Below are some excellent articles about Asp.net Ajax:
1. Extending the Imagemap HTML control with Ajax 1.0 extensions (a detail about this place is displayed when you move your mouse over an image, especially a map)
Extended: When you move your cursor over an entry (unique identifier) in a gridview or other control, the related information is displayed.
2. Introducing Windows Services
Introduction: introduces Windows Services.
3. Create client controls in ASP. NET 2.0 Ajax 1.0 extensions
Detail: In this article Bilal Haidar demonstrates how to create a basic client control grid with Edit/delete/create functionalities with ASP. NET 2.0 Ajax 1.0 extensions. (You can just pull it)
4. Crystal Report for Visual Studio. NET
Introduction: although it was a long time ago, it seems to be of great guiding significance.
Too much. Learn more slowly.