How to search result set from a result set - vb.net

Question

I have a problem to search result from a result set.
I search order based on customer id and store in rs, then I want to search payment based on order id from rs and store in rs2.
This rs2 will then bind in datagridview.
But I found that rs2 will keep reassign the previous data once new data found, so the final result always show the one result which is the last result found. I try use Static rs2 but it still not work.
Hope some expert can provide solution. Thank you.
Private Sub BindCard()
Dim name As String = cboCreditType.Text
Dim db As New ConcertDataContext()
Dim rs = From o In db.orders Where (o.customer_id = MemberLogin.id)
Dim allOrders = From id In rs Select id.order_id
Dim rs2 = From o In db.payments
Where (name = "All" Or o.creditType = name) And
allOrders.Contains(o.order_id)
Select o.payment_id, o.total_payment, o.creditNumber, o.creditType, o.order_id
dgv.DataSource = rs2 'Error occurs here'
End Sub

Answer 1

You have correctly identified the problem in your code, the solution is pretty simple.
Remove the loop, extract a list of orderid to process and then use that list as a condition with Contains against the payments data
' First extract a list of all orders ID present in the orders selected
Dim allOrders = from id in rs select id.orderid
' Then use that list and select only the payments for those orders
rs2 = From o In db.payments
Where (name = "All" Or o.creditType = name) And
(allOrders.Contains(o.order_id))
Select o.payment_id, o.total_payment, o.creditNumber, o.creditType, o.order_id
If you don't need all the data in rs then you can replace the initial query with
Dim allOrders = From o In db.orders
Where (o.customer_id = MemberLogin.id)
Select o.order_Id