Another Look at the Code

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Sams Teach Yourself ASP.NET in 21 Days, Second Edition
By Chris Payne
Table of Contents
Day 2.  Building ASP.NET Pages


Now that you have a better understanding of how ASP.NET works, let's take another look at the code from the beginning of today's lesson, as shown in Listing 2.8.

Listing 2.8 Your First VB.NET ASP.NET Page Revisited
 1:    <%@ Page Language="VB" %> 2: 3:    <script runat="server"> 4:       Sub tbMessage_Change(Sender As Object, E As EventArgs) 5:          lblMessage.Text = "Hello " + tbMessage.Text 6:       End Sub 7:    </script> 8: 9:    <html><body> 10:       <font size="5">Sam's Teach Yourself ASP.NET in 21 Days: 11:       Day 2</font><hr><p> 12:       <% Response.Write("Our First Page<p>") %> 13: 14:       <form runat="server"> 15:          Please enter your name: 16:          <asp:textbox  17:             OnTextChanged="tbMessage_Change" 18:             runat=server/> 19:          <asp:button  Text="Submit" 20:             runat=server/><p> 21:          <asp:label  font-size="20pt" 22:             runat=server/> 23:       </form> 24:    </body></html> 

It's easy to spot the different sections of ASP.NET code here in the code declaration block on lines 3 7, and in the code render block on line 12. You know what each section does as well. The first defines a method that the text box uses for its TextChanged event, and the second simply writes out "Our First Page<p>" to the browser.

Upon first request, the code declaration block is compiled into MSIL code, which is then translated into native machine code by the JIT compiler. However, the rest of the page, including the code render blocks, is evaluated at runtime when the page is loaded into the browser.

You can also see the three server controls in the form. These act similarly to regular HTML controls, but they provide additional functionality for your application. Days 5 and 6 will examine these and other server controls.

You've also examined the importance of the runat="server" attribute. Without it, ASP.NET pages wouldn't function correctly. This attribute is the key to maintaining the viewstate, and to providing a link between what happens in the browser and the actions the server should take.

After today's lesson, you'll be able to give intricate details on this page's mechanisms, both within the .NET Framework and from a user's perspective. You've come a long way in two days!


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    Sams Teach Yourself ASP. NET in 21 Days
    Sams Teach Yourself ASP.NET in 21 Days (2nd Edition)
    ISBN: 0672324458
    EAN: 2147483647
    Year: 2003
    Pages: 307
    Authors: Chris Payne

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