LINQ Joining in C with multiple conditions

Question

I have a LINQ Joining statement in C  with multiple conditions   var possibleSegments        from epl in eventPotentialLegs     join sd in segmentDurations on          new                epl ITARequestID               epl ITASliceNumber               epl DepartAirportAfter               epl AirportId Origin               epl AirportId Destination                     equals          new                sd ITARequestId               sd SliceIndex               sd OriginAirport               sd DestinationAirport                where         epl DepartAirportAfter  gt  sd UTCDepartureTime          and          epl ArriveAirportBy  gt  sd UTCArrivalTime     select new PossibleSegments  ArrivalTime   sd arrivalTime      The joining does not work correctly   What am I doing wrong

User · Answer

If you need not equal object condition use cross join sequences   var query   from obj1 in set1 from obj2 in set2 where obj1 key1    obj2 key2  amp  amp  obj1 key3 contains obj2 key5      conditions

User · Answer

Your and should be a  amp  amp  in the where clause   where epl DepartAirportAfter  gt   sd UTCDepartureTime  and epl ArriveAirportBy  gt  sd UTCArrivalTime   should be   where epl DepartAirportAfter  gt   sd UTCDepartureTime   amp  amp  epl ArriveAirportBy  gt  sd UTCArrivalTime

User · Answer

As far as I know you can only join this way  var query   from obj i in set1 join obj j in set2 on      new          JoinProperty1   obj i SomeField1        JoinProperty2   obj i SomeField2        JoinProperty3   obj i SomeField3        JoinProperty4   obj i SomeField4            equals      new          JoinProperty1   obj j SomeOtherField1        JoinProperty2   obj j SomeOtherField2        JoinProperty3   obj j SomeOtherField3        JoinProperty4   obj j SomeOtherField4        The main requirements are  Property names  types and order in the anonymous objects you re joining on must match  You CAN T use ANDs  ORs  etc  in joins  Just object1 equals object2  More advanced stuff in this LinqPad example  class c1            public int someIntField      public string someStringField             class c2            public Int64 someInt64Property  get set       private object someField      public string someStringFunction   return someField ToString                void Main         var set1   new List lt c1 gt         var set2   new List lt c2 gt              var query   from obj i in set1     join obj j in set2 on          new                    JoinProperty1    Int64  obj i someIntField                  JoinProperty2   obj i someStringField                        equals          new                    JoinProperty1   obj j someInt64Property                  JoinProperty2   obj j someStringFunction                     select new  obj1   obj i  obj2   obj j      Addressing names and property order is straightforward  addressing types can be achieved via casting converting parsing calling methods etc  This might not always work with LINQ to EF or SQL or NHibernate  most method calls definitely won t work and will fail at run-time  so YMMV  Your Mileage May Vary   This is because they are copied to public read-only properties in the anonymous objects  so as long as your expression produces values of correct type the join property - you should be fine

[c#] LINQ Joining in C# with multiple conditions

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