LINQ - Restriction Operators

Program.cs 19.66KB

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.ComponentModel; 
using System.IO; 
using System.Xml.Linq; 
 
namespace RestrictionOperators 
{ 
    class Program 
    { 
        static void Main(string[] args) 
        { 
            LinqSamples samples = new LinqSamples(); 
 
            //Comment or uncomment the method calls below to run or not 
 
              samples.Linq1(); // This sample  uses the where clause  to find all elements  of an array with a value  
                               // less than 5 
 
            //samples.Linq2(); // This sample uses the where clause to find all products that are out of stock 
 
            //samples.Linq3(); // This sample uses the where clause to find all products that are in  stock and cost  
                               // more than 3.00 per unit 
 
            //samples.Linq4(); // This sample uses the where  clause to find all customers in Washington and then it  
                               // uses a foreach loop to iterate over the orders collection that belongs to each  
                               // customer 
 
            //samples.Linq5(); // This sample demonstrates an indexed where clause that returns digits whose name is  
                               // shorter than their value 
        } 
 
        public class Product 
        { 
            public int ProductID { get; set; } 
            public string ProductName { get; set; } 
            public string Category { get; set; } 
            public decimal UnitPrice { get; set; } 
            public int UnitsInStock { get; set; } 
        } 
 
        public class Order 
        { 
            public int OrderID { get; set; } 
            public DateTime OrderDate { get; set; } 
            public decimal Total { get; set; } 
        } 
 
        public class Customer 
        { 
            public string CustomerID { get; set; } 
            public string CompanyName { get; set; } 
            public string Address { get; set; } 
            public string City { get; set; } 
            public string Region { get; set; } 
            public string PostalCode { get; set; } 
            public string Country { get; set; } 
            public string Phone { get; set; } 
            public string Fax { get; set; } 
            public Order[] Orders { get; set; } 
        } 
 
        public class LinqSamples 
        { 
            private List<Product> productList; 
            private List<Customer> customerList; 
 
            [Description("This sample uses the where clause to find all elements of an array with a value less than 5.")] 
            public void Linq1() 
            { 
                int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 }; 
 
                var lowNums = 
                    from num in numbers 
                    where num < 5 
                    select num; 
 
                Console.WriteLine("Numbers < 5:"); 
                foreach (var x in lowNums) 
                { 
                    Console.WriteLine(x); 
                } 
            } 
 
            [Description("This sample uses the where clause to find all products that are out of stock.")] 
            public void Linq2() 
            { 
                List<Product> products = GetProductList(); 
 
                var soldOutProducts = 
                    from prod in products 
                    where prod.UnitsInStock == 0 
                    select prod; 
 
                Console.WriteLine("Sold out products:"); 
                foreach (var product in soldOutProducts) 
                { 
                    Console.WriteLine("{0} is sold out!", product.ProductName); 
                } 
            } 
 
            [Description("This sample uses the where clause to find all products that are in stock and " + 
                     "cost more than 3.00 per unit.")] 
            public void Linq3() 
            { 
                List<Product> products = GetProductList(); 
 
                var expensiveInStockProducts = 
                    from prod in products 
                    where prod.UnitsInStock > 0 && prod.UnitPrice > 3.00M 
                    select prod; 
 
                Console.WriteLine("In-stock products that cost more than 3.00:"); 
                foreach (var product in expensiveInStockProducts) 
                { 
                    Console.WriteLine("{0} is in stock and costs more than 3.00.", product.ProductName); 
                } 
            } 
 
            [Description("This sample uses the where clause to find all customers in Washington " + 
                     "and then it uses a foreach loop to iterate over the orders collection that belongs to each customer.")] 
            public void Linq4() 
            { 
                List<Customer> customers = GetCustomerList(); 
 
                var waCustomers = 
                    from cust in customers 
                    where cust.Region == "WA" 
                    select cust; 
 
