Simple LINQ :

  • MSDN : "A query is a set of instructions that describes what data to retrieve from a given data source (or sources) andwhat shape and organization the returned data should have. A query is distinct from the results that it produces."
  • LINQ Querying a string and serializing an array
  • Query Expression : MSDN " A query expression is a query expressed in query syntax. A query expression is a first-class language construct. It is just like any other expression and can be used in any context in which a C# expression is valid. A query expression consists of a set of clauses written in a declarative syntax similar to SQL or XQuery. Each clause in turn contains one or more C# expressions, and these expressions may themselves be either a query expression or contain a query expression."
    • A query expression must begin with a from clause and must end with a select or group clause.
    • Between the first from clause and the last select or group clause, it can contain one or more of these optional clauses: where, orderby , join , let and even additional from clauses.
    • You can also use the into keyword to enable the result of a join or group clause to serve as the source for additional query clauses in the same query expression.

Major Standard Query Operators

Family

 Operators
Filetering ofType, Where
Projection Select, Selectmany
Partioning Skip, SkipWhile, Take, TakeWhile
Concatenation Concat
Ordering  OrderBy , Then , Reverse
Grouping GroupBy
Set Distinct, Except, Intersect, Union
Conversion AsNumerable, AsQQuerablem Cast, ToArray, ToDictionary, ToList
Equality  SequenceEqual
Element  ElementAt, ElementAtorDefault, First, FirstorDefault, Lastm LastOrDefault, Single, SingleOrDefault
Generation DefaultIfEmpty, Empty, Range, Repeat
Quantifiers  All, Any, Contains
Aggregation  Aggregate, Average, Count, Max,Min, Sum

 

Add New web site

Add a Label Control in Default.aspx

Codes : Default.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>mm.LINQSimple1: from : where : select clauses</title>
<link href="main.css" rel="stylesheet" type="text/css" />
</head>
<body >
<form id="form1" runat="server">
<div id="div1"> This is an example of Serializing an Array String <br />
<asp:Label ID="L1" runat="server" ></asp:Label>
</div>
</form>
</body>
</html>
 

Code Default.aspx.cs

using System;
using System.Linq;

public partial class _Default : System.Web.UI.Page
{

protected void Page_Load(object sender, EventArgs e)
{
string[] words = { "March", "April", "May", "June", "January", "February", "October", "December" };
// LINQ Query for short words and long words
var shortWords = from word in words where word.Length <= 5  select word;
var LongWords = from word in words where word.Length >= 5 select word;

// Print each word out with foreach loop/ LINQ query
L1.Text += "&nbsp Short Words : <br/>";
foreach (var word in shortWords)
{
L1.Text += "&nbsp : " + word.ToString();
}
L1.Text += " <hr> Long Words <br/>" ;
foreach (var word in LongWords)
{
//Console.WriteLine(word);
L1.Text += "&nbsp : " + word.ToString();
}
}
}



Runt time : in the first query the words those are less than 5 will be filtered, and in the next loop those words are equal or more than 5 character in length will be filtered,