.NET Fundamentals ASP.NET - Web Forms December 8, 2003

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.NET FundamentalsASP.NET - Web FormsDecember
8, 2003
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Agenda December 8, 2003

• Homework Questions
• Quick Note on Namespaces
• ASP.NET Web Applications
• Simple WebTime Class Exercise
• Web Form GuestBook Class Exercise
• Homework Assignment for December 11, 2000

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Topics

• Quick Note on Namespaces
• ASP.NET Technology
• ASP.NET Web Applications in Visual Studio
• Visual Studio .NET Software Requirements
• Internet Information Services (IIS)
• Web-Based Application Development
• ASP.NET Web Applications in Visual Studio
• Things To Look For When Creating a .NET Web Form
  Project
• WebTime Class Exercise
• Web Forms Events
• Web Controls
• Web Form Database Applications
• GuestBook Database Class Exercise
• Local versus Web Project
• Deploying Web Applications
• Tic Tac Toe Homework Problem

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Namespaces

• Arbitrary grouping
• Can be more than one file
• Contains at least one class file
• Identified with a using statement in C
• Simplifies class declarations
• Much freedom in naming (see below)
• using System.Microsoft.Chips.GuestBookDB

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ASP.NET Technology
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ASP.NET Technology

• Web Forms pages are built with ASP.NET
  technology.
• ASP.NET is a unified Web platform that provides
  all the services necessary for you to build
  enterprise-class applications.
• ASP.NET, in turn, is built on the .NET Framework,
  so the entire framework is available to any
  ASP.NET application.
• Your applications can be authored in any language
  compatible with the common language runtime,
  including Microsoft Visual Basic, Visual C, and
  JScript .NET.

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ASP.NET Page Framework and the Web Forms Page

• The ASP.NET page framework is a programming
  framework that runs on a Web server to
  dynamically produce and manage Web Forms pages.
• In Visual Studio, Web Forms provides a forms
  designer, editor, controls, and debugging, which
  together allow you to rapidly build server-based,
  programmable user interfaces for browsers and Web
  client devices.
• Web Forms pages run on any browser or client
  device. However, you can design your Web Forms
  page to target a specific browser, such as
  Microsoft Internet Explorer 5, and take
  advantage of the features of a specific browser
  or client device.

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ASP.NET Page Framework and the Web Forms Page

• The ASP.NET page framework creates an abstraction
  of the traditional client-server Web interaction
  so that you can program your application using
  traditional methods and tools that support rapid
  application development (RAD) and object-oriented
  programming (OOP).
• Within Web Forms pages you can work with HTML
  elements using properties, methods, and events.
• The ASP.NET page framework removes the
  implementation details of the separation of
  client and server inherent in Web-based
  applications by presenting a unified model for
  responding to client events in code that runs at
  the server.

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ASP.NET Page Framework and the Web Forms Page

• The framework also automatically maintains the
  state of a page and the controls on that page
  during the page processing life cycle.
• The ASP.NET page framework and Web Forms pages
  also support server controls that encapsulate
  common UI functionality in easy-to-use, reusable
  controls.
• ASP.NET supports mobile controls for Web-enabled
  devices such as cellular phones, handheld
  computers, and personal digital assistants
  (PDAs).

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XML Web Services

• ASP.NET supports XML Web services.
• An XML Web service is a component containing
  business functionality exposed through Internet
  protocols.
• An XML Web service enables applications to
  exchange information between Web-based
  applications using standards like HTTP and XML
  messaging to move data across firewalls.
• XML Web services are not tied to a particular
  component technology or object-calling
  convention. As a result, programs written in any
  language, using any component model, and running
  on any operating system can access XML Web
  services.

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State Management Facilities

• ASP.NET provides intrinsic state management
  functionality that allows you to save and manage
  application-specific, session-specific, and
  developer-defined information. This information
  can be independent of any controls on the page.
  It can be shared between pages, such as customer
  information or the contents of a shopping cart.
• ASP.NET offers distributed state facilities. You
  can create multiple instances of the same
  application on one computer or on several
  computers.

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Application Events

• ASP.NET allows you to include application-level
  event-handling code in the optional global.asax
  file. You can use application events to manage
  application-wide information and perform orderly
  application startup and cleanup tasks.

