Databases - ASP.Net Basic Forms
ASP.Net is Microsoft's new solution for connecting web pages
to a database.
This page is not intended as a tutorial
(for that, see the excellent references at the bottom of this page),
instead it
shows how ASP.Net code is translated into html
and is intended for a comparision to other pages on this site.
Element Comparisions
| aspx file
| Generated html
| References
Element Comparisions
This is a simple comparision of a few form elements
Of course, all ASP.Net elements have a
runat="server" parameter.
aspx file
This is a simple aspx (ASP.Net) file created with notepad.exe
<![CDATA[
<%@Page explicit="true" language="VB" debug="true" %>
<html>
<body>
Hello xx
<%
dim x, y
x=7
y=6
%>
<p>
<%= x %> + <%= y %> = <%= x+y %>
<form runat=server>
<asp:textbox runat=server tooltip="this is a test"/>
<asp:calendar runat=server tooltip="this is a test"/>
</form>
</body>
</html>
]]>
Generated html
This is the html the web browser sees (with
extra carriage returns added for readability,
some tabs removed and reformatted, and most of the calendar code removed
to save space).
<![CDATA[
<html>
<body>
Hello xx
<p>
7 + 6 = 13
<form name="_ctl0" method="post" action="FormControls.aspx" id="_ctl0">
<input type="hidden" name="__EVENTTARGET" value="" />
<input type="hidden" name="__EVENTARGUMENT" value="" />
<input type="hidden" name="__VIEWSTATE"
value="dDwtMzM4NzU1ODE7Oz4dyf3FM2eo8WmXStSu9j5rlzcckw==" />
<script language="javascript">
<!--
function __doPostBack(eventTarget, eventArgument) {
var theform;
if (window.navigator.appName.toLowerCase().indexOf("netscape") > -1) {
theform = document.forms["_ctl0"];
}
else {
theform = document._ctl0;
}
theform.__EVENTTARGET.value = eventTarget.split("$").join(":");
theform.__EVENTARGUMENT.value = eventArgument;
theform.submit();
}
// -->
</script>
<input name="_ctl1" type="text" title="this is a test" />
<table title="this is a test" cellspacing="0" cellpadding="2" border="0"
style="border-width:1px;border-style:solid;border-collapse:collapse;">
<tr><td colspan="7" style="background-color:Silver;">
<table cellspacing="0" border="0" style="width:100%;border-collapse:collapse;">
<tr>
<td style="width:15%;">
<a href="javascript:__doPostBack('_ctl2','V1643')" style="color:Black"><</a>
</td>
<td align="Center" style="width:70%;">August 2004</td>
<td align="Right" style="width:15%;">
<a href="javascript:__doPostBack('_ctl2','V1705')" style="color:Black">></a>
</td></tr>
</table></td></tr>
<tr><td align="Center">Sun</td>
<td align="Center">Mon</td>
(et cetera for the rest of the days)</tr>
<tr>
<td align="Center" style="width:14%;">
<a href="javascript:__doPostBack('_ctl2','1667')" style="color:Black">25</a></td>
<td align="Center" style="width:14%;">
<a href="javascript:__doPostBack('_ctl2','1668')" style="color:Black">26</a></td>
<td align="Center" style="width:14%;">
<a href="javascript:__doPostBack('_ctl2','1669')" style="color:Black">27</a></td>
(The table continues until all the days are shown)
</table>
</form>
</body>
</html>
]]>
Notice that all the links call __doPostBack ...
but with different parameters.
The first parameter specifies which ASP object was clicked,
the second is object specific.
Both are automatically assigned by IIS.
- _ctl0 - form
- _ctl1 - text (data entry) field
- _ctl2 - calendar
In addition to the values associated with form elements,
these 3 parameters are returned.
| __EVENTTARGET | set to the ASP object in __doPostBack
|
| __EVENTARGUMENT | set in __doPostBack
|
| __VIEWSTATE | set by IIS, used to recover state information
|
References
W2 Schools
provides a
very good tutorial
and
lots of examples
Author: Robert Clemenzi -
clemenzi@cpcug.org