                Console.WriteLine("Customers from Washington and their orders:"); 
                foreach (var customer in waCustomers) 
                { 
                    Console.WriteLine("Customer {0}: {1}", customer.CustomerID, customer.CompanyName); 
                    foreach (var order in customer.Orders) 
                    { 
                        Console.WriteLine("  Order {0}: {1}", order.OrderID, order.OrderDate); 
                    } 
                } 
            } 
 
            [Description("This sample demonstrates an indexed where clause that returns digits whose name is " + 
                    "shorter than their value.")] 
            public void Linq5() 
            { 
                string[] digits = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" }; 
 
                var shortDigits = digits.Where((digit, index) => digit.Length < index); 
 
                Console.WriteLine("Short digits:"); 
                foreach (var d in shortDigits) 
                { 
                    Console.WriteLine("The word {0} is shorter than its value.", d); 
                } 
            } 
 
            public List<Product> GetProductList() 
            { 
                if (productList == null) 
                    createLists(); 
 
                return productList; 
            } 
 
            public List<Customer> GetCustomerList() 
            { 
                if (customerList == null) 
                    createLists(); 
 
                return customerList; 
            } 
 
            private void createLists() 
            { 
                // Product data created in-memory using collection initializer: 
                productList = 
                    new List<Product> { 
                    new Product { ProductID = 1, ProductName = "Chai", Category = "Beverages", UnitPrice = 18.0000M, UnitsInStock = 39 }, 
                    new Product { ProductID = 2, ProductName = "Chang", Category = "Beverages", UnitPrice = 19.0000M, UnitsInStock = 17 }, 
                    new Product { ProductID = 3, ProductName = "Aniseed Syrup", Category = "Condiments", UnitPrice = 10.0000M, UnitsInStock = 13 }, 
                    new Product { ProductID = 4, ProductName = "Chef Anton's Cajun Seasoning", Category = "Condiments", UnitPrice = 22.0000M, UnitsInStock = 53 }, 
                    new Product { ProductID = 5, ProductName = "Chef Anton's Gumbo Mix", Category = "Condiments", UnitPrice = 21.3500M, UnitsInStock = 0 }, 
                    new Product { ProductID = 6, ProductName = "Grandma's Boysenberry Spread", Category = "Condiments", UnitPrice = 25.0000M, UnitsInStock = 120 }, 
                    new Product { ProductID = 7, ProductName = "Uncle Bob's Organic Dried Pears", Category = "Produce", UnitPrice = 30.0000M, UnitsInStock = 15 }, 
                    new Product { ProductID = 8, ProductName = "Northwoods Cranberry Sauce", Category = "Condiments", UnitPrice = 40.0000M, UnitsInStock = 6 }, 
                    new Product { ProductID = 9, ProductName = "Mishi Kobe Niku", Category = "Meat/Poultry", UnitPrice = 97.0000M, UnitsInStock = 29 }, 
                    new Product { ProductID = 10, ProductName = "Ikura", Category = "Seafood", UnitPrice = 31.0000M, UnitsInStock = 31 }, 
                    new Product { ProductID = 11, ProductName = "Queso Cabrales", Category = "Dairy Products", UnitPrice = 21.0000M, UnitsInStock = 22 }, 
                    new Product { ProductID = 12, ProductName = "Queso Manchego La Pastora", Category = "Dairy Products", UnitPrice = 38.0000M, UnitsInStock = 86 }, 
                    new Product { ProductID = 13, ProductName = "Konbu", Category = "Seafood", UnitPrice = 6.0000M, UnitsInStock = 24 }, 
                    new Product { ProductID = 14, ProductName = "Tofu", Category = "Produce", UnitPrice = 23.2500M, UnitsInStock = 35 }, 
                    new Product { ProductID = 15, ProductName = "Genen Shouyu", Category = "Condiments", UnitPrice = 15.5000M, UnitsInStock = 39 }, 
                    new Product { ProductID = 16, ProductName = "Pavlova", Category = "Confections", UnitPrice = 17.4500M, UnitsInStock = 29 }, 
                    new Product { ProductID = 17, ProductName = "Alice Mutton", Category = "Meat/Poultry", UnitPrice = 39.0000M, UnitsInStock = 0 }, 
                    new Product { ProductID = 18, ProductName = "Carnarvon Tigers", Category = "Seafood", UnitPrice = 62.5000M, UnitsInStock = 42 }, 