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Compilation

• All ASP.NET code, including server scripts, is
  compiled, which allows for strong typing,
  performance optimizations, and early binding,
  among other benefits. Once the code has been
  compiled, the runtime further compiles ASP.NET to
  native code, providing improved performance.
• Note  Web Forms pages, XML Web services, and
  components are compiled into dynamic-link library
  (.dll) files. Once compiled, these files do not
  need to be registered on the Web server on which
  they run.

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Configuration

• ASP.NET configuration settings are stored in
  XML-based files. Since these XML files are ASCII
  text files, you can read and modify them, so it
  is simple to make configuration changes to your
  Web applications. Each of your applications can
  have its own configuration file and you can
  extend the configuration scheme to suit your
  requirements.

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Deployment

• Visual Studio provides a simplified mechanism for
  deploying applications to local or remote
  servers. You can install files by simply copying
  them to your specified application directories,
  or by using a more specialized and configurable
  deployment project.

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Security

• When an ASP.NET application runs, it executes in
  the context of a special local user on the Web
  server, called ASPNET, with limited permissions.
  This enhances the security of your Web
  application code by restricting its access to
  Windows resources and processes.
• ASP.NET also provides various authorization and
  authentication schemes for Web applications. You
  can easily remove, add to, or replace these
  schemes depending upon the needs of your
  application.

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ASP.NET Web Applications in Visual Studio
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ASP.NET Web Applications in Visual Studio

• Visual Studio .NET allows you to create
  applications that leverage the power of the World
  Wide Web.
• This includes everything from
• a traditional Web site that serves HTML pages,
• to fully featured business applications that run
  on an intranet or the Internet,
• to sophisticated business-to-business
  applications providing Web-based components that
  can exchange data using XML.

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Visual Studio ASP.NET Web Applications

• ASP.NET is part of the .NET Framework, so that it
  provides access to all of the framework features.
• Create ASP.NET Web applications using any .NET
  programming language (Visual Basic, C, Managed
  Extensions for C, and many others) and .NET
  debugging facilities.
• Access data using ADO.NET.
• Access operating system services using .NET
  Framework classes, and so on.

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Visual Studio ASP.NET Web Applications

• ASP.NET Web applications run on a Web server
  configured with Microsoft Internet Information
  Services (IIS). However, you do not need to work
  directly with IIS. You can program IIS facilities
  using ASP.NET classes, and Visual Studio handles
  file management tasks such as creating IIS
  applications when needed and providing ways for
  you to deploy your Web applications to IIS.

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Where Does Visual Studio Fit In?

• As with any .NET application, if you have the
  .NET Framework, you can create ASP.NET
  applications using text editors, a command-line
  compiler, and other simple tools. You can copy
  your files manually to IIS to deploy the
  application.
• Alternatively, you can use Visual Studio. When
  you use Visual Studio to create Web applications,
  you are creating essentially the same application
  that you could create by hand. That is, Visual
  Studio does not create a different kind of Web
  application the end result is still an ASP.NET
  Web application.

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Where Does Visual Studio Fit In?

• The advantage of using Visual Studio is that it
  provides tools that make application development
  much faster, easier, and more reliable. These
  tools include
• Visual designers for Web pages with drag-and-drop
  controls and code (HTML) views with syntax
  checking.
• Code-aware editors that include statement
  completion, syntax checking, and other
  IntelliSense features.
• Integrated compilation and debugging.
• Project management facilities for creating and
  managing application files, including deployment
  to local or remote servers.

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Visual Studio .NET Software Requirements
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Visual Studio .NET Software Requirements

• Certain project types and features in Visual
  Studio require that specific software components,
  which may be listed as optional in setup, must be
  installed before you can use that feature or
  project. Some of these components must be
  installed on the development computer, while
  others can be installed on a remote computer.

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Identifying Software Requirement Issues

• The following table lists the components that
  must be installed on the various operating
  systems to perform the tasks specified. These
  components are not installed with Visual
  Studio .NET Prerequisites.

