Where IN clause in LINQ

Question

How to make a where in clause similar to one in SQL Server   I made one by myself but can anyone please improve this       public List lt State gt  Wherein string listofcountrycodes                string   countrycode   null          countrycode   listofcountrycodes Split               List lt State gt  statelist   new List lt State gt              for  int i   0  i  lt  countrycode Length  i                           states AddRange                   from states in  objdatasources StateList                    where states CountryCode    countrycode i  ToString                    select new State                                        StateName    states StateName                                                             return  states

User · Accepted Answer

This expression should do what you want to achieve   dataSource StateList Where s   gt  countryCodes Contains s CountryCode

User · Answer

public List lt Requirement gt  listInquiryLogged         using  DataClassesDataContext dt   new DataClassesDataContext System Configuration ConfigurationManager ConnectionStrings  ApplicationServices   ConnectionString                 var inq   new int    1683 1684 1685 1686 1687 1688 1688 1689 1690 1691 1692 1693           var result   from Q in dt Requirements                      where inq Contains Q ID                       orderby Q Description                      select Q           return result ToList lt Requirement gt

User · Answer

This will translate to a where in clause in Linq to SQL     var myInClause   new string     One    Two    Three     var results   from x in MyTable               where myInClause Contains x SomeColumn                select x     OR var results   MyTable Where x   gt  myInClause Contains x SomeColumn      In the case of your query  you could do something like this     var results   from states in  objectdatasource StateList                 where listofcountrycodes Contains states CountryCode                select new State                                   StateName   states StateName                     OR var results    objectdatasource StateList                      Where s   gt  listofcountrycodes Contains s CountryCode                      Select s   gt  new State   StateName   s StateName

User · Answer

This little bit different idea  But it will useful to you  I have used sub query to inside the linq main query   Problem   Let say we have document table  Schema as follows schema   document name version auther modifieddate  composite Keys   name version  So we need to get latest versions of all documents   soloution   var result    from t in Context document                           where   from tt in Context document where t Name    tt Name                                 orderby tt Version descending select new  Vesion tt Version   FirstOrDefault    Vesion Contains t Version                            select t  ToList

User · Answer

from state in  objedatasource StateList   where listofcountrycodes Contains state CountryCode  select state

User · Answer

The  IN  clause is built into linq via the  Contains   method   For example  to get all People whose  States s are  NY  or  FL    using  DataContext dc   new DataContext  connectionstring          List lt string gt  states   new List lt string gt     NY    FL        List lt Person gt  list    from p in dc GetTable lt Person gt    where states Contains p State  select p  ToList

User · Answer

I like it as an extension method   public static bool In lt T gt  this T source  params T   list        return list Contains source       Now you call   var states    objdatasources StateList   Where s   gt  s In countrycodes      You can pass individual values too   var states   tooManyStates Where s   gt  s In  x    y    z       Feels more natural and closer to sql

User · Answer

public List lt State gt  GetcountryCodeStates List lt string gt  countryCodes        List lt State gt  states   new List lt State gt         states    from a in  objdatasources StateList AsEnumerable       where countryCodes Any c   gt  c Contains a CountryCode       select a  ToList        return states

[c#] Where IN clause in LINQ

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