Academic Tutorials

English | French | Portugese | German | Italian
Home Advertise Payments Recommended Websites Interview Questions FAQs
News Source Codes E-Books Downloads Jobs Web Hosting

Introduction to VB.NET
Visual Basic Scripts
Variables and Data Types
Arrays and Collections
Arithmetic and String Operations
Relational and Logical Operations
Math and String Functions
Date and Time Functions
Display Formats
The If Statement
The If...Else Statement
The Else...If Statement
The Select...Case Statement
The For...Next Statement
The For Each...Next Statement
The While...End While Statement
The Do...Loop Statement

HTML Tutorials
HTML Tutorial
XHTML Tutorial
CSS Tutorial
TCP/IP Tutorial
CSS 1.0
CSS 2.0
XML Tutorials
XML Tutorial
XSL Tutorial
XSLT Tutorial
DTD Tutorial
Schema Tutorial
XForms Tutorial
XSL-FO Tutorial
XML DOM Tutorial
XLink Tutorial
XQuery Tutorial
XPath Tutorial
XPointer Tutorial
RDF Tutorial
SOAP Tutorial
WSDL Tutorial
RSS Tutorial
WAP Tutorial
Web Services Tutorial
Browser Scripting
JavaScript Tutorial
VBScript Tutorial
DHTML Tutorial
HTML DOM Tutorial
WMLScript Tutorial
E4X Tutorial
Server Scripting
ASP Tutorial
PERL Tutorial
SQL Tutorial
ADO Tutorial
Apple Script
PL/SQL Tutorial
SQL Server
.NET (dotnet)
.Net Mobile
C# : C Sharp
SVG Tutorial
Flash Tutorial
Media Tutorial
SMIL Tutorial
Photoshop Tutorial
Gimp Tutorial
Gnuplot Programming
GIF Animation Tutorial
Scientific Visualization Tutorial
Web Building
Web Browsers
Web Hosting
W3C Tutorial
Web Building
Web Quality
Web Semantic
Web Careers
Weblogic Tutorial
Web Site Hosting
Domain Name
Java Tutorials
Java Tutorial
JSP Tutorial
Servlets Tutorial
Struts Tutorial
EJB Tutorial
JMS Tutorial
JMX Tutorial
Programming Langauges
C Tutorial
C++ Tutorial
Visual Basic Tutorial
Data Structures Using C
Assembly Language
Forth Programming
Lisp Programming
Data Warehousing
CGI Programming
Emacs Tutorial
Soft Skills
Communication Skills
Time Management
Project Management
Team Work
Leadership Skills
Corporate Communication
Negotiation Skills
Database Tutorials
Operating System
Software Testing
SAP Module
Business Warehousing
SAP Basis
Material Management
Sales & Distribution
Human Resource
Customer Relationship Management
Production and Planning
Networking Programming
Corba Tutorial
Networking Tutorial
Microsoft Office
Microsoft Word
Microsoft Outlook
Microsoft PowerPoint
Microsoft Publisher
Microsoft Excel
Microsoft Front Page
Microsoft InfoPath
Microsoft Access
Financial Accounting
Managerial Accounting
Network Sites


Previoushome Next


Within a subprogram, one of the primary ways in which Visual Basic code is packaged on a Web page, variously call a subroutine or procedure. A subprogram has following general structure:


Sub name (signature)


End Sub

A subprogram is identified by the keyword Sub at its beginning and the keywords End Sub at its end and a subprogram name is a programmer-supplied name that follows Visual Basic naming conventions. The name must be unique among the collection of subprograms on the page. Visual Basic commands, or statements, are enclosed inside the subprogram to carry out the processing for which the subprogram is created.

A subprogram may or may not require a signature and a signature is a list of variables, called arguments, that are supplied to the subprogram in order for it to carry out its processing. Various types of signatures are given below.

Inside <script> tags with the attribute runat="server",all subprograms must be contained.Inside a single pair of <script> tags,any number of subprograms can be contained.

The Page_Load Subprogram

Subprograms are activated to perform their processing in several ways and one of the ways is to activate the subprogram every time the Web page is accessed, and prior to sending the page to the client who made the request. This particular subprogram has the required name Page_Load and it does not have a signature, although a pair of empty parentheses can be coded to indicate its absence: Page_Load().