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Visual Studio .NET Software Requirements
Do you want to Windows 2000 Windows XPWindows Server 2003 or later Windows Server 2003 or later Windows NT41Windows 98Windows MeWindows XP Home
Develop ASP Web applications and XML Web services Internet Information Services (IIS) Internet Information Services (IIS) Not supported
Compile code related to Microsoft Windows Message Queuing (MSMQ) Message Queuing Services Message Queuing Services Not supported
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Visual Studio .NET Software Requirements
Do you want to Windows 2000 Windows XPWindows Server 2003 or later Windows Server 2003 or later Windows NT41Windows 98Windows MeWindows XP Home
Debug code on remote computers Visual Studio Remote Debugger Visual Studio Remote Debugger Visual Studio Remote Debugger
Use source code control to version stored procedures Visual Studio 6.0 Stored Procedure VersioningVisual SourceSafeMicrosoft SQL Server Visual Studio 6.0 Stored Procedure VersioningVisual SourceSafeMicrosoft SQL Server Not supported
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Internet Information Services (IIS)
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Internet Information Services (IIS)

• Internet Information Services (IIS) 6.0 is a
  powerful Web server, available in all versions of
  Microsoft Windows Server 2003, which provides a
  highly reliable, manageable, scalable, and secure
  Web application infrastructure.
• IIS 6.0 enables organizations of all sizes to
  quickly and easily deploy Web sites and provides
  a high-performance platform for applications
  built using Microsoft ASP.NET and the Microsoft
  .NET Framework.

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Web-Based Application Development
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Web-Based Application Development

• Creates Web content for Web browser clients
• HyperText Markup Language (HTML)
• Client-side scripting
• Images and binary data
• Web Forms (Web Form pages)
• File extension .aspx
• aspx (Web Form files) contain written code, event
  handlers, utility methods and other supporting
  code
• .aspx.cs C.NET code behind page

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Simple HTTP Transaction

• HyperText Transfer Protocol (HTTP)
• Defines methods and headers which allows clients
  and servers exchange information in uniform way
• Uniform Resource Locator (URL)
• IP address indicating the location of a resource
• All HTML documents have a corresponding URL
• Domain Name Server (DNS)
• A computer that maintains a database of hostnames
  and their corresponding IP addresses

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System Architecture

• Multi-tier Applications
• Web-based applications (n-tier applications)
• Tiers are logical groupings of functionality
• Application Client or User Tier (top level tier)
• User Browser Interface to the Application
• Information Tier (data tier or bottom tier)
• Maintains data pertaining to the applications
• Usually stores data in a relational database
  management systems (RDBMS)
• Middle Tier
• Acts as an intermediary between data in the
  information tier and the application's clients

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Creating and Running a Simple Web-Form Example

• Visual Component
• Clickable buttons and other GUI components which
  users interact
• Nonvisual Component
• Hidden inputs that store any data that document
  author specifies such as e-mail address

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.NET Frameworks Requires

• Internet Information Services (IIS)
• FrontPage Server Extensions (FPSE)
• See ?Visual Studio .NET Software Requirements
  help text
• Not available on
• Windows NT4
• Windows 98
• Windows Me
• Windows XP Home

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Things To Look For When Creating a .NET Web Form
Project
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Things To Look For When Creating a .NET Web Form
Project

• The project location is split
• Project Files ? C\inetput\wwwroot\ project name
• Solution Files ? C\Documents and Settings\...\My
  Documents\Visual Studio Projects\ project name
• Browser Reference
• http//localhost/ project name
• C\inetpub\wwwroot\ project name

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Project Files

• Many Project Files and File Types located in
• C\Inetpub\wwwroot\Week7\WebTime\
• Global.asax, Global.asax.cs, Global.asax.resx
• Web.Config
• WebForm1.aspx ? Windows Form Equivalent
• WebForm1.aspx.cs ? Code Behind File
• WebForm1.aspx.resx
• or for Visual Basic.NET
• WebTime.aspx, WebTime.aspx.vb, WebForm1.aspx.resx

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Web Forms Pages and Projects in Visual Studio

• To work with a Web Forms page in Visual Studio,
  you use the Web Forms Designer.
• The designer includes a WYSIWYG view, called
  Design view, for laying out the elements of the
  page.
• Alternatively, you can switch the designer to
  HTML view, which gives you direct access to the
  ASP.NET syntax of the elements on the page.
• Finally, the designer includes a code editor with
  Intellisense that you can use to create the page
  initialization and event handler code for your
  page.

