/// <summary>
/// 点标记
/// </summary>
public void Show()
{
var list = new ProductList();
var customers = list.GetCustomerList();
Console.WriteLine();
Console.WriteLine("GroupBy_Nested 点标记");
//n % 5
//var result = products.GroupBy(g => g.Category).Select(g => new { Category = g.Key, products = g });
//Print(result);
}
/// <summary>
/// 点标记
/// </summary>
public void Show()
{
var list = new ProductList();
var customers = list.GetCustomerList();
Console.WriteLine();
Console.WriteLine("Skip_Nested 点标记");
//First 3 numbers:
//var result = customers.Where(c=>c.Region=="WA").J
//Print(result);
}
/// <summary>
/// 点标记
/// </summary>
public void Show()
{
var productList = new ProductList();
var customers = productList.GetCustomerList();
Console.WriteLine();
Console.WriteLine("Where_Drilldown 点标记");
//Customers from Washington and their orders:
var result = customers.Where(t => t.Region == "WA");
Print(result);
}
public void Show()
{
var list = new ProductList();
var customers = list.GetCustomerList();
var orderCounts =
from c in customers
select new { c.CustomerID, OrderCount = c.Orders.Count() };
foreach (var item in orderCounts)
{
Console.WriteLine(item);
}
}
/// <summary>
/// 查询表达式
/// </summary>
/// <param name="x"></param>
public void Show(int x)
{
var productList = new ProductList();
var customers = productList.GetCustomerList();
Console.WriteLine();
Console.WriteLine("Where_Drilldown 查询表达式");
//Customers from Washington and their orders:
var result = from t in customers
where t.Region == "WA"
select t;
Print(result);
}
/// <summary>
/// 查询表达式
/// </summary>
/// <param name="x"></param>
public void Show(int x)
{
var list = new ProductList();
var customers = list.GetCustomerList();
Console.WriteLine();
Console.WriteLine("Skip_Nested 查询表达式");
//First 3 numbers:
var result = (from a in customers
from b in a.Orders
where a.Region == "WA"
select new { a.CustomerID, b.OrderID, b.OrderDate }).Skip(3);
Print(result);
}
/// <summary>
/// 查询表达式
/// </summary>
/// <param name="x"></param>
public void Show(int x)
{
var list = new ProductList();
var customers = list.GetCustomerList();
Console.WriteLine();
Console.WriteLine("SelectMany_Compound_from_3 查询表达式");
//o.OrderDate >= new DateTime(1998, 1, 1)
var result = from a in customers
from o in a.Orders
where o.OrderDate > new DateTime(1998, 1, 1)
select new { a.CustomerID, o.OrderID, OrderDate = o.OrderDate.ToString("yyyy-MM-dd") };
Print(result);
}
/// <summary>
/// 查询表达式
/// </summary>
/// <param name="x"></param>
public void Show(int x)
{
var list = new ProductList();
var customers = list.GetCustomerList();
Console.WriteLine();
Console.WriteLine("SelectMany_Compound_from_Assignment 查询表达式");
//total >= 2000.0M
var result = from c in customers
from o in c.Orders
where o.Total >= 2000.0M
select new { c.CustomerID, o.OrderID, total = o.Total };
Print(result);
}
/// <summary>
/// 点标记
/// </summary>
public void Show()
{
var list = new ProductList();
var customers = list.GetCustomerList();
Console.WriteLine();
Console.WriteLine("SelectMany_Indexed 点标记");
//Pairs where a < b:
var result = customers.SelectMany((cust, index) =>
cust.Orders.Select(o => "Customer #" + (index + 1) +
" has an order with OrderID " + o.OrderID)
);
Print(result);
}
/// <summary>
/// 查询表达式
/// </summary>
/// <param name="x"></param>
public void Show(int x)
{
var list = new ProductList();
var customers = list.GetCustomerList();
DateTime cutoffDate = new DateTime(1997, 1, 1);
Console.WriteLine();
Console.WriteLine("SelectMany_Indexed 查询表达式");
//o.OrderDate >= cutoffDate
//var result = from c in customers
// where c.Region == "WA"
// from o in c.Orders
// where o.OrderDate >= cutoffDate
// select new { c.CustomerID, o.OrderID };
//Print(result);
}
/// <summary>
/// 点标记
/// </summary>
public void Show()
{
var list = new ProductList();
var products = list.GetProductList();
var customers = list.GetCustomerList();
var productFirstChars =
from p in products
select p.ProductName[0];
var customerFirstChars =
from c in customers
select c.CompanyName[0];
Console.WriteLine();
Console.WriteLine("Intersect_2 点标记");
//Numbers < 5:
var result = productFirstChars.Intersect(customerFirstChars).OrderBy(x => x);
Print(result);
}
/// <summary>
/// 查询表达式
/// </summary>
/// <param name="x"></param>
public void Show(int x)
{
var list = new ProductList();
var customers = list.GetCustomerList();
Console.WriteLine();
Console.WriteLine("GroupBy_Nested 查询表达式");
//n % 5
var result = (from w in customers
select new {
w.CompanyName, YearGroups = from o in w.Orders
group o by o.OrderDate.Year into yg
select new {
Year = yg.Key,
MonthGroups = from o in yg
group o by o.OrderDate.Month into mg
select new { Month = mg.Key, Orders = mg }
}
}).ToList();
Print(result);
}
