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 7: Anonymous Types (again)

The previous sample showed a basic example of using anonymous types to custom-shape the output of a LINQ query. The below sample provides a richer and more practical scenario. It transforms our list of cities into a hierarchical result collection – where we group the results around countries using an anonymous type that we define that contains the country name, a sub-collection list of city details, and the sum of the total distance of all cities within the country (computed using a lambda expression like we demonstrated in step5 above):

Listing 17

using System;
using System.Web.UI;
using System.Query;
public partial class Step7 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        TravelOrganizer travel = new TravelOrganizer();
 
        GridView1.DataSource = from location in travel.PlacesVisited
                               group location by location.Country into loc
                               select new {
                                   Country = loc.Key,
                                   Cities = loc,
                                   TotalDistance = loc.Sum(dist => dist.Distance)
                               };
           
        GridView1.DataBind();
    }
}

The GridView on our .aspx page is then defined like so:

Listing 18

<%@Page Language="C#" AutoEventWireup="true" CodeFile="Step7.aspx.cs"
Inherits="Step7" %>
<html>
<body>
    <form id="form1" runat="server">
    <div>
        <h1>Groupings with Anonymous Classes</h1>
 
        <asp:GridView ID="GridView1" 
AutoGenerateColumns="false" runat="server">
            <Columns>
            
                <asp:BoundField HeaderText="Country" DataField="Country" />
            
                <asp:TemplateField HeaderText="Cities">
                    <ItemTemplate>
                    
                        <asp:BulletedList ID="BulletedList1" runat="server"
                                          DataSource='<%#Eval("Cities")%>'
DataValueField="City"/>
                    
                    </ItemTemplate>
                </asp:TemplateField>
            
                <asp:BoundField HeaderText="Total Distance" 
DataField="TotalDistance" />
            
            </Columns>
        </asp:GridView> 
    </div>
    </form>
</body>
</html>

Notice how I’ve added a GridView templatefield column for the “Cities” column – and within that I’ve then added an <asp:bulletedlist> control (a new control built-in with ASP.NET 2.0) that databinds its values from the cities property of the hierarchical result we created using our LINQ query above. This generates output like so:

Figure 8

<img border=0 width=535 height=581src="/ArticleFiles/922/image007.jpg">

Note that all of the databind syntax and hierarchical binding support in the .aspx page above is fully supported in ASP.NET 2.0 today – so you can use this same technique with any existing app you have now. What is new (and I think very cool) is the data shaping capabilities provided by anonymous types and LINQ – which makes binding hierarchical data against ASP.NET controls very easy.

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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