Dropdownlist Chain Visible

[newsgroups.jd]

I have a chain of drop down lists that populate based on the selection
from the previous drop down list. The 3rd and 4th drop down list, plus
a calendar - I would only like visible if certain choices are made in
the first and second drop down list.

I did using with similar to ....

Public Sub _OnSelectedIndexChanged1(ByVal Sender As Object, ByVal e As
EventArgs)
If DropDownList1.SelectedValue = "Choose a Report Category"
Then
DropDownList2.Visible = False
DropDownList3.Visible = False
masterCalendar.Visible = False
Else : DropDownList2.Visible = True
End If
End Sub
Public Sub _OnSelectedIndexChanged2(ByVal Sender As Object, ByVal e As
EventArgs)
If DropDownList2.SelectedValue = "Daily Reports" Then
masterCalendar.Visible = True
Else : masterCalendar.Visible = False
End If
End Sub

The questions I have is this.

1. Is this the best way to accomplish this?
2. How does changing the visibility properties affect multiple users,
using the site at the same time?

Thanks ahead of time... new to asp.net.

JD

 

[Cerebrus]

Hi JD,

I think that such UI modifications are best handled at the Client end
itself, and so you should use Client side scripting to enable / disable
or set visibility of such controls at the client browser.

I'm assuming that you've set the AutoPostBack property to True, and
with each SelectionChange, the event is raised, and the form posts back
to the server. In my opinion, there's always a performance penalty to
setting the AutoPostBack property of any control to True.

Of course, if the data in your Dropdown list is bound to a database,
then you cannot avoid posting back to the server. If it's only a
question of toggling visibility and filling some static items, then I
would suggest using Javascript (or VBScript) to do it.

To summarize, there are some validations that are best done at the
Client side, and some others that are most useful at the Server side.

Hope this helps,

Regards,

Cerebrus.

 

[newsgroups.jd]

Thanks...

You are correct I am using AutoPostBack and all the drop down lists are
populated by a database. Once this is done, I was going to create a
small front end for adding and removing items from the database ( to
edit the lists and URLs ). I had considered using static entries, but
so far between 4 dropdownlists I am up to over 100 entries.

JD