2015-10-04-create-lambda-expressions-on-the-fly-in-c_005.cs

static void QueryByYear(string level) 
{ 
    GradeLevel year = (GradeLevel)Convert.ToInt32(level); 
    IEnumerable<Student> studentQuery = null; 
    
    switch (year) 
    { 
        case GradeLevel.FirstYear: 
            studentQuery = from student in students 
                where student.Year == GradeLevel.FirstYear 
                select student; 
            break; 
        case GradeLevel.SecondYear: 
            studentQuery = from student in students 
                where student.Year == GradeLevel.SecondYear 
                select student; 
            break;        
        case GradeLevel.ThirdYear: 
            studentQuery = from student in students 
                where student.Year == GradeLevel.ThirdYear 
                select student;
            break;        
        case GradeLevel.FourthYear: 
            studentQuery = from student in students 
                where student.Year == GradeLevel.FourthYear 
                select student; 
            break;         
        default: 
            break; 
    } 
    
    Console.WriteLine("The following students are at level {0}", year.ToString()); 
    
    foreach (Student name in studentQuery) 
    { 
        Console.WriteLine("{0}: {1}", name.LastName, name.ID); 
    } 
}