Test if control state has changed after postback

[Guest]

I would like to add a test in my button event handler to see if one of the
controls has changed state. In this case, every time a dropdown list item has
been changed to 'Complete' status, I want save the current date to the
database as the completed date. I just need to know if the control has
changed from its pervious selected value or not.

Thanks

Earl

 

[Karl Seguin]

The only way would be to store the initial value somewhere (viewstate is a
good spot) then on button click retrieve the new selected value and compare
it to the value in the dropdown

sub button_click

dim oldValue as string = cstr(viewstate("previousValue"))
if oldValue <> ddl.SelectedValue then 'you might wanna check for null or
initialize the viewstate("previousValue") on the initial page_load
'value has changed, do whatever
viewState("previousValue") = ddl.SelectedValue 'store the new value as
the previous one
end if
end sub

Karl