Why my update method dose not work?

I will show you some pictures about my question.Also I wish you can point out the error in the demo project.

1. create a new website called WebSite1


2. connect to the demo database


3.create a test dataset nameed TestDataSet.xsd


4.create a TableAdapter

















5. drag and drop a Gridview to the default page


6.create a new gridview datasource










7.the select and delete methods work fine


8.but the update method dose not work