products.Remove(product); var thing = new UselessThing { Id = 3 }; context.UselessThings.Attach(thing); context.UselessThings.Remove(thing); context.SaveChanges();

结果

 

2018_08_18_18_00.52.jpg

2018_08_18_18_01.03.jpg

可以看出Products的数据还在，只不过IsDeleted变为true, 而UselessThings的数据被删除了。

查询Products的数据，看能不能查到

var a = context.Products.Where(u => u.Id == 3).FirstOrDefault();

结果

 

2018_08_18_18_03.47.jpg

可以看出filter起了作用,无法查到IsDeleted为true的数据。