为什么抛出错误：指定的强制转换无效？

Question

I used 'userid' in sql is int datatype and in backend(.cs) also used same int data type then why throwing this error:'specified cast is not valid'

var userRowsCustId = dsCustReg.Tables[0]
                              .AsEnumerable()
                              .Select(r => r.Field<int>("AccountNo"));

var allRowsCustId = dsAllTables.Tables[0]
                               .AsEnumerable()
                               .Select(r => r.Field<int>("UserId"));

IEnumerable<int> allIntersectingCustIds = userRowsCustId.Except(allRowsCustId);

if (allIntersectingCustIds.Any())
{
}

what is the solution for this error?

error throwing at r => r.Field<int>("AccountNo")

Answer 1

当我将其替换为double时，我接受了它。