The Page_Load subprogram is not required unless there is processing to take place every time the page opens and it might, for instance, decide to display the current date on your page. In this case to retrieve the system date from the server,the Page_Load subprogram would be an appropriate place and place it in an output control on the page, prior to sending the page to the browser.

Sub Page_Load

DateOut.Text = DateString()

End Sub


<p>Today is <asp:Label id="DateOut" runat="server"/></p>


Other common uses for the Page_Load subprogram are to populate drop-down lists,checkboxes, and radio buttons that appear on the page, or to access a set of records from a database for display on the page.

The Page.IsPostBack Condition

Every time the page loads or is refreshed,statements that appear in the Page_Load subprogram are run. Often times, however, it is necessary to perform the processing only the first time the page loads and this is common practice under ASP.NET where page controls automatically retain their values between post-backs of the page (when the page is reloaded due to an action of the user). All controls take part in page's View State and their values are retained between page postings.

As it has illustrated in the above example,this need to run a script only the first time the page loads and since the system date is assigned to an <asp:Label> control, the value of the control will be displayed and retained if the page is posted back to the server through some user action. It is not necessary every time the page loads to get the system date.

For these situations, script statements are placed inside a Page.IsPostBack condition test and they are executed only the first time the page loads and a server control is populated with the information generated by the script and subsequently, the control retains its information without having to repopulate it.

<SCRIPT runat="server">

Sub Page_Load

If Not Page.IsPostBack Then

DateOut.Text = DateString()

End If

End Sub

Calling Subprograms from Controls

In most cases,by server controls subprograms are called upon to do their work through explicit subprogram calls. Various controls have various ways of passing information to it and calling a subprogram.

A common way for a page control to call a subprogram is through its OnClick="subprogram" event handler and naming a subprogram to run when the user clicks the control.As for example, a button control,

<asp:Button OnClick="subprogram" runat="server"/>

displays a standard button on the page and when the user clicks the button, the named subprogram is run

Subprogram Signatures

Subprograms that are called from server controls have special signatures depending on which event handler makes the call and what type of control. These signatures are in the general format shown below.

The table below gives the argument type for the server controls that call a subprogram through their various event handlers.

Control Argument Type
OnClick subprogram call
arguments As EventArgs
OnCommand subprogram call
arguments As CommandEventArgs
OnTextChanged subprogram call
arguments As EventArgs
OnCheckedChanged subprogram call
arguments As EventArgs
OnSelectedIndexChanged subprogram call
arguments As EventArgs
OnItemCommand subprogram call
arguments As RepeaterCommandEventArgs
arguments As DataGridCommandEventArgs
arguments As DataListCommandEventArgs
OnSortCommand subprogram call
arguments As DataGridSortCommandEventArgs

Accessing Passed Arguments

As a simple example of the kinds of information available through a subprogram's signature and take the case of a standard button that calls a subprogram through its OnCommand event handler.

<SCRIPT runat="server">

Sub MySubprogram (Src As Object, Args As CommandEventArgs)

Identity.Text =
CommandName.Text = Args.CommandName
End Sub


<asp:Button id="MyButton" runat="server"
CommandName="Do My Processing"/></p>

Source Id = <asp:Label id="ID" runat="server"/><br/>
Command Name = <asp:Label id="CommandName" runat="server"/><br/>

Be the first one to comment on this page.

  VB.NET eBooks
More Links » »
More Links » »
 VB.NET Interview Questions
More Links » »
 VB.NET Articles
More Links » »
 VB.NET News
More Links » »
 VB.NET Jobs
More Links » »

Share And Enjoy:These icons link to social bookmarking sites where readers can share and discover new web pages.
  • blinkbits
  • BlinkList
  • blogmarks
  • co.mments
  • connotea
  • digg
  • Fark
  • feedmelinks
  • Furl
  • LinkaGoGo
  • Ma.gnolia
  • NewsVine
  • Netvouz
  • RawSugar
  • Reddit
  • scuttle
  • Shadows
  • Simpy
  • Smarking
  • Spurl
  • TailRank
  • Wists
  • YahooMyWeb

Previoushome Next

Keywords: Subprograms using VB.NET, using source code, c++ using, sql using, using syntax, c# using, oracle using, using statement, c using, using programming, using function, select using, java using, using string, using object, update using, using code, using command

