LINQ query

1. Linq Inquire about

grammar ：

var QueryResults= from x in Enumerating collections

where Conditions

OrderBy  Field Ascending/Descending

Select x;

Extension method ：

var QueryResults=  Enumerating collections .Where( Conditions )

.OderByDescending( Conditions )

.Select( Field );

Filter data that meets the criteria , Commonly used Linq Syntax or extension method .

2. Postpone query

var names = new List { “Nino”, “Alberto”, “Juan”, “Mike”, “Phil” };

var namesWithJ = from n in names

where n.StartsWith(“J”)

orderby n

select n;

WriteLine(“First iteration”);

foreach (string name in namesWithJ)

{

WriteLine(name);

}

WriteLine();

names.Add(“John”);

names.Add(“Jim”);

names.Add(“Jack”);

names.Add(“Denny”);

WriteLine(“Second iteration”);

foreach (string name in namesWithJ)

{

WriteLine(name);

}

WriteLine();

The output remains the same between iterations , But the values in the set changed .