                    new Product { ProductID = 19, ProductName = "Teatime Chocolate Biscuits", Category = "Confections", UnitPrice = 9.2000M, UnitsInStock = 25 }, 
                    new Product { ProductID = 20, ProductName = "Sir Rodney's Marmalade", Category = "Confections", UnitPrice = 81.0000M, UnitsInStock = 40 }, 
                    new Product { ProductID = 21, ProductName = "Sir Rodney's Scones", Category = "Confections", UnitPrice = 10.0000M, UnitsInStock = 3 }, 
                    new Product { ProductID = 22, ProductName = "Gustaf's Knäckebröd", Category = "Grains/Cereals", UnitPrice = 21.0000M, UnitsInStock = 104 }, 
                    new Product { ProductID = 23, ProductName = "Tunnbröd", Category = "Grains/Cereals", UnitPrice = 9.0000M, UnitsInStock = 61 }, 
                    new Product { ProductID = 24, ProductName = "Guaraná Fantástica", Category = "Beverages", UnitPrice = 4.5000M, UnitsInStock = 20 }, 
                    new Product { ProductID = 25, ProductName = "NuNuCa Nuß-Nougat-Creme", Category = "Confections", UnitPrice = 14.0000M, UnitsInStock = 76 }, 
                    new Product { ProductID = 26, ProductName = "Gumbär Gummibärchen", Category = "Confections", UnitPrice = 31.2300M, UnitsInStock = 15 }, 
                    new Product { ProductID = 27, ProductName = "Schoggi Schokolade", Category = "Confections", UnitPrice = 43.9000M, UnitsInStock = 49 }, 
                    new Product { ProductID = 28, ProductName = "Rössle Sauerkraut", Category = "Produce", UnitPrice = 45.6000M, UnitsInStock = 26 }, 
                    new Product { ProductID = 29, ProductName = "Thüringer Rostbratwurst", Category = "Meat/Poultry", UnitPrice = 123.7900M, UnitsInStock = 0 }, 
                    new Product { ProductID = 30, ProductName = "Nord-Ost Matjeshering", Category = "Seafood", UnitPrice = 25.8900M, UnitsInStock = 10 }, 
                    new Product { ProductID = 31, ProductName = "Gorgonzola Telino", Category = "Dairy Products", UnitPrice = 12.5000M, UnitsInStock = 0 }, 
                    new Product { ProductID = 32, ProductName = "Mascarpone Fabioli", Category = "Dairy Products", UnitPrice = 32.0000M, UnitsInStock = 9 }, 
                    new Product { ProductID = 33, ProductName = "Geitost", Category = "Dairy Products", UnitPrice = 2.5000M, UnitsInStock = 112 }, 
                    new Product { ProductID = 34, ProductName = "Sasquatch Ale", Category = "Beverages", UnitPrice = 14.0000M, UnitsInStock = 111 }, 
                    new Product { ProductID = 35, ProductName = "Steeleye Stout", Category = "Beverages", UnitPrice = 18.0000M, UnitsInStock = 20 }, 
                    new Product { ProductID = 36, ProductName = "Inlagd Sill", Category = "Seafood", UnitPrice = 19.0000M, UnitsInStock = 112 }, 
                    new Product { ProductID = 37, ProductName = "Gravad lax", Category = "Seafood", UnitPrice = 26.0000M, UnitsInStock = 11 }, 
                    new Product { ProductID = 38, ProductName = "Côte de Blaye", Category = "Beverages", UnitPrice = 263.5000M, UnitsInStock = 17 }, 
                    new Product { ProductID = 39, ProductName = "Chartreuse verte", Category = "Beverages", UnitPrice = 18.0000M, UnitsInStock = 69 }, 
                    new Product { ProductID = 40, ProductName = "Boston Crab Meat", Category = "Seafood", UnitPrice = 18.4000M, UnitsInStock = 123 }, 
                    new Product { ProductID = 41, ProductName = "Jack's New England Clam Chowder", Category = "Seafood", UnitPrice = 9.6500M, UnitsInStock = 85 }, 
                    new Product { ProductID = 42, ProductName = "Singaporean Hokkien Fried Mee", Category = "Grains/Cereals", UnitPrice = 14.0000M, UnitsInStock = 26 }, 
                    new Product { ProductID = 43, ProductName = "Ipoh Coffee", Category = "Beverages", UnitPrice = 46.0000M, UnitsInStock = 17 }, 
                    new Product { ProductID = 44, ProductName = "Gula Malacca", Category = "Condiments", UnitPrice = 19.4500M, UnitsInStock = 27 }, 
                    new Product { ProductID = 45, ProductName = "Rogede sild", Category = "Seafood", UnitPrice = 9.5000M, UnitsInStock = 5 }, 
                    new Product { ProductID = 46, ProductName = "Spegesild", Category = "Seafood", UnitPrice = 12.0000M, UnitsInStock = 95 }, 
                    new Product { ProductID = 47, ProductName = "Zaanse koeken", Category = "Confections", UnitPrice = 9.5000M, UnitsInStock = 36 }, 
                    new Product { ProductID = 48, ProductName = "Chocolade", Category = "Confections", UnitPrice = 12.7500M, UnitsInStock = 15 }, 
