c# – 如何从IEnumerable集合中将对象添加到数据库？

我有一组可以添加到数据库的可相关实体,但似乎需要进行一些转换.谁能指出我正确的方向？bool InsertDetails(DataTable detailTable, string fileName){using (SunseapEBTContext context = new SunseapEBTContext()...

我有一组可以添加到数据库的可相关实体,但似乎需要进行一些转换.谁能指出我正确的方向？

bool InsertDetails(DataTable detailTable, string fileName)
{
    using (SunseapEBTContext context = new SunseapEBTContext())
    {
        if (InsertMaster(fileName))//if creating master record successful
        {                    
            int masterId = GetSPReadingM(m => m.FileName == fileName).SPReadingMasterId; //get MasterID of file uploaded

             var details = detailTable.AsEnumerable().Select(row => new LeasingSPReadingDetailEntity()//new entity from datatable
             {
                //SPReadingId = row.Field<long>("ProductID"),

                        SPReadingMasterId = masterId,
                        BillCycleYear = int.Parse(row.Field<int>("Bill Cycle").ToString().Substring(0, 4)),
                        BillCycleMonth = byte.Parse(row.Field<byte>("Bill Cycle").ToString().Substring(4))

            });
            foreach(IEnumerable<LeasingSPReadingDetailEntity> detail  in details)
            {                       
                context.LeasingSPReadingDetailEntities.AddObject(detail);
            }
            context.SaveChanges();                    
        }
        return true;
    }
}

在foreach循环中,抛出异常

CS1503 Argument 1: cannot convert from ‘System.Collections.Generic.IEnumerable’ to ‘SunseapEBT.Domain.BillingModule.LeasingContract.Entity.LeasingSPReadingDetailEntity’

LeasingSPReadingDetailEntity类：

public class LeasingSPReadingDetailEntity
{
    public long SPReadingId { get; set; }
    public int SPReadingMasterId { get; set; }
    public int BillCycleYear { get; set; }
    public byte BillCycleMonth { get; set; }

}

更多信息：
将上载包含详细信息的文件,并在一个表中创建主记录.文件中的详细信息将使用第一个表中自动生成的masterId添加到单独的表中.问题是无法将详细信息添加到数据库中.

编辑：
我发现了为什么会出错.该错误是由于文件的内容.某些行没有输入值,最后一行没有遵循其余行的格式,因为它显示了总行数.谢谢大家的帮助！

解决方法:

@slawekwin评论是答案.但我认为有一个更好的解决方案,因为看起来你的代码迭代2x：1st生成新的Enumerable(浪费内存),2nd将对象添加到上下文.

当您迭代每一行时,也可以直接添加对象.

foreach(var row in detailTable.AsEnumerable())
{                       
    context.LeasingSPReadingDetailEntities.AddObject(
        new LeasingSPReadingDetailEntity()//new entity from datatable
        {
           //SPReadingId = row.Field<long>("ProductID"),

           SPReadingMasterId = masterId,
           BillCycleYear = int.Parse(row.Field<string>("Bill Cycle").Substring(0, 4)),
           BillCycleMonth = byte.Parse(row.Field<string>("Bill Cycle").Substring(4)),
           AccountNumber = row.Field<string>("Account No."),
           PeriodStart = row.Field<DateTime>("Period Start"),
           PeriodEnd = row.Field<DateTime>("Period End"),
           TownCouncil = row.Field<string>("Customer Name"),
           Service = row.Field<string>("Service Type"),
           Adjustment = row.Field<string>("Adjustment"),
           Block = row.Field<string>("Blk"),
           AddressLine1 = row.Field<string>("Adress Line 1"),
           AddressLine2 = row.Field<string>("Adress Line 2"),
           AddressLine3 = row.Field<string>("Postal Code"),
           Usage = row.Field<decimal>("Usage"),
           Rate = row.Field<decimal>("Rate"),
           Amount = row.Field<decimal>("Amount")
        }
    );
}

—编辑—

我不确定,但我可以猜测“Bill Cycle”字段既不是int也不是byte.因此,您应该将其作为字符串检索,然后将其解析为新对象.这是我改变的部分：

BillCycleYear = int.Parse(row.Field<string>("Bill Cycle").Substring(0, 4)),
BillCycleMonth = byte.Parse(row.Field<string>("Bill Cycle").Substring(4)),