我有一个 ienumerable 实体的集合要添加到数据库中,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:
上传包含详细信息的文件,并将在一个表中创建主记录。文件中的详细信息将被添加到一个单独的表中,其中包含第一个表中自动生成的 masterId
。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现错误。错误是因为文件的内容。有些行没有输入值,最后一行不遵循其余行的格式,因为它显示了总行数。感谢大家的帮助!
最佳答案
@slawekwin 评论就是答案。但我认为有更好的解决方案,因为您的代码似乎迭代了 2 次:第一次生成新的 Enumerable(浪费内存),第二次将对象添加到上下文。
不妨在迭代每一行时直接添加对象。
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,然后将其解析为您的新对象。这是我更改的部分:
BillCycleYear = int.Parse(row.Field<string>("Bill Cycle").Substring(0, 4)),
BillCycleMonth = byte.Parse(row.Field<string>("Bill Cycle").Substring(4)),
关于c# - 如何将对象从 IEnumerable 集合添加到数据库?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/38988710/