Using LINQ with ASP.NET (Part 1): ASP Alliance

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Using LINQ with ASP.NET (Part 1)

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by Scott Guthrie
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Step 6: Anonymous Types

One of the new C# and VB language features that LINQ can take advantage of is support for “Anonymous Types”. This allows you to easily create and use type structures inline without having to formally declare their object model (instead it can be inferred by the initialization of the data). This is very useful to “custom shape” data with LINQ queries.

For example, consider a scenario where you are working against a database or strongly-typed collection that has many properties – but you only really care about a few of them. Rather than create and work against the full type, it might be useful to only return those properties that you need. To see this in action we’ll create a step6.aspx file like so:

Listing 15

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Step6.aspx.cs"
Inherits="Step6" %>
<html>
<body>
    <form id="form1" runat="server">
    <div>
        
        <h1>Anonymous Type</h1>
    
        <asp:GridView ID="GridView1" runat="server">
        </asp:GridView>
        
    </div>
    </form>
</body>
</html>

And within our code-behind file we’ll write a LINQ query that uses anonymous types like so:

Listing 16

using System;
using System.Web.UI;
using System.Query;
public partial class Step6 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        TravelOrganizer travel = new TravelOrganizer();
 
        GridView1.DataSource = from location in travel.PlacesVisited
                               orderby location.City
                               select new {
                                    City = location.City,
                                    Distance = location.Distance
                               };
           
        GridView1.DataBind();
    }
}

Note that instead of returning a “location” from our select clause like before, I am instead creating a new anonymous type that has two properties – “City” and “Distance”. The types of these properties are automatically calculated based on the value of their initial assignment (in this case a string and an int), and when databound to the GridView produce an output like so:

Figure 7

<img border=0 width=276 height=496src="/ArticleFiles/922/image006.jpg">

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User Comments

Title: linq
Name: rohit
Date: 2012-10-11 5:04:12 AM
Comment:
thanks a lot,but need more explanation

Title: uk
Name: hjkhjk
Date: 2012-07-30 2:22:48 AM
Comment:
hjkhjkhjkhjk

Title: Linq
Name: hanston
Date: 2012-06-04 2:02:15 PM
Comment:
thanks a lot....but the images aren't shown.......

Title: Language Integrated Query
Name: Daniel Kamroon
Date: 2012-03-14 7:22:12 AM
Comment:
Thank you very much. This has become my best material on LINQ topic. You made it very simple and understandable, thanks for sharing with us. Some other good articles on LINQ I was found over internet during searching this topic which also explained very well about LINQ, URL links of those posts are....
http://msdn.microsoft.com/en-us/library/bb907622.aspx
http://mindstick.com/Articles/9ca8fabd-49ef-4e4d-855b-74fc523d9138/?LINQ%20%28Language%20Integrated%20Query%29
http://www.codeproject.com/Articles/188935/LINQ-Demo-with-ASP-NET-Web-Application

Lastly, I would like to say thanks to everyone for your precious post.

Title: Sql Linq -simple query
Name: Manish Vala
Date: 2011-02-12 4:23:52 AM
Comment:
protected void Page_Load(object sender, EventArgs e)
{
//DateTime d = DateTime.Now;

string[] Name = {" Manish"," Sunil", "Rohan", "Ashok", "Mahendra" };

GridView1.DataSource = from name in Name where name.Length > 5 orderby name select name.ToUpper();
GridView1.DataBind();}

Title: SQL LINQ-A query
Name: Subhashini Janakiraman
Date: 2010-12-16 2:48:23 AM
Comment:
In the statement below which you have used,I want to know what Northwind refers to.Is it a dataset or a class?.Please reply me so.
Northwind db=new Northwind();

Title: thanks alot
Name: avrail
Date: 2010-09-26 1:38:46 AM
Comment:
thanks a lot for this article

Title: Using LINQ with ASP.NET
Name: S.Kumar
Date: 2010-04-08 3:52:48 PM
Comment:
Really a nice article, gave me a nice overview about LINQ

Title: er
Name: sdf
Date: 2009-11-14 5:46:55 AM
Comment:
protected void Page_Load(object sender, EventArgs e)
{
string[] cities = { "London", "Amsterdam", "San Francisco", "Las Vegas",
"Boston", "Raleigh", "Chicago", "Charlestown",
"Helsinki", "Nice", "Dublin" };

GridView1.DataSource = from city in cities
where city.Length > 4
orderby city
select city.ToUpper();

GridView1.DataBind();
}

Title: nice
Name: vice
Date: 2009-11-14 5:45:23 AM
Comment:
GridView1.DataSource = from city in cities
where city.Length > 4
orderby city
select city.ToUpper();

Title: jeyakumar
Name: jayakumar
Date: 2009-11-14 5:40:46 AM
Comment:
it looking like me

Title: ok
Name: kumar
Date: 2009-11-14 5:37:29 AM
Comment:
nice but not understand

Title: Topics
Name: Dhanya
Date: 2009-10-19 6:09:06 AM
Comment:
I am not understand this topics..

Title: Trying To Get a Handle On This LINQ Stuff
Name: Vibha Kant Pandey
Date: 2009-04-21 3:05:18 AM
Comment:
This article really enabled me to understand the concept of linq. the only problem i faced with this article is that i was not redirected to the correct place to download Linq May ctp

Title: About LINQs in ASP.NET
Name: SitaRamReddy.Vempada
Date: 2009-04-01 5:47:16 AM
Comment:
This article help me a lot in LINQ concept, I thank to all who are in this unit

Thanks & Regards,
srvempada

Title: Using LINQ with ASP.NET (Part 1)
Name: joseph jelasker
Date: 2009-03-28 1:52:20 AM
Comment:
This article really enabled me to understand the concept of linq. the only problem i faced with this article is that i was not redirected to the correct place to download Linq May ctp

Thanks a lot

Title: LINQ in 2005 and 2008
Name: Manigandan
Date: 2008-12-16 6:38:07 AM
Comment:
1.We are having this LINQ concept in VS2005 itself...
What is extra facility added in VS2008.

2.If i want to install LINQ separately in VS2005, What is the software that i have to install?

Title: Good one
Name: Shailendra
Date: 2008-12-09 2:24:22 AM
Comment:
Thanks for all, its very easy to know about linq from these articles.

thanks once again

Title: Trying To Get a Handle On This LINQ Stuff
Name: D Wiley
Date: 2008-11-21 9:21:36 AM
Comment:
This is on of the best walkthroughs I have seen on the subject.

Title: Leraning LINQ
Name: Manjeev kumar singh
Date: 2008-10-03 4:00:41 AM
Comment:
This one is most useful article LINQ on web. its really good start for how is beginner in LINQ....
Really thanks

Title: Using Richer Collections
Name: Nithya K
Date: 2008-09-18 6:58:04 AM
Comment:
Now i got .Its my mistake.
It is very useful

Title: Using Richer Collections
Name: Nithya K
Date: 2008-09-18 6:00:18 AM
Comment:
i got an error while executing

Title: Using Richer Collections
Name: Nithya K
Date: 2008-09-18 5:53:19 AM
Comment:
\
\S
\
\

Title: Leraning LINQ
Name: vanitha
Date: 2008-09-16 1:31:46 AM
Comment:
Very useful in learning the basic concepts of LINQ.

Title: Using LINQ with ASP.NET
Name: Durai karthik M
Date: 2008-03-15 7:20:50 AM
Comment:
Very clear to understand the LINQ concept . Keep up the good work

Title: -
Name: martin
Date: 2008-01-21 4:41:46 AM
Comment:
The images aren't shown... you need to remake the picture HTML