Sequence contains more than one element
I'm having some issues with grabbing a list of type "RhsTruck" through Linq and getting them to display.
RhsTruck just has properites Make, Model, Serial etc... RhsCustomer has properties CustomerName, CustomerAddress, etc...
I keep getting the error "Sequence contains more than one element" (of type InvalidOperationException
). Any ideas? Am I approaching this the wrong way?
public RhsCustomer GetCustomer(string customerNumber)
{
using (RhsEbsDataContext context = new RhsEbsDataContext() )
{
RhsCustomer rc = (from x in context.custmasts
where x.kcustnum == customerNumber
select new RhsCustomer()
{
CustomerName = x.custname,
CustomerAddress = x.custadd + ", " + x.custcity
CustomerPhone = x.custphone,
CustomerFax = x.custfax
}).SingleOrDefault();
return rc;
}
}
public List<RhsTruck> GetEquipmentOwned(RhsCustomer cust)
{
using (RhsEbsDataContext context = new RhsEbsDataContext())
{
var trucks = (from m in context.mkpops
join c in context.custmasts
on m.kcustnum equals c.kcustnum
where m.kcustnum == cust.CustomerNumber
select new RhsTruck
{
Make = m.kmfg,
Model = m.kmodel,
Serial = m.kserialnum,
EquipID = m.kserialno1,
IsRental = false
}).ToList();
return trucks;
}
}
protected void Page_Load(object sender, EventArgs e)
{
string testCustNum = Page.Request.QueryString["custnum"].ToString();
RhsCustomerRepository rcrep = new RhsCustomerRepository();
RhsCustomer rc = rcrep.GetCustomer(testCustNum);
List<RhsTruck> trucks = rcrep.GetEquipmentOwned(rc);
// I want to display the List into a Gridview w/auto-generated columns
GridViewTrucks.DataSource = trucks;
GridViewTrucks.DataBind();
}
Solution 1:
The problem is that you are using SingleOrDefault
. This method will only succeed when the collections contains exactly 0 or 1 element. I believe you are looking for FirstOrDefault
which will succeed no matter how many elements are in the collection.
Solution 2:
SingleOrDefault
method throws an Exception
if there is more than one element in the sequence.
Apparently, your query in GetCustomer
is finding more than one match. So you will either need to refine your query or, most likely, check your data to see why you're getting multiple results for a given customer number.
Solution 3:
Use FirstOrDefault insted of SingleOrDefault..
SingleOrDefault returns a SINGLE element or null if no element is found. If 2 elements are found in your Enumerable then it throws the exception you are seeing
FirstOrDefault returns the FIRST element it finds or null if no element is found. so if there are 2 elements that match your predicate the second one is ignored
public int GetPackage(int id,int emp)
{
int getpackages=Convert.ToInt32(EmployerSubscriptionPackage.GetAllData().Where(x
=> x.SubscriptionPackageID ==`enter code here` id && x.EmployerID==emp ).FirstOrDefault().ID);
return getpackages;
}
1. var EmployerId = Convert.ToInt32(Session["EmployerId"]);
var getpackage = GetPackage(employerSubscription.ID, EmployerId);
Solution 4:
FYI you can also get this error if EF Migrations tries to run with no Db configured, for example in a Test Project.
Chased this for hours before I figured out that it was erroring on a query, but, not because of the query but because it was when Migrations kicked in to try to create the Db.