Visual Web Developer

1

• Visual Web Developer
• Workshop

2
Aim of Today

• To enable you to assess whether or not
  Microsofts Visual Web Developer Express Edition
  2005 is something that would benefit you in your
  teaching.

3
Relevance to A Level Curriculum

• Two units Web Development (Unit 5 ) and Web
  Management (Unit 13)
• Unit 13 says that The website you build in Unit
  5 had only limited functionality
• Units 13 suggests creating a data entry form on
  the site linked to a database
• (Edexcel AS/A GCE in Applied ICT Issue 1
  February 2005)

4
Objectives for the Afternoon

• Explain the meaning of the terms stateless,
  client-side processing and server-side
  processing.
• Explain the difference between .NET, Visual
  Studio and Visual Web Developer Express Edition.
• Locate a free copy of Visual Web Developer
  Express Edition 2005 (and supporting materials).
• Develop a website to read and write records from
  a database using Visual Web Developer Express
  Editions high-level data access and data display
  controls.

5
Web Applications
Database
Web Server
Client
6
.NET / Visual Studio / VWD

• .NET aims to support universal data access by
  allowing centrally-held data to be seen and
  edited by a PC, a PDA, a cell phone or any other
  Internet-enabled device.
• The .NET framework is at the heart of the .NET
  strategy. It manages and executes applications
  and web services.
• Currently the framework only exists for Windows.
• Visual Studio is Microsofts industrial-strength
  development environment based on the .NET
  framework.
• Visual Web Developer is a light version of
  Visual Studio aimed at developers of small
  websites.

7
Microsoft Intermediate Language

Source Code
MSIL
Machine Code
8
Two Technologies

• ADO.NET
• Used for working with data from all sorts of
  sources flat files and databases
• Works on disconnected data sources
• ADO.NET is XML-based so lets you work over the
  Internet, even if the client sits behind a
  firewall
• ASP.NET
• Used for Web-based applications

9
ASP Applications
ASP.NET
Database (SQL Server)
Web Server (IIS)
Browser (IE)
HTML
ADO.NET
10

• Username ATGuest
• Password Tuesday17

11
Validation

• Poor error trapping and handling can turn an
  otherwise good program into a poor one.
• Experience shows that users tend to shy away from
  programs with poor error trapping.
• The effort involved in developing the code to
  trap and handle errors is often a very
  significant part of the overall development
  effort involved in the application.

12
Error Types
Error Types
Data Entry Errors
Runtime Errors
13
Data Entry Validation
Data Entry Validation
Field Validation
Key Validation
Form Validation
14
Best Practice

• Trap all errors (and potential errors)
• Display clear and meaningful messages
• Give direction about what action needs to be
  taken
• Place the cursor in the field that needs changing
• Give users the opportunity to correct errors at
  the earliest possible stage

15
RequiredFieldValidator Control

• Used to specify that users must put information
  into a control
• Checked once a page has been submitted or an
  existing value is changed
• Can be used in conjunction with other validation
  controls
• You can use as many validation controls as you
  wish for a user-entry field

16
RequiredFieldValidator Properties
17
Triggering Validation

• Server-side validation versus client-side
  validation
• Use of the AutoPostBack and CausesValidation
  properties
• Generally best to validate on a Submit button
• Use of the ValidationGroup property for linking
  the Submit button to all the validation controls

18
Other Validation Controls

• Range
• RegularExpression
• Compare
• Custom

19
CustomValidator Code Snippet

• Protected Sub cvrDateStay_ServerValidate(ByVal
  source As Object, ByVal args As
  System.Web.UI.WebControls.ServerValidateEventArgs)
  Handles cvrDateStay.ServerValidate
• Try
• DateTime.ParseExact(args.Value, "d",
  Nothing)
• args.IsValid True
• Catch
• args.IsValid False
• End Try
• End Sub

20
ValidationSummary Control

• Can be used to produce a list of all errors on a
  page
• Set the DisplayMode Property to List, BulletList
  or SingleParagraph
• Checked once a page has been submitted