postback event error

[Wendi Taranto]

I have a dropDownList on a web page that is populated by client-side script.
I get an error on PostBack of the page. I've seen quite a few posts about
this, so I understand the issue, and why it's occurring. I added
EnableEventValidation="false" to my @Page directive, and now i can submit
the form with the client-side populated listbox. In my Protected Sub
btnSave_Click event, when I iterate the listbox that was populated
client-side, I cannot see any items in the list. Any ideas?

 

[Guest]

If I understand, ASP.Net looks up page's ViewState to re-populate(and set
controls) during post-back - hence, your dropDownList should contain the same
items list on the postback as it was populated during initial GET. If you
need to pass items from the client-side, I would suggest populating a hidden
field with on the client with all the items you need, and then reading them
on the server and manually re-populating your dropDown. You should also be
able to read the value in the dropDown with the code similar to the following:

Me.Request.Form(myDropDownList.UniqueID) ' in VB or
this.Request.Form[myDropDownList.UniqueID] ' in C#

This may be required as ASP.Net framework may not be able to match the value
from the Request object with the items loaded into your dropDownList from the
ViewState.

HTH