protected override void OnModelCreating(ModelBuilder modelBuilder)

{

    foreach (var entityType in modelBuilder.Model.GetEntityTypes())

    {

        // 1. Add the IsDeleted property

        entityType.GetOrAddProperty("IsDeleted", typeof(bool));

        // 2. Create the query filter

        var parameter = Expression.Parameter(entityType.ClrType);

        // 3. EF.Property<bool>(post, "IsDeleted")

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

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

        // 4. EF.Property<bool>(post, "IsDeleted") == false

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

        // 5. post => EF.Property<bool>(post, "IsDeleted") == false

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

        modelBuilder.Entity(entityType.ClrType).HasQueryFilter(lambda);

public class ProductInfo : EntityBase, ISoftDelete

{

    public string Title { get; set; }

    public decimal Amount { get; set; }

    public int Discount { get; set; }

    public int Inventory { get; set; }

    public DateTime DeletedDate { get; set; }

    public string DeletedUser { get; set; }

    public bool IsDeleted { get; set; }

    /// <summary>

    /// domain method

    /// </summary>

    /// <returns></returns>

    public decimal GetSaleAmount()

    {

        return Amount * Discount / ;

    }

}

public void Delete(TEntity item)

{

    if (item != null)

    {

        if (typeof(ISoftDelete).IsAssignableFrom(item.GetType()))

        {

            Db.Entry(item).State = EntityState.Modified;

            var delEntity = item as ISoftDelete;

            delEntity.DeletedDate = DateTime.Now;

            delEntity.IsDeleted = true;

        }

        else

        {

            //物理删除

            Db.Set<TEntity>().Attach(item as TEntity);

            Db.Entry(item).State = EntityState.Deleted;

            Db.Set<TEntity>().Remove(item as TEntity);

        }

        this.SaveChanges();

    }

}