ASP.NET 3.5 For Dummies®

8.5. Updating Data with a LINQ Query

LINQ to SQL does more than just select data for viewing: It selects it for updates as well. You use the query to get a subset of the data (maybe a subset with just one item) and then loop through the item(s) to do updates. In this section, you add multiple exclamation marks (!) to some items and view the results.

The follow sections insert strange content (exclamation marks) into your Northwind database. Make sure that you have a clean copy of the database set aside for future use.

8.5.1. Exclaiming with an Extension method

When you type in Code view (see Figure 8-6), you've no doubt seen IntelliSense pop up all those interesting functions like ToLower(), ToUpper(), and ToExclaim(). Okay, maybe you haven't seen ToExclaim() yet in IntelliSense, but you're about to!

Figure 8-6. IntelliSense for the extension method ToExclaim().

Extension methods let you tack on functions of your own. The only catch is that the extension code must be wrapped in a Visual Basic Module, not in the .aspx page itself. Follow these steps to create the ToExclaim() extension method:

1. In your project's App_Code folder, add a new text file named extmodule.vb (FileAdd New ...