                    new Product { ProductID = 49, ProductName = "Maxilaku", Category = "Confections", UnitPrice = 20.0000M, UnitsInStock = 10 }, 
                    new Product { ProductID = 50, ProductName = "Valkoinen suklaa", Category = "Confections", UnitPrice = 16.2500M, UnitsInStock = 65 }, 
                    new Product { ProductID = 51, ProductName = "Manjimup Dried Apples", Category = "Produce", UnitPrice = 53.0000M, UnitsInStock = 20 }, 
                    new Product { ProductID = 52, ProductName = "Filo Mix", Category = "Grains/Cereals", UnitPrice = 7.0000M, UnitsInStock = 38 }, 
                    new Product { ProductID = 53, ProductName = "Perth Pasties", Category = "Meat/Poultry", UnitPrice = 32.8000M, UnitsInStock = 0 }, 
                    new Product { ProductID = 54, ProductName = "Tourtière", Category = "Meat/Poultry", UnitPrice = 7.4500M, UnitsInStock = 21 }, 
                    new Product { ProductID = 55, ProductName = "Pâté chinois", Category = "Meat/Poultry", UnitPrice = 24.0000M, UnitsInStock = 115 }, 
                    new Product { ProductID = 56, ProductName = "Gnocchi di nonna Alice", Category = "Grains/Cereals", UnitPrice = 38.0000M, UnitsInStock = 21 }, 
                    new Product { ProductID = 57, ProductName = "Ravioli Angelo", Category = "Grains/Cereals", UnitPrice = 19.5000M, UnitsInStock = 36 }, 
                    new Product { ProductID = 58, ProductName = "Escargots de Bourgogne", Category = "Seafood", UnitPrice = 13.2500M, UnitsInStock = 62 }, 
                    new Product { ProductID = 59, ProductName = "Raclette Courdavault", Category = "Dairy Products", UnitPrice = 55.0000M, UnitsInStock = 79 }, 
                    new Product { ProductID = 60, ProductName = "Camembert Pierrot", Category = "Dairy Products", UnitPrice = 34.0000M, UnitsInStock = 19 }, 
                    new Product { ProductID = 61, ProductName = "Sirop d'érable", Category = "Condiments", UnitPrice = 28.5000M, UnitsInStock = 113 }, 
                    new Product { ProductID = 62, ProductName = "Tarte au sucre", Category = "Confections", UnitPrice = 49.3000M, UnitsInStock = 17 }, 
                    new Product { ProductID = 63, ProductName = "Vegie-spread", Category = "Condiments", UnitPrice = 43.9000M, UnitsInStock = 24 }, 
                    new Product { ProductID = 64, ProductName = "Wimmers gute Semmelknödel", Category = "Grains/Cereals", UnitPrice = 33.2500M, UnitsInStock = 22 }, 
                    new Product { ProductID = 65, ProductName = "Louisiana Fiery Hot Pepper Sauce", Category = "Condiments", UnitPrice = 21.0500M, UnitsInStock = 76 }, 
                    new Product { ProductID = 66, ProductName = "Louisiana Hot Spiced Okra", Category = "Condiments", UnitPrice = 17.0000M, UnitsInStock = 4 }, 
                    new Product { ProductID = 67, ProductName = "Laughing Lumberjack Lager", Category = "Beverages", UnitPrice = 14.0000M, UnitsInStock = 52 }, 
                    new Product { ProductID = 68, ProductName = "Scottish Longbreads", Category = "Confections", UnitPrice = 12.5000M, UnitsInStock = 6 }, 
                    new Product { ProductID = 69, ProductName = "Gudbrandsdalsost", Category = "Dairy Products", UnitPrice = 36.0000M, UnitsInStock = 26 }, 
                    new Product { ProductID = 70, ProductName = "Outback Lager", Category = "Beverages", UnitPrice = 15.0000M, UnitsInStock = 15 }, 
                    new Product { ProductID = 71, ProductName = "Flotemysost", Category = "Dairy Products", UnitPrice = 21.5000M, UnitsInStock = 26 }, 
                    new Product { ProductID = 72, ProductName = "Mozzarella di Giovanni", Category = "Dairy Products", UnitPrice = 34.8000M, UnitsInStock = 14 }, 
                    new Product { ProductID = 73, ProductName = "Röd Kaviar", Category = "Seafood", UnitPrice = 15.0000M, UnitsInStock = 101 }, 
                    new Product { ProductID = 74, ProductName = "Longlife Tofu", Category = "Produce", UnitPrice = 10.0000M, UnitsInStock = 4 }, 
                    new Product { ProductID = 75, ProductName = "Rhönbräu Klosterbier", Category = "Beverages", UnitPrice = 7.7500M, UnitsInStock = 125 }, 
                    new Product { ProductID = 76, ProductName = "Lakkalikööri", Category = "Beverages", UnitPrice = 18.0000M, UnitsInStock = 57 }, 
                    new Product { ProductID = 77, ProductName = "Original Frankfurter grüne Soße", Category = "Condiments", UnitPrice = 13.0000M, UnitsInStock = 32 } 
                }; 
 