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Project Files Created With Web Forms

• When you create a Web project, Visual Studio
  constructs a Web application directory structure
  on the target Web server, and a project structure
  on your local computer.
• Note   You need to have appropriate privileges on
  the Web server computer to create and manage Web
  application files. The correct way to get those
  privileges is to be a member of the VS Developers
  group that is automatically created on the Web
  server.

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Project Files Created With Web Forms
File Created Description
WebForm1.aspx and WebForm1.aspx.vb files (or WebForm1.aspx.cs for Visual C Web applications) These two files make up a single Web Forms page. The .aspx file contains the visual elements of the Web Forms page, for example HTML elements and Web Forms controls. The WebForm1.aspx.vb class file is a hidden, dependent file of WebForm1.aspx. It contains the code-behind class for the Web Forms page, containing event-handler code and the like.
AssemblyInfo.vb (for Visual Basic projects) or AssemblyInfo.cs (for C projects) A project information file (AssemblyInfo.vb or AssemblyInfo.cs file) that contains metadata about the assemblies in a project, such as name, version, and culture information. For details on data contained in the assembly file, see Assembly Manifest.
Web.config An XML-based file that contains configuration data on each unique URL resource used in the project. For more information see Application Configuration Files.
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Project Files Created With Web Forms
File Created Description
Global.asax and Global.vb or Global.cs files An optional file for handling application-level events. This file resides in the root directory of an ASP.NET application. The Global.vb class file is a hidden, dependent file of Global.asax. It contains the code for handling application events such as the Application_OnError event. At run time, this file is parsed and compiled. For more information on Global.asax file usage, see Global.asax File.
Styles.css A cascading style sheet file to be used within the project. For more information see Introduction to Cascading Style Sheets.
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Solution Files

• Found in a Separate Directory
• C\Documents and Settings\...\My Documents\Visual
  Studio Projects\ project name
• Visual Studio.Solution (.sln file type)
• WebTime.sln
• Solution User Options (.suo file type)
• WebTime.suo

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Visual Studio .NET uses two file types (.sln and
.suo) to store settings specific to solutions.
These files, known collectively as solution
files, provide Solution Explorer with the
information it needs to display a graphical
interface for managing your files. They allow you
to concentrate on your projects and final goals
rather than on the environment itself each time
you return to your development tasks.
Solution Files (.sln and .suo)
Extension Name Description
.sln Visual Studio.Solution Organizes projects, project items and solution items into the solution by providing the environment with references to their locations on disk.
.suo Solution User Options Records all of the options that you might associate with your solution so that each time you open it, it includes customizations that you have made.
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WebTime Class Exercise
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WebTime Class Exercise

• Create a new ASP.NET Web Application (using C)
• Add a label for the Title WebTime
• Add a label for the time (i.e.
  DateTime.Now.ToString)
• Set the font size on the above to XX-Large
• Add a Button to refresh the time
• and a little code

• private void Button1_Click(object sender,
  System.EventArgs e)
• Label2.Text DateTime.Now.ToString()

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Web Form Events
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Web Form Events

• Event an object that encapsulates the idea that
  something has happened.
• Events are generated or raised (i.e. when a
  button is clicked)
• Event Handler method that responds to the
  event. Event handles are written is C in the
  code-behind page.
• Event handlers are delegates

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Event Handles

• Return a void
• Two parameters
• Object raising the event
• Event arguments object of type EventArgs that
  can expose properties specific to that event
  type.

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Types of Events

• Local events mouseover, button clicks, text
  changes
• Server handled events, requiring a "round trip".
• Postback events cause the form to be posted back
  to the server immediately, including type events,
  such as Button Click event.
• Non-postback events are cached by the control
  until the next postback event occurs. You can
  override this non-postback behavior by setting a
  controls AutoPostBack property to true.

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Events and Delegates

• An event is a message sent by an object to signal
  the occurrence of an action.
• The action could be caused by user interaction,
  such as a mouse click, or it could be triggered
  by some other program logic.
• The object that raises (triggers) the event is
  called the event sender.
• The object that captures the event and responds
  to it is called the event receiver.

