Building and Using a LINQ for SQL Class Library with ASP.NET 2.0
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by Scott Guthrie
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Step 5: Build a simple Products Listing Page

To give a simple taste of using LINQ, we will build a simple Product Listing page that lists products like the image below.

Figure 9

To implement this, I will add a templated ASP.NET DataList control to the .aspx page using the markup below to define the UI for each product in our list.

Listing 1

<span lang=EN><asp:DataList ID="DataList1" RepeatColumns="2" runat="server">
        <div class="productimage">
             <img src="images/productimage.gif" />
         <div class="productdetails">
             <div class="ProductListHead">
             <span class="ProductListItem">
                 <%# Eval("UnitPrice", "{0:c}") %>
 </asp:DataList> </span>

I can then use the below code-behind class to execute a LINQ query against the class library data model we defined in our class library previously to retrieve all of the products in the database supplier by the "Exotic Liquids" supplier and sorted by the product name.

Listing 2

<span lang=EN>using System;
 using System.Web;
 using System.Query;
 using LINQClassLibrary;
 public partial class HelloWorld : System.Web.UI.Page { </span>
<span lang=EN>
     protected void Page_Load() {</span>
<span lang=EN>
         NorthwindDataContext db = new NorthwindDataContext();
         DataList1.DataSource = from p in db.Products
                                where p.Supplier.CompanyName == "Exotic Liquids" 
                                orderby p.ProductName
                                select p;
 } </span>

Notice how the LINQ query is strongly-typed and can incorporate the Product/Supplier entity association we setup earlier (for example, note how the where statement is able to search by the product's Supplier.CompanyName property which is stored in the Suppliers table and is linked to the Products table via a primary key/foreign key relationship). 

This strong typing model means I get compile-time checking of my LINQ queries today and will get full intellisense support with the new release of Visual Studio.  No more runtime SQL syntax errors!

And that is it.  No additional code required. 

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User Comments

Title: ras   
Name: rasd
Date: 2012-05-05 4:29:50 AM
Title: How to integrate with XLINQ in eixsting applications   
Name: Senthil
Date: 2008-12-17 12:20:06 AM
How to integrate with XLINQ in eixsting applications?
Title: nice   
Name: john
Date: 2006-09-20 5:21:27 AM
nice.. that give me a point

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