                // Customer/Order data read into memory from XML file using XLinq: 
                customerList = ( 
                    from e in XDocument.Load("Customers.xml"). 
                              Root.Elements("customer") 
                    select new Customer 
                    { 
                        CustomerID = (string)e.Element("id"), 
                        CompanyName = (string)e.Element("name"), 
                        Address = (string)e.Element("address"), 
                        City = (string)e.Element("city"), 
                        Region = (string)e.Element("region"), 
                        PostalCode = (string)e.Element("postalcode"), 
                        Country = (string)e.Element("country"), 
                        Phone = (string)e.Element("phone"), 
                        Fax = (string)e.Element("fax"), 
                        Orders = ( 
                            from o in e.Elements("orders").Elements("order") 
                            select new Order 
                            { 
                                OrderID = (int)o.Element("id"), 
                                OrderDate = (DateTime)o.Element("orderdate"), 
                                Total = (decimal)o.Element("total") 
                            }) 
                            .ToArray() 
                    }) 
                    .ToList(); 
            } 
        } 
    } 
} 

http://code.msdn.microsoft.com/LINQ-Restriction-Operators-b15d29ca/sourcecode?fileId=23938&pathId=200844508

 

101 LINQ Samples

Learn how to use LINQ in your applications with these code samples, covering the entire range of LINQ functionality and demonstrating LINQ with SQL, DataSets, and XML.

http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b/viewsamplepack