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Events and Delegates

• In event communication, the event sender class
  does not know which object or method will receive
  (handle) the events it raises.
• What is needed is an intermediary (or
  pointer-like mechanism) between the source and
  the receiver.
• The .NET Framework defines a special type
  (Delegate) that provides the functionality of a
  function pointer.

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Events and Delegates

• A delegate is a class that can hold a reference
  to a method.
• Unlike other classes, a delegate class has a
  signature, and it can hold references only to
  methods that match its signature.
• A delegate is thus equivalent to a type-safe
  function pointer or a callback.
• While delegates have other uses, the discussion
  here focuses on the event handling functionality
  of delegates. The following example shows an
  event delegate declaration.

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Event Delegate Declaration.

• button1_Click - the delegate for the button
  event.
• EventArgs - the class that holds event data for
  the alarm event. Actually System.EventArgs.
• private delegate void button1_Click(object
  sender, EventArgs e)
• The syntax is similar to that of a method
  declaration however, the delegate keyword
  informs the compiler that button1_Click is a
  delegate type.
• By convention, event delegates in the .NET
  Framework have two parameters, the source that
  raised the event and the data for the event.

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Delegate

• Note   A delegate declaration is sufficient to
  define a delegate class.
• The declaration supplies the signature of the
  delegate, and the common language runtime
  provides the implementation.
• An instance of the delegate can bind to any
  method that matches its signature.

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Web Controls
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Web vs Windows Controls
Windows Controls Web Controls
Label Label
TextBox TextBox
Button Button
RadioButton RadioButton
GroupBox GroupBox
ComboBox DropDownList
DataGrid DataGrid



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Web Controls
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AdRotator Control

• Randomly selects an image to display and then
  generates a hyperlink to the Web page associated
  with that image

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20.5 AdRotator
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Web Form Database Applications
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Database Insert Command

• Map a list of values to a list of the fields to
  be updated.
• INSERT INTO TableName(list of columns)
  VALUES(corresponding list of data values)

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Database Insert Command

• INSERT INTO Messages(EmailAddress, FirstName,
  LastName, Message, MessageDate) VALUES
  (cas_at_pv.com,John,Smith,Hi to me,
  10/21/2003 123416 PM)

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Database Insert Command

• INSERT INTO Messages(EmailAddress, FirstName,
  LastName, Message, MessageDate) " _
• "VALUES ('" _
• TextBox3.Text "', '" TextBox1.Text
  "', '" _
• TextBox2.Text "', '" TextBox4.Text
  "', '" mTime.Now.Today " "
  mTime.Now.ToLongTimeString "')"

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Differences from Windows Forms

• Populating a Data Grid
• Windows Form
• dg.SetDataBinding(ds, "Books")
• dg.Show()
• Web Form
• dg.DataSource objDS
• dg.DataBind()

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Debugging Web Form Applications

• No MessageBox for error messages
• Use Response.Write to display messages
• Use a label or TextBox to display messages
• Enable Tracing

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GuestBook Database Class Exercise
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Tracing
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ASP.NET Tracing

• ASP.NET introduces new functionality that allows
  you to view diagnostic information about a single
  request for an ASP.NET page simply by enabling it
  for your page or application.
• Tracing allows you to write debug statements
  directly in your code without having to remove
  them from your application when it is deployed to
  production servers. You can write variables or
  structures in a page, assert whether a condition
  is met, or simply trace through the execution
  path of your page or application.

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ASP.NET Tracing

• In order for these messages and other tracing
  information to be gathered and displayed, you
  must enable tracing for the page or application.
  When you enable tracing, two things occur
• ASP.NET appends a series of diagnostic
  information tables immediately following the
  page's output. The information is also sent to a
  trace viewer application (if you have enabled
  tracing for the application).
• ASP.NET displays your custom diagnostic messages
  in the Trace Information table of the appended
  performance data.

