How do you filter a list based on matching items in another list? - linq

Question

I have an Organisation object
public class Organisation
{
OrgId {get....}
OrgName {get...}
AccountTypes { get....} //this is of type List<AccountType>
}
and an AccountType object
public class AccountType
{
AccountTypeId {get....}
AccountTypeName {get...}
}
I'm looking for a way to look through the existing Organisations List and remove AccountTypes from each organisation where the account types are not found in another list of AccountTypes (which would be a post back from a browser).
Would I do something like?
var foundOrgs = from org in orgs
where org.OrganisationId == Convert.ToInt32(hash["orgId"])
select org;
Organisation organisation = foundOrgs.ElementAt(0);
organisation.AccountTypes.Clear();
organisation.AccountTypes = // What goes here?
I'm looking to do a Linq query that will compare one list with another and return only those items where the AccountTypeIDs match, or are present.

Answer 1

You can use List<T>.RemoveAll:
// where accounts is IEnumerable<int>
organisation.AccountTypes.RemoveAll(at => !accounts.Contains(at.AccountTypeId));

Answer 2

EDITED CODE
//created account id list over here
var AccountTypeID = accountType.Select(x=>x. AccountTypeId);
//you code
var foundOrgs = from org in orgs
where org.OrganisationId == Convert.ToInt32(hash["orgId"])
select org;
Organisation organisation = foundOrgs.ElementAt(0);
organisation.AccountTypes.Clear();
//changes in code where you want to change -// What goes here?
List<AccountTypes> templist = organisation.AccountTypes;
organisation.AccountTypes =
from acc in templist
where !AccountTypeID.Conains(acc.AccountTypeId)
select acc).ToList();
EDIT
No sure but you can try out
var orgdata= from org in foundOrgs
select { OrgId =org.OrgId ,OrgName = org.OrgName ,
AccountTypes = ( from acc in org.AccountTypes
where !AccountTypeID.Conains(acc.AccountTypeId)
select acc) };
Try something like this
var ids = {1, 2, 3};
var query = from item in context.items
where !ids.Contains( item.id )
select item;
this will give you list of element which are not part of 1,2,3 i.e ids list , same you can apply in you code first find out which are not there and than remove it from the list
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