我试图在EF Core 2.0中开始软删除行为。
public interface ISoftDeleteModel { bool IsDeleted { get; set; } }
创建适当的列和软删除可以正常工作,但不能从DbContext过滤实体。
我想在上下文中使用查询过滤,但遇到问题。
protected override void OnModelCreating(ModelBuilder modelBuilder) { Type entityType; // ^^^ it contains type of entity, eg. Blog, Post, etc. using // modelBuilder.Model.GetEntityTypes().First().Name and converting to Type var entity = modelBuilder.Entity(entityType); if(entityType.GetInterface("ISoftDeleteModel") != null) { // ??? how to access IsDeleted property ??? entity.HasQueryFilter(x => !x.IsDeleted); } }
问题很简单-如何访问IsDeleted属性?
如果我知道实体的类型,例如 发布并发布实现的ISoftDeleteModel,我将能够做到这一点:
protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Post>().HasQueryFilter(x => !x.IsDeleted); }
但是我不知道类型。我正在尝试实现简单的事情-实现该接口的所有模型都将被自动过滤。我想念什么吗?
无法测试确切的API,但是一般的方法是创建一个受约束的泛型方法并通过反射进行调用:
public static class EFFilterExtensions { public static void SetSoftDeleteFilter(this ModelBuilder modelBuilder, Type entityType) { SetSoftDeleteFilterMethod.MakeGenericMethod(entityType) .Invoke(null, new object[] { modelBuilder }); } static readonly MethodInfo SetSoftDeleteFilterMethod = typeof(EFFilterExtensions) .GetMethods(BindingFlags.Public | BindingFlags.Static) .Single(t => t.IsGenericMethod && t.Name == "SetSoftDeleteFilter"); public static void SetSoftDeleteFilter<TEntity>(this ModelBuilder modelBuilder) where TEntity : class, ISoftDeleteModel { modelBuilder.Entity<TEntity>().HasQueryFilter(x => !x.IsDeleted); } }
现在,您可以在您的内部使用类似的内容OnModelCreating:
OnModelCreating
foreach (var type in modelBuilder.Model.GetEntityTypes()) { if (typeof(ISoftDeleteModel).IsAssignableFrom(type.ClrType)) modelBuilder.SetSoftDeleteFilter(type.ClrType); }