PV247 – Development I
Introduction to ASP.NET and related technologies


Overview
oASP.NET Basics
oWhat is ASP.NET?
oWhat is a request?
oHow does ASP.NET deal with stateless http?
oASP.NET request/page/control life cycle
oREST Services
oKentico CMS Platform Basics
oCMS.IO namespace
o
o
o

What is ASP.NET?
•Active Server Pages .NET
•
•Platform for creating dynamic web applications
•
•You can use any .NET language as a code-behind
•
•Development of ASP.NET WebForms applications can be similar to the development of WinForms
applicatons. Similar, not same!

Example of ASP.NET page



ASP.NET page – code behind



What is a request?



What is a request?
•Main thing you need to remember about HTTP protocol: •
HTTP is stateless protocol!
•
•But we need state in dynamic web applications!
•

How does ASP.NET deal with stateless http?
•The answer is ... ViewState!
•
•It is a technique used by an ASP.NET Web page to persist changes to the state of a Web Form across
postbacks (HTTP POST to the same page that the form is on).
•
•Use ViewState carefuly and only when it‘s really needed! It‘s helpful technique, but it might
become too greedy and can cause the application to be less effective.

ViewState – How is it send within requests?



ASP.NET page/control life cycle
•To be able to work with ASP.NET pages and controls properly you need to understand the life cycle
of these elements.
•
•Most importat phases of page/control life cycle are:
•PreInit
•Init
•Load
•PreRender
•Render
•

ASP.NET page/control life cycle
Source: http://i.msdn.microsoft.com/dynimg/IC152667.gif


Where to get more information?
•Where to start:
http://msdn.microsoft.com/en-us/library/ywdtth2f%28v=vs.71%29.aspx
•
•More about page life cycle:
http://msdn.microsoft.com/en-us/library/ms178472.aspx
•
•More details about how the ViewState works:
http://msdn.microsoft.com/en-us/library/ms972976.aspx
•
•

Let‘s have a REST!
•Representational state transfer (REST) is a style of a service architecture •Instead of complex
technologies (RPC, SOAP, etc.) you use simple HTTP requests which are supported by all the clients!
•Commonly used formates of REST responses are XML, JSON, AtomPub

Let‘s have a REST!
•Conforming to the REST constraints is referred to as being "RESTful„ service
–Access the objects within the system defining clear structure of URLs
–The structure of URLs should be self-explaining and self-navigating
•Kentico CMS supports RESTful service
•

How to request a REST Service
•Create request
•Wait for response
•That‘s all!
•
•DEMO

CMS.IO
•Layer between Kentico CMS and System.IO
•
CMS.IO
Kentico CMS
business
layer
System.IO
Azure blob API
...

CMS.IO
•Allows the system to use various IO providers (local file system, Azure Blob, Amazon S3, …)
•To implement a provider you inherit from the base class and override the IO methods
–Directory
–File
–FileStream
–etc.