[Solved]-How to combine two lists with different properties based on a condition in C#-LINQ,C#

you can use linq to join both data lists. more about it here.

class plan {
  public int plancode { get; set; }
  public string planshortname { get; set; }
}

class division {
  public int divisioncode { get; set; }
  public string divisionname { get; set; }
}

class divisionassignment {
  public int plancode { get; set; }
  public list<division> divisions { get; set; }
}

public static void joinexample() {
  // do your deserialization stuff here
  list<plan> plans = ...;
  list<divisionassignment> assignments = ...;

  // join the data
  var query = from plan in plans
              join assignment in assignments on plan.plancode equals assignment.plancode
              select new { plancode = plan.plancode, divisions = assignment.divisions };

  // reach the joined data
  foreach (var plandivision in query) {
    ... = plandivision.plancode;
    ... = plandivision.divisions;
    ...
  }
}