DDD Code First 迁移数据实现EF CORE的软删除，值对象迁移配置

感谢jeffcky大佬的博客：

entityframework core 2.0全局过滤 （hasqueryfilter） https://www.cnblogs.com/createmyself/p/8491058.html

什么是值对象

没有唯一的标识，固定不变的，表示一个具体的概念，用来描述一个东西的特征，代表是什么，使用时直接添加或替换，值对象在迁移时，会以字段的形式迁移到数据库中

软删除

定义删除的接口

         public interface isoftdelete
         {
            bool isdeleted { get; set; }
         }
     

创建模型实现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的扩展以及code first 迁移配置

    protected override void onmodelcreating(modelbuilder modelbuilder)
        {          
            //设置软删除
            foreach (var entitytype in modelbuilder.model.getentitytypes())
            {               
                var parameter = expression.parameter(entitytype.clrtype);
                //查询类上面是否有owned（值对象）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);
                }      
            }
        }
     

在这里需要过滤掉值对象的类，在值对象的类上面声明一个特性，通过该特性过滤掉该值对象， 如果该类是值对象就直接跳过，不过滤值对象ef core会给值对象附加一个isdeleted的字段，ef core执行中会报错，提示找不到该字段
owned是ef core 配置值对象的特性，可以去自定义特性，在每一个值对象上面声明，在onmodelcreating 过滤掉包含这个特性的类
最终实现的代码：

         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();

            headerresult> result = new headerresult>
            {
                issucceed = true,
                result = userdtolist,
                total = total
            };
            return result;
        }