The VB code produces HTML that displays the following TABLE record data:
We''''ll get the titles from the database using the GetRows() method, which conveniently stores our record fields in a multidimensional array. In order to identify which title the user selects, a query string will be attached to the end of each hyperlinked title within the HTML code. This query string will use the titles'''' NoteID database field value, which is unique for each title.
Here''''s an example of how the title HTML <A> tags are structured within the TABLE TD tags sent back from our VB code to an ASP file, which we''''ll name NoteExample.asp. Notice that the user must have selected the "Buffering" title since <A> tags don''''t enclose it.
<TD WIDTH="74" NOWRAP VALIGN="top">
<FONT FACE="Verdana" SIZE="1" COLOR="GRAY">
<A HREF="NoteExample.asp?ID=1">Intro</A><BR>
<A HREF="NoteExample.asp?ID=2">Style Tables</A><BR>
<A HREF="NoteExample.asp?ID=3">GetRows()</A><BR>
Buffering<BR>
<A HREF="NoteExample.asp?ID=5">Transactions</A><BR>
</FONT>
</TD>
The URL for each title will send the user back to the current ASP file being displayed -- basically having the ASP file call itself when one of the titles is selected. The VB code will also assign a query string named "ID" to the end of each titles'''' URL within the <A> tag. The value of the ID query string will match each title''''s unique database record NoteID value. Every time our example NoteExample.asp file is called with an ID query string attached to the end of its URL, we''''ll send the ID query strings value to the VB code as a method parameter value so that the VB code will know which title was selected. So whether a URL with an ID query string is called from within the ASP file, or from another Internet link, the VB code will display the text of the title whose NoteID equals the ID query string value.
Below is the line of ASP code that will precede the call to the VB method and assign the "ID" query string variable value to a local ASP file variable. Basically, this line of code sets the local ASP variable named aspNoteID to the NoteID value of the title that the user selected. We''''ll then use the aspNoteID variable as a VB method parameter to let the VB method code know which notes'''' title text to display.
aspNoteID = Request.QueryString("ID")
If aspNoteID < 1 Then aspNoteID = 1
<TD WIDTH="124" VALIGN="top" BGCOLOR="#EFEFEF">
<FONT FACE="Verdana" SIZE="1" COLOR="NAVY">
This is an example application written for an article on server-side VB programming
</FONT>
</TD>
This, again, is a balancing of where to draw the line between presentation and business code. On one extreme, you could construct the entire ASP page''''s HTML code in the VB code, which would consist of all the code enclosed in, and including, the <HTML></HTML> tags. Other programmers would prefer to construct all the <A> tags, title values, title text, <FONT> tags, <TD> tags, etc., in the ASP file itself and just send back a recordset, or an array, from the VB code filled with the title names and selected title text. (See articles "How To Pass a RecordSet From a VB Component to an asp File" and "How To Pass a Variant Array Populated with a RecordSet From a VB Component to an asp File" at http://www.dougdean.com for more information on these alternatives). I have found sending back database field values within <TABLE> or <TD> tags is the best compromise that balances issues like maintenance, speed, source code security, etc.
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