ef 通过反射和表达式树配置全局过滤筛选器

1.软删除接口

public interface ISoftDelete
    {
        bool IsDeleted { get; set; }
    }

2.实体类实现

public class TestDeleted:ISoftDelete
    {
        public int Id { get; set; }

        public string Name { get; set; }
        public bool IsDeleted { get; set; }


    }

3.modelBuilder扩展类

public static class CustomModelBuilderExtensions
    {
        public static void AddSoftDeleted(this ModelBuilder builder)
        {
            var entityTypes = builder.Model.GetEntityTypes().Where(e => typeof(ISoftDelete).IsAssignableFrom(e.ClrType));
            foreach (var entityType in entityTypes)
            {
                var parameter = Expression.Parameter(entityType.ClrType);

                var propertyMethodInfo = typeof(EF).GetMethod("Property").MakeGenericMethod(typeof(bool));

                var isDeletedProperty = Expression.Call(propertyMethodInfo, parameter, Expression.Constant("IsDeleted"));

                BinaryExpression compareExpression = Expression.MakeBinary(ExpressionType.Equal, isDeletedProperty, Expression.Constant(false));

                var lambdaExpression = Expression.Lambda(compareExpression, parameter);

                builder.Entity(entityType.ClrType).HasQueryFilter(lambdaExpression);
            }
        }
    }

4.迁移数据库

5.在OnModelCreating方法中使用全局筛选方法

builder.AddSoftDeleted();

 6.综上所述,如果想要对一张表应用软删除的话,不是对实体类加IsDeleted字段再配置,而是让他直接实现ISoftDelete接口,这样配置更灵活