Mastering the .NET Code Model

Copyright © 2006-2008. Iron Speed Inc. All rights reserved

Mastering the .NET Code Model

Visit us: www.ironspeed.com Download the Free Edition: www.ironspeed.com/download

2

Copyright © 2006-2008. Iron Speed® Inc. All rights reserved

ASP.NET Code Model

Single-File Page Model

Layout and Code in one ASPX file

Used only for the simplest applications

3


ASP.NET Code Model

Code-Behind Page Model

Most common in practice

Separate Layout and Code

Layout in ASPX

Code-behind in .VB or .CS

No performance difference

Allows re-use of common code

Designers can design layout, while developers can write code

Best practice for an N-tier application

4


Code-Behind

Code-Behind is specified in the ASPX

5


Code-Behind

Code-Behind is derived from the Page class (or another subclass of Page class)

6


Best Practices - .NET Code Model

Use Code-Behind Page Model for extensibility


Page Lifecycle

8


Page Lifecycle

Sequence of steps a page goes through

Initialize

Load the user interface controls

Read data from the database

Display the page

And later…

Validate data

Save data into database

Redirect back to calling page

etc.

9


Page Lifecycle

.NET handles

Loading of the page

Converting ASP controls to HTML controls

Rendering controls on the page

But at key points during the page lifecycle, .NET raises events for you to do your work

Your job: Handle various events to load data from database, initialize content in controls

10


.NET’s Event-based Model

Program by responding to events

Write an event handler

Initial page display has three events

User actions on page (e.g., button click) has one additional event

11


12


After Displaying a Page

Server releases the page instance

Nothing about the page or the data on the page is kept on the server

Any state information must be maintained by you in “ViewState”

13


What is a Postback?

User’s action causes a Postback

An event is raised

Page instance is re-created

UI Control data is repopulated from ViewState

Server-side event handler is called

Examples

Button click

Selected item in dropdown

Typed text in a textbox

Must register Event Handler to request a postback

14


User Actions cause “Postback”

Four events raised during Postback

Registered Event Handler called between Load and PreRender

15


16


During Postback

Check IsPostback to determine whether in Postback state

Performance Tip: Only load data during initial display (Not IsPostback)

17


State Management

ViewState is a standard feature of .NET

By default, state information maintained in HTML sent to browser

Encoded, but not encrypted

18


State Management

ViewState can be optionally saved in Session, Cache, File or Database - but:

Additional work required

Session or Cache can get timed out

File or Database requires regular cleanup

Bloats the page content, but best to leave it as Page

19


Best Practices – Page Lifecycle

Do most of the work by handling Load event

Init should be used only for initializing event handlers

PreRender should only be used to handle dependent controls

Security for a page should be checked in Load

Use IsPostback extensively to improve performance and minimize loading data from database

Use “Page” ViewState – even though it sends lots of data to the browser


Ajax

21


Using Ajax

ASP.NET Ajax creates fast and flicker-free updates

Extremely simple to implement –

Just surround ASP Controls with UpdatePanel

Only sends back content that has changed

Browser only paints changed content

Can have multiple and/or nested UpdatePanels

Code-behind does not change when using Ajax

22


Using Ajax

Can show progress using UpdateProgress

Use animated GIF image

23


Best Practices – Ajax

Best to use a single UpdatePanel

Using multiple UpdatePanels may require special handling when updating dependent information


Master Pages

25


Master Pages

Creates a consistent layout

Centralizes common functionality

Easier to maintain

Typical use:

Master Page contains:

Styles

Header, Menu and Footer

Individual page contains:

Content

26


Master Pages

27


Master Pages

.NET merges Master pages with Page Content

Master pages can inherit from other master pages

28


Best Practices – Master Pages

Create multiple Master Pages for different needs

Nest Master Pages if needed

Include all CSS Styles, Javascript, etc. in Master Pages

Keep Page Content focused on actual data


N-Tier Applications

30


N-Tier Application

Divide application into N-Tiers

Layout in ASPX pages

UI Code in Code-Behind code files

Business Layer

Data Access Layer

Stored Procedures

31


N-Tier Application

32


Best Practices – N-Tier Application

Changes to layout should not impact Code-Behind

Changes to Database Schema should have minimal impact on UI Layer

Data Access Layer must use Strongly Typed objects

Paging must be done in the database, not in memory

ASP GridView, ListView etc. do paging in memory

Concurrency handling is important in highly asynchronous applications


Iron Speed Designer

34


Iron Speed Designer

Implements Best Practices for

.NET Code Model

Page Lifecycle

Ajax

Master Pages

N-Tier Applications

Lets you focus on what is most important

Your business logic

Use the .NET Code Model knowledge to extend

35


Three Recent Game Changing Enhancements

Layout Customizations

Use Spreadsheet Grid

Toolbox – Drag and drop

Easily add pre-configured panels and controls

Code Customizations

Use Excel-like Formulas

36


Page Layout Customization

Spreadsheet shows a ‘logical representation’ of page section

Drag and drop to arrange controls

Designer converts page layout to HTML (ASPX)

(You don’t have to know any HTML or ASPX!)

Cell Editor allows fine-grained tuning and formatting

- Add any HTML or ASPX

- Change font, bold, italics, alignment, cell borders, cell width

37


Using Toolbox Controls

Drag and drop controls onto your Web page

Toolbox controls are databound – there’s nothing to hook up!

- Fields, labels and entire panels!

38


Formula Language

Game Changing Enhancement to Version7.0

Excel-like

Most common tasks can be done – 75 to 80%

No need to know VB.NET or C#

Easy to extend – local and global extensions

39


Key Questions

What is your time worth?

What is the ROI?

40


Questions?

Mastering the .NET Code Model

Technology

Transcript of Mastering the .NET Code Model