The mapping of interface member IDisplayOrder.ID is not supported.

Country 是Linq to sql 的一个实体类

如果我们按这个代码运行的话就会得到The mapping of interface member IDisplayOrder.ID is not supported.

注意看Exchange的代码

一个方法是先where 后FirstOrDefault 这个方法可以使用。而如果直接用FirstOrDefault 的话就会有错了

, IDisplayOrder
    {
        public ABC()
            : base()
        { }
        public ABC(WebDC dc)
            : base(dc)
        { }
        public void Exchange(int firstID,int secondID)
        {
            Table<T> table = DC.GetTable<T>();
           
            T first = table.Where(it=>it.ID==firstID).FirstOrDefault();
            int temp = first.DisplayOrder;
            T second = table.FirstOrDefault(it => it.ID ==secondID);
            first.DisplayOrder =  second.DisplayOrder;
            second.DisplayOrder = temp;
        }
    }

 IDisplayOrder
    {
         int ID { get; set; }
    
        int DisplayOrder { get; set; }
            
    }

    partial class Country:IDisplayOrder
    {
  
    }

 

 

WebDC dc = new WebDC(DataObject.connstr);
        ABC<Country> biz = new ABC<Country>(dc);
        biz.Exchange(20,21);
        dc.SubmitChanges();