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ASP.NET Tracing

• Diagnostic information and tracing messages that
  you specify are appended to the output of the
  page that is sent to the requesting browser.
  Optionally, you can view this information from a
  separate trace viewer (Trace.axd) that displays
  trace information for every page in a given
  application. This information can help you to
  clarify errors or undesired results as ASP.NET
  processes a page request.
• Trace statements are processed and displayed only
  when tracing is enabled. You can control whether
  tracing is displayed to a page, to the trace
  viewer, or both.

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Tracing
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Tracing
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Local versus Web Project
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Local versus Web Project

• Factors to consider when deciding between a local
  or Web project model.
• Installation strategy
• Impact of workload

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Installation strategy

• Quick-deploying application on a server with
  minimal client configuration, the Web project
  model is best. You can install and run this
  project on the server without installing support
  files on each client, and make upgrades only on
  the server
• Projects that have little server involvement or
  for stand-alone applications, a local project
  model is the better choice. In this scenario,
  upgrades can be completed on each individual
  client computer.

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Impact of workload

• Web projects offer a server-based strategy where
  the majority of operations are conducted on the
  server. The client computer uses a Web browser to
  send information to and display information from
  the server-side application.
• If server resources are limited, then use a local
  project model where the work is done on the
  client computer without consuming precious server
  time.

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The following table gives a side-by-side
comparison of Web projects and local projects in
both the design and working environments
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Consideration Web project Local project
File storage during development Files are stored at a specified URL on a computer with Internet Information Services (IIS) installed. The project also keeps a temporary cache of files on client computers for working offline. Project files are stored on the local computer.
Build model when developing Application code is compiled as a DLL and run on the server. Results are seen on the client computer. Code is compiled and run on the client computer.
Deployment method The project is deployed to a Web server. Project files are installed on the client computer with required support files.
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Consideration Web project Local project
Workload Client computers run the application remotely with a Web browser. Processing is done primarily on the server. The application is run locally on the client computer.
Upgrading Application changes are made at the server level without installation of support files on client computers. The application upgrades are installed on client computers.
Moving project files The Copy Project command is used to move files to the specified URL. Project files are physically copied from one location to another.
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Deploying Web Applications
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Deploying Web Applications

• Microsoft ASP.NET applications can take
  advantage of many different technologies, such as
  private and shared assemblies, interoperation
  with COM and COM, event logs, message queues,
  and so on.
• An ASP.NET application is defined as all the Web
  pages (.aspx and HTML), handlers, modules,
  executable code, and other (such as images and
  configuration) that can be invoked from a virtual
  directory and its subdirectories on a Web server.
• An ASP.NET application includes the project DLL
  (if the code-behind features of .aspx are used)
  and typically other assemblies that are used to
  provide functionality for the application. These
  assemblies are located in the bin folder
  underneath the virtual directory of the
  application.

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Deploying ASP.NET Application

• The Microsoft .NET Framework makes deployment of
  Web applications much easier than before.
• Configuration settings can be stored in a
  configuration file (Web.config), which is a text
  file based on Extensible Markup Language
  (XML)these settings can be modified after the
  Web application is deployed without requiring the
  Web solution to be recompiled.

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Deploying ASP.NET Application

• ASP.NET allows changes to be made to assemblies
  without requiring that the Web server be stopped
  and restarted.
• When a newer version of a Web.config, .aspx,
  .asmx, or other ASP.NET file is copied to an
  existing Web application, ASP.NET detects that
  the file has been updated. It then loads a new
  version of the Web application to handle all new
  requests, while allowing the original instance of
  the Web application to finish responding to any
  current requests. After all requests are
  satisfied for the original application, it is
  automatically removed. This feature eliminates
  downtime while updating Web applications.

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Deploying ASP.NET Application

• There are a number of different ways for
  deploying all of these elements from your
  development or test environment to the production
  Web server(s).
• For simple Web applications, it is often
  appropriate to copy the files to the target
  computer, using XCOPY, Microsoft Windows
  Explorer, FTP, or the Microsoft Visual Studio
  .NET development system Copy Project command on
  the Project menu.
• For more complex solutions, such as those that
  include shared assemblies or those that rely on
  specific Microsoft Internet Information Services
  (IIS) settings to be in place, using Windows
  Installer technology might be a better choice.

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Tic Tac ToeHomework Assignment
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