C# 4 and .NET 4

standard Query operators ❘ 275
where n.StartsWith("J")
orderby n
select n).ToList();
Console.WriteLine("First iteration");
foreach (string name in namesWithJ)
{
Console.WriteLine(name);
}
Console.WriteLine();
names.Add("John");
names.Add("Jim");
names.Add("Jack");
names.Add("Denny");
Console.WriteLine("Second iteration");
foreach (string name in namesWithJ)
{
Console.WriteLine(name);
}
In the result, you can see that in between the iterations the output stays the same although the collection
values have changed:
First iteration
Juan
Second iteration
Juan
sTandard query oPeraTors
Where, OrderByDescending, and Select are only a few of the query operators defined by LINQ. The
LINQ query defines a declarative syntax for the most common operators. There are many more query
operators available with the Enumerable class.
The following table lists the standard query operators defined by the Enumerable class:
sTandard query oPeraTors
Where OfType
Select SelectMany
OrderBy ThenBy OrderByDescending
ThenByDescending Reverse
desCriPTion
Filtering operators define a restriction to the elements returned.
With the Where query operator you can use a predicate, for
example, defined by a Lambda expression that returns a bool.
OfType filters the elements based on the type and
returns only the elements of the type TResult.
Projection operators are used to transform an object into a new
object of a different type. Select and SelectMany define a
projection to select values of the result based on a selector
function.
Sorting operators change the order of elements
returned. OrderBy sorts values in ascending order;
OrderByDescending sorts values in descending order.
ThenBy and ThenByDescending operators are used for a
secondary sort if the first sort gives similar results. Reverse
reverses the elements in the collection.
continues
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