C # filter the IQueryable <T> set by date range,
You need to extend IQueryable <T>. parameters include a DateTime type attribute, start date, and end date.
public static class MyExtension { public static IQueryable<T> WhereDateRange<T>(this IQueryable<T> source, Expression<Func<T, DateTime>> getter, DateTime from, DateTime to) { Expression body = getter.Body; var predicate = Expression.Lambda<Func<T, bool>>( Expression.And(Expression.GreaterThanOrEqual(body, Expression.Constant(from)),Expression.LessThanOrEqual(body, Expression.Constant(to))), getter.Parameters ); return source.Where(predicate); } }
You can now filter the sets that meet a certain date range. For example:
class Program { static void Main(string[] args) { IEnumerable<Pet> pets = new List<Pet> { new Pet {Id=1,Birthday=new DateTime(2014,1,2) }, new Pet {Id=2,Birthday=new DateTime(2015,1,2) }, new Pet {Id=1,Birthday=new DateTime(2016,1,2) } }; var query = pets.AsQueryable().WhereDateRange<Pet>(t => t.Birthday,DateTime.Now.AddYears(-2), DateTime.Now.AddYears(-1)); foreach(var item in query) { Console.WriteLine(item.Birthday.ToShortDateString()); } } } public class Pet { public int Id { get; set; } public DateTime Birthday { get; set; } }