DDD Code First 遷移數據實現EF CORE的軟刪除，值對象遷移配置

感謝Jeffcky大佬的博客：

EntityFramework Core 2.0全局過濾 （HasQueryFilter） https://www.cnblogs.com/CreateMyself/p/8491058.html

什么是值對象

沒有唯一的標識，固定不變的，表示一個具體的概念，用來描述一個東西的特征，代表是什么，使用時直接添加或替換，值對象在遷移時，會以字段的形式遷移到數據庫中

軟刪除

定義刪除的接口

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

創建模型實現ISoftDelete接口

       public class UserInfo : IAggregationRoot, ISoftDelete
        {       
          public Guid Id { get; set; }
          public string UserName { get; private set; }
          public string UserPassword { get; private set; }
          public string UserPhone { get; private set; }
          public Address Address { get; private set; }
          public bool IsDeleted { get; set; }
        }
        [Owned]
        public class Address:IValueObject
        { 
          public string Province { get;private set; }
          public string City { get; private set; }
          public string County { get; private set; }
          public string AddressDetails { get; private set; }    
        }
     

Lamda的擴展以及Code First 遷移配置

    protected override void OnModelCreating(ModelBuilder modelBuilder)
        {          
            //設置軟刪除
            foreach (var entityType in modelBuilder.Model.GetEntityTypes())
            {               
                var parameter = Expression.Parameter(entityType.ClrType);
                //查詢類上面是否有Owned（值對象）的特性
                var ownedModelType = parameter.Type;
                var ownedAttribute = Attribute.GetCustomAttribute(ownedModelType, typeof(OwnedAttribute));
                if (ownedAttribute == null)
                {
                    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 lambda = Expression.Lambda(compareExpression, parameter);
                    modelBuilder.Entity(entityType.ClrType).HasQueryFilter(lambda);
                }      
            }
        }
     

在這里需要過濾掉值對象的類，在值對象的類上面聲明一個特性，通過該特性過濾掉該值對象， 如果該類是值對象就直接跳過，不過濾值對象EF CORE會給值對象附加一個IsDeleted的字段，EF CORE執行中會報錯，提示找不到該字段
Owned是EF CORE 配置值對象的特性，可以去自定義特性，在每一個值對象上面聲明，在OnModelCreating 過濾掉包含這個特性的類
最終實現的代碼：

         public async Task
  
  
  
          
           
   
   
   >> GetUserList(SearchUserDto input)
         {
            Expression
   
   
   
           
             > where = e => e.IsDisable == false; if (!string.IsNullOrEmpty(input.SearchName)) { where = where.And(e => e.UserName.Contains(input.SearchName)); } 
            
        if (!string.IsNullOrEmpty(input.SearchPwd))
        {
            where = where.And(e => e.UserPhone.Contains(input.SearchPwd));
        }
     
        var userList = await _userRepository.LoadEntityListAsync(where, e => e.UserName, "asc", input.PageIndex, input.Pagesize);
        var total = await _userRepository.GetEntitiesCountAsync(where);
        var userDtoList = userList.MapToList<UserInfo, UserDto>();

        HeaderResult<List<UserDto>> result = new HeaderResult<List<UserDto>>
        {
            IsSucceed = true,
            Result = userDtoList,
            Total = total
        };
        return result;
    }
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