HTML Quizzes
CSS Quiz
CSS 1.0 Quiz
CSS 2.0 Quiz
XML Quizzes
XML Quiz
XSL Quiz
DTD Quiz
Schema Quiz
XForms Quiz
XLink Quiz
XQuery Quiz
XPath Quiz
XPointer Quiz
RDF Quiz
RSS Quiz
WAP Quiz
Web Services Quiz
Browser Scripting Quizzes
JavaScript Quiz
VBScript Quiz
WMLScript Quiz
E4X Quiz
Server Scripting Quizzes
ASP Quiz
SQL Quiz
ADO Quiz
CVS Quiz
Python Quiz
Apple Script Quiz
SQL Server Quiz
PHP Quiz
.NET (dotnet) Quizzes
Microsoft.Net Quiz
ASP.Net Quiz
.Net Mobile Quiz
C# : C Sharp Quiz
VC++ Quiz
Multimedia Quizzes
SVG Quiz
Flash Quiz
Media Quiz
Photoshop Quiz
Gimp Quiz
Matlab Quiz
Gnuplot Programming Quiz
GIF Animation Quiz
Scientific Visualization Quiz
Graphics Quiz
Web Building Quizzes
Web Browsers Quiz
Web Hosting Quiz
W3C Quiz
Web Building Quiz
Web Quality Quiz
Web Semantic Quiz
Web Careers Quiz
Weblogic Quiz
SEO Quiz
Web Site Hosting Quiz
Domain Name Quiz
Java Quizzes
Java Quiz
JSP Quiz
Servlets Quiz
Struts Quiz
EJB Quiz
JMS Quiz
JMX Quiz
Eclipse Quiz
J2ME Quiz
Programming Langauges Quizzes
C Quiz
C++ Quiz
Visual Basic Quiz
Data Structures Using C Quiz
Cobol Quiz
Assembly Language Quiz
Mainframe Quiz
Forth Programming Quiz
Lisp Programming Quiz
Pascal Quiz
Delphi Quiz
Fortran Quiz
OOPs Quiz
Data Warehousing Quiz
CGI Programming Quiz
Emacs Quiz
Gnome Quiz
ILU Quiz
Soft Skills Quizzes
Communication Skills Quiz
Time Management Quiz
Project Management Quiz
Team Work Quiz
Leadership Skills Quiz
Corporate Communication Quiz
Negotiation Skills Quiz
Database Quizzes
Oracle Quiz
MySQL Quiz
Operating System Quizzes
BSD Quiz
Symbian Quiz
Unix Quiz
Internet Quiz
IP-Masquerading Quiz
IPC Quiz
Software Testing Quizzes
Testing Quiz
Firewalls Quiz
SAP Module Quizzes
ERP Quiz
Business Warehousing Quiz
SAP Basis Quiz
Material Management Quiz
Sales & Distribution Quiz
Human Resource Quiz
Netweaver Quiz
Customer Relationship Management Quiz
Production and Planning Quiz
Networking Programming Quizzes
Corba Quiz
Networking Quiz
Microsoft Office Quizzes
Microsoft Word Quiz
Microsoft Outlook Quiz
Microsoft PowerPoint Quiz
Microsoft Publisher Quiz
Microsoft Excel Quiz
Microsoft Front Page Quiz
Microsoft InfoPath Quiz
Microsoft Access Quiz
Accounting Quizzes
Financial Accounting Quiz
Managerial Accounting Quiz
Testimonials | Contact Us | Link to Us | Site Map
Copyright ? 2008. Academic All rights reserved Privacy Policies | About Us
Our Portals : Academic Tutorials | Best eBooksworld | Beyond Stats | City Details | Interview Questions | Discussions World | Excellent Mobiles | Free Bangalore | Give Me The Code | Gog Logo | Indian Free Ads | Jobs Assist | New Interview Questions | One Stop FAQs | One Stop GATE | One Stop GRE | One Stop IAS | One Stop MBA | One Stop SAP | One Stop Testing | Webhosting in India | Dedicated Server in India | Sirf Dosti | Source Codes World | Tasty Food | Tech Archive | Testing Interview Questions | Tests World | The Galz | Top Masala | Vyom | Vyom eBooks | Vyom International | Vyom Links | Vyoms | Vyom World | Important Websites
Copyright ? 2003-2021 Vyom Technosoft Pvt. Ltd., All Rights Reserved.