Alternatura - Introduction to ASP.NET (aspx)

Introduction to ASP.NET (aspx)

Preparing a development environment

Notes:

Like ASP Classic you can use Development GUI (VS.NET), but you can also edit your aspx files with any text editor since they are plain text.
Preferred OS: Windows 2000 or better, Windows XP or better

Installation:

If not already installed, install IIS from the OS Installation CD
Install all the latest critical updates, service packs and patches (run WindowsUpdate)
If not already installed, install the .NET framework. Run WindowsUpdate, go to the "Recommneded updates" section (following "Critical updates"). If .NET is not installed you will have it listed as an available. Select it to download and install. Or you can download ir here
Download and install the .NET Framework SDK. You need to install it in order to be sure that you will be able to run and test aspx applications. The .NET Framework alone does not guaratee this.
Create a folder under your IIS webroot directory (or a virtual IIS folder whereever) to store your aspx test files

aspx Structure

The main structure can be decomposed in:

Server Scripts section (<script runat="server"></script>) that includes

Events routines
User defined routines that may involve Server Controls

HTML body with Server Controls section embebed (<form runat="server"></form>)
The Server Control section is where the server is instrcuted to create the HTML output by programming "server components". These server components can be referred at the Server Scripts Section.
At the Server Control Section you may have
- HTML Server Controls - Traditional HTML tags with runat="server" attribute (<html_tag id="id" runat="server" ...other_tag_attributes... >...</html_tag>)
- Web Server Controls - New ASP .NET tags (<asp:control_type id="id" runat="server" ...other_tag_attributes... > ... </asp:control_type>)
- Validation Server Controls - For input validation (<asp:control_type id="id" runat="server" ...other_tag_attributes... > ... </asp:control_type>)

Example

<%--SERVER SCRIPTS SECTION BEGINS--%>
<script runat="server">
    <%-- SUBROUTINE INTERACTING WITH SERVER CONTROLS--%>
		<%--Sets the property TEXT of the BUTTON1 control defined in the server control section--%>
    Sub submit(Source As Object, e As EventArgs)
			button1.Text="You clicked me!"
    End Sub

<%--EVENT HANDLER FOR THE PAGE_LOAD EVENT--%>
    Sub Page_Load
    <%--Sets the HREF property of the LINK1 html server control defined in the server control section--%>
     link1.HRef="http://www.alternatura.com"

<%--Sets the TEXT of the LBL1 html server control defined in the server control section ONLY THE FIRST TIME THE PAGE IS LOADED--%>
     if Not Page.IsPostBack then
      lbl1.Text="The date and time is " & now()
     end if
    End Sub

</script>
<%--SERVER SCRIPTS SECTION ENDS--%>

<%-- CONVENTIONAL HTML BEGINS --%>
<html>
<body>

<%--HERE SOME CONVENTIONAL HTML YOU WANT TO ADD--%>

<%-- SOME CONVENTIONAL HTML... --%>
	HTML SERVER CONTROL EXAMPLE<HR>

<%--THIS IS A HTML SERVER CONTROL (an anchor)--%>
	<a id="link1" runat="server">Go to Alternatura</a>

<%-- SOME CONVENTIONAL HTML... --%>
	WEB SERVER CONTROLS EXAMPLES<HR>

<%--THIS IS A WEB SERVER CONTROL (a button control). THIS WILL PRODUCE THE HTML OUTPUT TO PRESENT A BUTTON IN THE CALLING BROWSER WITH THE ATTRIBUTES SET HERE AND THE REACTION TO EVENTS OR INTERACTION WITH SUBROUTINES DECLARED AT THE SERVER SCRIPTS SECTION--%> 
  <asp:Button id="button1" Text="Click me!" runat="server" OnClick="submit"/>
	<%--THIS IS A WEB SERVER CONTROL (a label control)--%> 
  <asp:label id="lbl1" runat="server" />

<%-- SOME CONVENTIONAL HTML... --%>
	ASP.NET WEB FORM EXAMPLE<HR>

<%--THIS IS A MINI-FORM WITH 2 WEB SERVER CONTROLS (text and button) WITH A VALIDATE SERVER CONTROL (a range validator) for the value in the text field when submitted--%>
  Enter a number from 1 to 100:
  <asp:TextBox id="tbox1" runat="server" />
  <br />
  <asp:Button Text="Submit" runat="server" />
  <br />
  <asp:RangeValidator
   ControlToValidate="tbox1"
   MinimumValue="1"
   MaximumValue="100"
   Type="Integer"
   EnableClientScript="false"
   Text="The value must be from 1 to 100!"
   runat="server" />

<%-- SOME CONVENTIONAL HTML... --%>
	<HR>

</form>
							
<%--HERE SOME CONVENTIONAL HTML YOU WANT TO ADD--%>

</body>
</html>
<%-- CONVENTIONAL HTML ENDS --%>

aspx Forms

Notes:

The server controls section is the only form in an aspx document.
You build your form there using HTML and server controls
ViewState: by default all the values of the form fields are maintained by .NET if the page is call back from its own code.
All the fields are presented in the browser with their values from the previous instance.
To disable this behavior for all the page declare <%@ Page EnableViewState="false" %> at the top of the aspx.
To disable this behavior for a specific server control add the attribute EnableViewState="false".