static void Main(string[] args)
{
NorthwindDataContext nw = new NorthwindDataContext();
//The following queries examples are from Microsoft.
//The examples from MS did not include the foreach loop or the WriteLine. I added those.
//See Sample.cs for samples I did while in class.
//
// Query #1.
List <int> numbers = new List <int>()
{
5, 4, 1, 3, 9, 8, 6, 7, 2, 0
};
// The query variable can also be implicitly typed by using var
Console.WriteLine("Filtering Query");
IEnumerable <int> filteringQuery =
from num in numbers
where num < 3 || num > 7
select num;
foreach (var num in filteringQuery)
{
Console.WriteLine(num);
}
Console.WriteLine();
Console.WriteLine();
// Query #2.
Console.WriteLine("Ordering Query");
IEnumerable <int> orderingQuery =
from num in numbers
where num < 3 || num > 7
orderby num ascending
select num;
foreach (var num in orderingQuery)
{
Console.WriteLine(num);
}
Console.WriteLine();
Console.WriteLine();
// Query #3.
Console.WriteLine("Groupping Query");
string[] groupingQuery = { "carrots", "cabbage", "broccoli", "beans", "barley" };
IEnumerable <IGrouping <char, string> > queryFoodGroups =
from item in groupingQuery
group item by item[0];
foreach (var item in groupingQuery)
{
Console.WriteLine(item);
}
Console.WriteLine();
Console.WriteLine();
List <int> numbers1 = new List <int>()
{
5, 4, 1, 3, 9, 8, 6, 7, 2, 0
};
List <int> numbers2 = new List <int>()
{
15, 14, 11, 13, 19, 18, 16, 17, 12, 10
};
Console.WriteLine("Average");
// Query #4.
var average = numbers1.Average();
Console.WriteLine(average);
Console.WriteLine();
Console.WriteLine();
// Query #5.
Console.WriteLine("Concatenation Query");
var concatenationQuery = numbers1.Concat(numbers2);
foreach (var item in concatenationQuery)
{
Console.WriteLine(item);
}
Console.WriteLine();
Console.WriteLine();
// Query #6.
Console.WriteLine("Large Number Query");
var largeNumbersQuery = numbers2.Where(c => c > 15);
foreach (var item in largeNumbersQuery)
{
Console.WriteLine(item);
}
Console.WriteLine();
Console.WriteLine();
// Query #7.
Console.WriteLine("Numbers Query");
// Using a query expression with method syntax
int numCount1 =
(from num in numbers1
where num < 3 || num > 7
select num).Count();
// Better: Create a new variable to store
// the method call result
IEnumerable <int> numbersQuery =
from num in numbers1
where num < 3 || num > 7
select num;
int numCount2 = numbersQuery.Count();
foreach (var item in numbersQuery)
{
Console.WriteLine(item);
}
Console.WriteLine();
Console.WriteLine("Numbers Query Using var");
//The previous query can be written by using implicit typing with var, as follows:
var numCount = from num in numbers1
where num < 3 || num > 7
select num;
int numCount3 = numCount.Count();
foreach (var item in numCount)
{
Console.WriteLine(item);
}
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("Group Join Query");
//This query creates a group join, and then sorts the groups based on the category element,
//which is still in scope. Inside the anonymous type initializer, a sub-query orders all the matching
//elements from the products sequence.
var groupJoinQuery2 =
from category in nw.Categories
join prod in nw.Products on category.CategoryID equals prod.CategoryID into prodGroup
orderby category.CategoryName
select new
{
Category = category.CategoryName,
Products = from prod2 in prodGroup
orderby prod2.ProductName
select prod2
};
foreach (var productGroup in groupJoinQuery2)
{
Console.WriteLine(productGroup.Category);
foreach (var prodItem in productGroup.Products)
{
Console.WriteLine(" {0,-10} {1}", prodItem.ProductName, prodItem.CategoryID);
}
}
Console.ReadLine();
}
static void Samples(string[] args)
{
NorthwindDataContext nw = new NorthwindDataContext();
//Int array
int[] numbers = { 5, 4, 1, 3, 9, 8, 7, 2, 0 };
//String array
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 it's value", d);
}
Console.WriteLine();
Console.WriteLine();
var textNums = from n in numbers
select digits[n];
foreach (var t in textNums)
{
Console.WriteLine(t);
}
Console.WriteLine();
Console.WriteLine();
var products = from p in nw.Products
select new
{
p.ProductName,
p.CategoryID,
p.UnitPrice
};
foreach (var w in products)
{
Console.WriteLine("{0} is in the category {1} and costs {2}", w.ProductName, w.CategoryID, w.UnitPrice);
}
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("Query with the where clause.");
//Querys with the where clause.
var orders = from c in nw.Customers
from o in c.Orders
where o.OrderDate >= new DateTime(1998, 1, 1)
select new { c.CustomerID, o.OrderID, o.OrderDate };
foreach (var order in orders)
{
Console.WriteLine("Order with an id of {0}, is for the customer with an id of {1} was placed on {2}",
order.OrderID, order.CustomerID, order.OrderDate);
}
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("Query with the where clause.");
Product prod = (from p in nw.Products
where p.ProductID == 12
select p).FirstOrDefault();
Console.WriteLine(prod.ProductName);
Console.WriteLine();
Console.WriteLine();
string[] words = { "belief", "relief", "reciept", "field" };
var iAfterE = words.Any(w => w.Contains("ie"));
Console.WriteLine("The list coantains a word or words that contain 'ie' is {0}", iAfterE);
Console.WriteLine();
Console.WriteLine();
////This is broken:
//var q = from c in nw.Categories
// join p in nw.Products on c.CategoryID equals p.CategoryID into ps
// from x in ps.DefaultIfEmpty()
// select new
// {
// CategID = c.CategoryID, ProductName = p.CategoryID == null
// }
var cats = from c in nw.Categories
select c;
foreach (var cat in cats)
{
Console.WriteLine("The category description is {0}", cat.Description);
}
Console.ReadLine();
}
