Group by some property in a class constructor.

classGroupBy.cs

public class BusinessHours {
  public DateTime openAt { get; private set; }
  public DateTime closeAt { get; private set; }
  public BusinessHours(DateTime openAt, DateTime closeAt) {
    this.openAt = openAt;
    this.closeAt = closeAt;
  }
}

public class GroceryStore<T> where T : Grocery {
  public String storeName { get; set; }
  public String storeLocation { get; set; }
  public BusinessHours storeBusinessHours { get; set; }
  // TODO: Contructor.
}

public abstract class Grocery {
  public String itemName { get; set; }
  public float itemPrice { get; set; }
  public DateTime itemExpiryDate { get; set; }
}

public class Food : Grocery {}

public class DailyUse : Grocery {}