generate barcode image vb.net MCAD/MCSD Visual C# NET Certification All-in-One Exam Guide in Visual C#.NET

Printer UPC Symbol in Visual C#.NET MCAD/MCSD Visual C# NET Certification All-in-One Exam Guide

MCAD/MCSD Visual C# NET Certification All-in-One Exam Guide
Universal Product Code Version A Generation In Visual C#
Using Barcode printer for .NET framework Control to generate, create UPCA image in .NET framework applications.
UPC Symbol Recognizer In C#
Using Barcode decoder for .NET framework Control to read, scan read, scan image in .NET framework applications.
The Postback Event
Bar Code Encoder In C#
Using Barcode creator for VS .NET Control to generate, create barcode image in .NET framework applications.
Barcode Scanner In C#
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
The server-centric Web Form needs some way to communicate events and data back to the server from the client The way that is handled with ASPNET web pages is with the postback, which returns the data and any events that might have happened on the client since the last postback to the server The benefit behind sending the data from the client to the web server is that between calls to the server we can maintain the information contained in the form on the server In traditional forms, if we switch away from a form and then return, we need to reenter all the information again The postback process ensures that we maintain the state of the form between calls The following example will show the difference between a traditional HTML form and an ASPNET web form The HTML form is built with the following HTML code:
Generate UPC Symbol In VS .NET
Using Barcode printer for ASP.NET Control to generate, create UPC-A Supplement 2 image in ASP.NET applications.
Encode UPCA In .NET Framework
Using Barcode creation for Visual Studio .NET Control to generate, create GTIN - 12 image in Visual Studio .NET applications.
<html> <head> <title>HTML Form</title> </head> <body> <form method="post"> What is you favorite sport <br/> <br/> <input type="radio" value="Football" name="sport">Football<br/> <input type="radio" value="Hockey" name="sport">Hockey<br/> <input type="radio" value="Soccer" name="sport">Soccer<br/> <input type="radio" value="Baseball" name="sport">Baseball<br/> <input type="radio" value="Rugby" name="sport">Rugby<br/> <input type="submit" value="Send selection" onclick="alert('You have clicked the submit button!')"> </form> </body> </html>
Create UPC-A Supplement 2 In Visual Basic .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create UPC A image in VS .NET applications.
Encode Matrix 2D Barcode In Visual C#.NET
Using Barcode maker for Visual Studio .NET Control to generate, create Matrix 2D Barcode image in .NET applications.
We saved this file in the root of our web server (C:\inetpub\wwwroot\) and called the file htmlformhtm Opening the form in the browser allows you to make a selection for your favorite sport, as shown in Figure 13-17 After you click Send Selection, the form clears and appears as in Figure 13-18 The form cleared as we submitted the data to the server This happens because the data is sent to the server and the original page is redrawn; at no point in this process is any state being saved Now we will look at the equivalent form using ASPNET and postback The following ASPNET page (htmlformaspx) will display the same form as the HTML version does, but the state is preserved as we submit the form to the server
Data Matrix 2d Barcode Drawer In Visual C#
Using Barcode maker for .NET Control to generate, create DataMatrix image in Visual Studio .NET applications.
Make Bar Code In Visual C#.NET
Using Barcode generator for .NET Control to generate, create barcode image in .NET framework applications.
<html> <head> <title>HTML Form</title> </head> <body> <form runat="server">
Code 39 Full ASCII Encoder In Visual C#.NET
Using Barcode encoder for VS .NET Control to generate, create Code 39 Full ASCII image in VS .NET applications.
ISSN - 10 Encoder In Visual C#
Using Barcode drawer for .NET Control to generate, create ISSN - 13 image in VS .NET applications.
13: Server-Side Programs and Postback Operations
Encoding Bar Code In .NET
Using Barcode generation for .NET framework Control to generate, create barcode image in .NET applications.
Bar Code Recognizer In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
What is your favorite sport <br/> <br/> <asp:radiobuttonlist id="sport" runat="server"> <asp:listitem id="Football" value="Football" runat="server" /> <asp:listitem id="Hockey" value="Hockey" runat="server" /> <asp:listitem id="Soccer" value="Soccer" runat="server" /> <asp:listitem id="Baseball" value="Baseball" runat="server" /> <asp:listitem id="Rugby" value="Rugby" runat="server" /> </asp:radiobuttonlist> <input type="submit" value="Send selection"> </form> </body> </html>
Bar Code Generation In None
Using Barcode generation for Online Control to generate, create bar code image in Online applications.
Code 39 Creator In None
Using Barcode printer for Font Control to generate, create Code 39 image in Font applications.
The resulting display can be seen in Figure 13-19 After selecting a sport and clicking the button, we still have our selection in the display, showing that the state of the form has been remembered
Recognize Barcode In VS .NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in .NET applications.
UCC-128 Generator In Java
Using Barcode encoder for Eclipse BIRT Control to generate, create EAN 128 image in Eclipse BIRT applications.
PART III
EAN128 Creator In None
Using Barcode generator for Font Control to generate, create USS-128 image in Font applications.
Code 128C Encoder In Java
Using Barcode creator for Java Control to generate, create Code 128 Code Set B image in Java applications.
Figure 13-17
The htmlformhtm page with a selection
MCAD/MCSD Visual C# NET Certification All-in-One Exam Guide
Figure 13-18
The htmlformhtm page after sending the data
To understand what happened and how the selection was remembered, we need to look at the HTML code that the ASPNET process sent to the client browser The following listing is the resulting HTML for the display in Figure 13-19
<html> <head> <title>HTML Form</title> </head> <body> <form name="_ctl0" method="post" action="htmlformaspx" id="_ctl0"> <input type="hidden" name="__VIEWSTATE" value="dDwyMDE0NTgwNzI1Ozs+rR+xbfriVGiHInW3uHd11uisuj4=" /> What is your favorite sport <br/> <br/> <table id="sport" border="0"> <tr> <td><input id="sport_0" type="radio" name="sport" value="Football" /> <label for="sport_0">Football</label></td> </tr><tr> <td><input id="sport_1" type="radio" name="sport" value="Hockey" /> <label for="sport_1">Hockey</label></td> </tr><tr> <td><input id="sport_2" type="radio" name="sport" value="Soccer"
13: Server-Side Programs and Postback Operations
checked="checked" /> <label for="sport_2">Soccer</label></td> </tr><tr> <td><input id="sport_3" type="radio" name="sport" value="Baseball" /> <label for="sport_3">Baseball</label></td> </tr><tr> <td><input id="sport_4" type="radio" name="sport" value="Rugby" /> <label for="sport_4">Rugby</label></td> </tr> </table> <input type="submit" value="Send selection"> </form> </body> </html>
As you can see, the radiobuttonlist from the htmlformaspx listing was turned into a table with standard HTML radio input elements The highlighted portions of the HTML code are what make ASPNET s postback work The hidden control with the name __VIEWSTATE and the binary value "dDwyMDE0NTgwNzI1Ozs+rR+xbfriVGiHInW3uHd11uisuj4=" is the key The value of the __VIEWSTATE control is the binary representation (hash) of the form, and it is the comparison between the original version of the form, as represented by the
Copyright © OnBarcode.com . All rights reserved.