EF - Subtract Two Dates

CSharp · Console

/Program.cs

// @nuget: EntityFramework
// @nuget: Z.EntityFramework.Extensions

using System;
using System.Data.Entity;
using System.Linq;
using System.Collections.Generic;
					
public class Program
{
	public static void Main()
	{
		// Insert data
		InsertData();
		
		using (var context = new EntityContext())
		{	
			int noOfDays = 30;
    		DateTime oldDate = DateTime.Now.Subtract(new TimeSpan(noOfDays, 0, 0, 0, 0));

    		var invoices = context.Invoices
        		.Where(i => i.Date > oldDate)
        		.ToList();
			
			DisplayData(invoices);
		}
	}
	
	public static void InsertData()
	{
		using (var context = new EntityContext())
		{
			context.BulkInsert(CustomerData());
			context.BulkInsert(InvoiceData());
			context.BulkInsert(ItemData());
		}
	}
	
	public static List<Customer> CustomerData() 
	{
		List<Customer>  list = new List<Customer>()
		{
			new Customer() { Name ="John"},
			new Customer() { Name ="Andy"},
			new Customer() { Name ="Mark"}
		};
		
		return list;
	}
	
	public static List<Invoice> InvoiceData()
	{
		List<Invoice> list = new List<Invoice>()
		{
			new Invoice() { Date = DateTime.Now.AddDays(-107), CustomerID = 1},
			new Invoice() { Date = DateTime.Now.AddDays(-5), CustomerID = 1},
			new Invoice() { Date = DateTime.Now.AddDays(-3), CustomerID = 1},
			new Invoice() { Date = DateTime.Now.AddDays(-105), CustomerID = 2},
			new Invoice() { Date = DateTime.Now.AddDays(-59), CustomerID = 3},
			new Invoice() { Date = DateTime.Now.AddDays(-25), CustomerID = 3},
		};
	
		return list;
	}
	public static List<Item> ItemData()
	{
		List<Item> list = new List<Item>()
		{
			new Item() { Name = "Item 1", InvoiceID = 1},
			new Item() { Name = "Item 2", InvoiceID = 1},
			new Item() { Name = "Item 3", InvoiceID = 1},
			new Item() { Name = "Item 10", InvoiceID = 2},
			new Item() { Name = "Item 5", InvoiceID = 2},
			new Item() { Name = "Item 11", InvoiceID = 3},
			new Item() { Name = "Item 21", InvoiceID = 3},
			new Item() { Name = "Item 3", InvoiceID = 3},
			new Item() { Name = "Item 5", InvoiceID = 4},
			new Item() { Name = "Item 4", InvoiceID = 4},
			new Item() { Name = "Item 15", InvoiceID = 4},
			new Item() { Name = "Item 35", InvoiceID = 4},
			new Item() { Name = "Item 1", InvoiceID = 5},
			new Item() { Name = "Item 4", InvoiceID = 5},
			new Item() { Name = "Item 3", InvoiceID = 6},
			new Item() { Name = "Item 2", InvoiceID = 6},
			new Item() { Name = "Item 6", InvoiceID = 6},
			new Item() { Name = "Item 11", InvoiceID = 6},
			new Item() { Name = "Item 23", InvoiceID = 6},
			new Item() { Name = "Item 1", InvoiceID = 6},
			new Item() { Name = "Item 4", InvoiceID = 6},
			new Item() { Name = "Item 20", InvoiceID = 6},
		};
	
		return list;
	}
	
	public static void DisplayData(List<Invoice> list)
	{
		foreach(var invoice in list)
		{
			Console.WriteLine(invoice.Date);
			foreach(var item in invoice.Items)
			{
				Console.WriteLine("\t" + item.Name);
			}
		}
	}

	public class EntityContext : DbContext
	{
		public EntityContext() : base(FiddleHelper.GetConnectionStringSqlServer())
		{

		}
		
		public DbSet<Customer> Customers { get; set; }
		public DbSet<Invoice> Invoices { get; set; }
	}
	
	
	public class Customer
	{
		public int CustomerID { get; set; }
		public string Name { get; set; }
		public virtual List<Invoice> Invoices { get; set; }
	}
	
	public class Invoice
	{
		public int InvoiceID { get; set; }
		public DateTime Date { get; set; }
		public int CustomerID { get; set; }
    	public virtual Customer Customer { get; set; }
		public virtual ICollection<Item> Items { get; set; }
	}
	public class Item
	{
		public int ItemID { get; set; }
		public string Name { get; set; }
		public int InvoiceID { get; set; }
		public virtual Invoice Invoice { get; set; }
	}
}